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1
Wibowo, Mardi. "Pemodelan Sebaran Pencemaran Tumpahan Minyak di Perairan Cilacap." Jurnal Teknologi Lingkungan 19, no. 2 (July 31, 2018): 191. http://dx.doi.org/10.29122/jtl.v19i2.2812.
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ABSTRACTThe Cilacap coastal area plays an important role in recreation, transportation, energy, education or research, residential, and industry. It is also potential for development and potential for pollution especially for oil pollution. That is caused Cilacap has the refinary oil plant and the great port of oil, furthermore it has crowded traffic of ship (both big ship or fishing ships). All of which have a tremendous potential pollute the sea and the surrounding areas. Therefore, it’s needed study of oil slick spreading that caused oil spill to formulate early warning and protection action plan for Cilacap coastal area. This study use oil spill model from DHI (Danish Hydraulic Institute) and use software MIKE-21 modul Particle/Spill Analysis. At each scenario, direction and concentration of oil spill is highly varied, its depend on the hydrodynamic condition o sea water. In January the oil spill from the 70 area pier tends to spread upstream S, Donan and around P. Nusakambangan with slick thickness between 0.0001-2.1 mm and oil spill from SPM spread out south of the model domain. In September the oil spill in the 70 area dock spreads upstream of S Donan with slick thickness between 0.001-2.7 mm and oil spills in SPM spread evenly throughout Cilacap waters with slick thickness between 0.001 to 1 mm. The result of this study is very important to plan early warning system and reduce environmental impact of oil spill. Based on comparation tide model data to tide data from field measuring, its known that both of data has no significance differences.Keywords: oil spill spreading, computational modeling, hydrodynamicsABSTRAKKawasan pesisir Cilacap memiliki potensi pengembangan wilayah yang sangat besar. Namun demikian, kawasan ini juga mempunyai ancaman terhadap pencemaran tumpahan minyak, terutama disebabkan oleh aktivitas kapal, kebocoran pipa, single point mooring (SPM), dan kapal nelayan yang dapat merusak ekosistem perairan Cilacap dan sekitarnya. Karena itu, kajian persebaran minyak diperlukan untuk menyusun tindakan peringatan dini dan perlindungan kawasan pesisir Cilacap. Dalam kajian ini dilakukan pemodelan penyebaran minyak dengan menggunakan model tumpahan minyak dari DHI (Danish Hydraulic Institute) dan perangkat lunak MIKE-21 modul Particle/Spill Analysis. Berbagai parameter inputan data diperoleh dari data sekunder dan hasil survei lapangan pada 8-14 Januari dan 10 16 September 2012. Terdapat empat model skenario penyebaran disusun dan hasil akhir divalidasi dengan hasil pengukuran. Sebagai hasil, arah persebaran dan konsentrasi tumpahan minyak untuk tiap skenario sangat bervariasi dari waktu ke waktu tergantung pada kondisi hidrodinamika perairan yang ada. Pada bulan Januari tumpahan minyak dari dermaga area 70 cenderung menyebar ke hulu S. Donan dan di sekitar P. Nusakambangan dengan ketebalan slick antara 0,0001-2,1 mm dan tumpahan minyak dari SPM tersebar ke selatan keluar ari domain model. Pada bulan September tumpahan minyak di dermaga area 70 tersebar ka arah hulu S Donan dengan ketebalan slick antara 0,001-2,7 mm dan tumpahan minyak di SPM tersebar merata ke seluruh wialayah perairan Cilacap dengan ketebalan slick antara 0,001- 1 mm. Hasil kajian ini sangat penting sebagai dasar perencanaan upaya peringatan dini tumpahan minyak dan meminimalisasi dampak tumpahan minyak. Validasi data pasang surut hasil pemodelan dan pengukuran lapangan dari Intergovernmental Oceanographic Commission (IOC) menunjukkan tidak adanya perbedaan yang nyata.Kata kunci: persebaran tumpahan minyak, pemodelan komputasi, hidrodinamika
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Christoffersen, Bradley O., Manuel Gloor, Sophie Fauset, Nikolaos M. Fyllas, David R. Galbraith, Timothy R. Baker, Bart Kruijt, et al. "Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)." Geoscientific Model Development 9, no. 11 (November 24, 2016): 4227–55. http://dx.doi.org/10.5194/gmd-9-4227-2016.
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Abstract. Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ε, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs), and the leaf : sapwood area ratio Al : As). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity (Amax), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model predictions. The plant hydraulics model made substantial improvements to simulations of total ecosystem transpiration. Remaining uncertainties and limitations of the trait paradigm for plant hydraulics modeling are highlighted.
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Yan, Bing Bing, Wen Bo Ren, Bao Lin Yin, and Yang Li. "Hydraulic System Simulation of 3-UPS Parallel Mechanism Based on ADAMS/Hydraulics." Key Engineering Materials 579-580 (September 2013): 430–33. http://dx.doi.org/10.4028/www.scientific.net/kem.579-580.430.
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In order to guaranty the work stability of the move-in-mud robot and movement relationship of wriggle turning joint, to use the 3-UPS parallel mechanism as the steering joint. Make full use of the characteristics flexibility, heavy force loading and small workspace of the parallel mechanism. Supporting link of the parallel mechanism driven by hydraulic cylinders, so a completely hydraulic system is an important factor to ensure the stationary work of parallel mechanism, provide the required power to go forward and ensure the forward speed of the move-in-mud robot. Establish the virtual prototype model of mechanical-hydraulic coupling system by using of Pro/E and ADAMS/Hydraulics software, do the dynamic simulation analysis of hydraulic control system based on Hydraulics module, the simulation process can be made more visual and vivid by three-dimensional visualization. Obtain the platform speed and hydraulic cylinder pressure curve after simulation, compare simulation results with theoretical calculations, and verify that the design is reasonable. The results show that it lays the foundation for the further optimization and research of the move-in-mud robot.
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Javaux, Mathieu, and Andrea Carminati. "Soil hydraulics affect the degree of isohydricity." Plant Physiology 186, no. 3 (March 31, 2021): 1378–81. http://dx.doi.org/10.1093/plphys/kiab154.
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A soil–plant hydraulic model shows that the degree of isohydricity is constrained by below-ground hydraulic limitations and that the shape of plant water potential (WP) curve depends on soil hydraulics.
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Sembiring, Tagor Malem, Surian Pinem, and Peng Hong Liem. "VALIDATION OF FULL CORE GEOMETRY MODEL OF THE NODAL3 CODE IN THE PWR TRANSIENT BENCHMARK PROBLEMS." JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA 17, no. 3 (October 4, 2015): 141. http://dx.doi.org/10.17146/tdm.2015.17.3.2322.
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ABSTRACT VALIDATION OF FULL CORE GEOMETRY MODEL OF THE NODAL3 CODE IN THE PWR TRANSIENT BENCHMARK PROBLEMS. The coupled neutronic and thermal-hydraulic (T/H) code, NODAL3 code, has been validated in some PWR static benchmark and the NEACRP PWR transient benchmark cases. However, the NODAL3 code have not yet validated in the transient benchmark cases of a control rod assembly (CR) ejection at peripheral core using a full core geometry model, the C1 and C2 cases. By this research work, the accuracy of the NODAL3 code for one CR ejection or the unsymmetrical group of CRs ejection case can be validated. The calculations by the NODAL3 code have been carried out by the adiabatic method (AM) and the improved quasistatic method (IQS). All calculated transient parameters by the NODAL3 code were compared with the reference results by the PANTHER code. The maximum relative difference of 16% occurs in the calculated time of power maximum parameter by using the IQS method, while the relative difference of the AM method is 4% for C2 case. All calculation results by the NODAL3 code shows there is no systematic difference, it means the neutronic and T/H modules are adopted in the code are considered correct. Therefore, all calculation results by using the NODAL3 code are very good agreement with the reference results. Keywords: nodal method, coupled neutronic and thermal-hydraulic code, PWR, transient case, control rod ejection. ABSTRAK VALIDASI MODEL GEOMETRI TERAS PENUH PAKET PROGRAM NODAL3 DALAM PROBLEM BENCHMARK GAYUT WAKTU PWR. Paket program kopel neutronik dan termohidraulika (T/H), NODAL3, telah divalidasi dengan beberapa kasus benchmark statis PWR dan kasus benchmark gayut waktu PWR NEACRP. Akan tetapi, paket program NODAL3 belum divalidasi dalam kasus benchmark gayut waktu akibat penarikan sebuah perangkat batang kendali (CR) di tepi teras menggunakan model geometri teras penuh, yaitu kasus C1 dan C2. Dengan penelitian ini, akurasi paket program NODAL3 untuk kasus penarikan sebuah CR atau sekelompok CR yang tidak-simetris dapat divalidasi. Perhitungan paket program NODAL3 dilakukan dengan metode adiabatic (AM) dan improved quasistatic (IQS). Seluruh parameter gayut waktu hasil perhitungan paket program NODAL3 dibandingkan dengan hasil acuan dengan paket program PANTHER. Perbedaan relatif maksimum sebesar 16% terjadi dalam perhitungan parameter waktu daya maksimum dengan metode IQS pada kasus C2, sedangkan perbedaan relatif dengan metode AM adalah 4%. Seluruh hasil perhitungan dengan paket program NODAL3 menunjukkan tidak adanya perbedaan yang sistematis, berarti modul neutronik dan T/H yang diadopsi di NODAL3 sudah benar. Oleh karena itu, seluruh perhitungan dengan paket program NODAL3 sangat sesuai dengan hasil acuan. Kata kunci: metode nodal, paket program kopel neutonik dan termo-hidrolika, kasus gayut-waktu, tertariknya batang kendali.
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Guo, Xiao Le, Zhi Ming Wang, and Zhi Hui Long. "Research Progresses of Hydraulics for Extended Reach Drilling in China, Part III: Hydraulics Design Method and Risk Analysis System." Advanced Materials Research 524-527 (May 2012): 1561–64. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1561.
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The extended reach drilling (ERD) is being adopted widely in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for ERD. In the paper of “Research Progresses and Perspectives of Hydraulics for Extended Reach Drilling in China, Part I” and “ Part II”, the author demenstrated part of these progresses including cuttings transport model, precise model of pressure loss calculation, hole cleaning monitoring method and hydraulic extended limit calculation model and analysis. In this paper, the rest were presented which inlcuding hydraulics design method and risk analysis system for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk analysis before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.
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Parekh, Siddharth, Ali Pilehvari, and Robert Serth. "Prediction of Fluid Behavior Using Generalized Hydraulic Calculation Method in Hydraulic Fractures." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 81, no. 1 (March 5, 2021): 120–30. http://dx.doi.org/10.37934/arfmts.81.1.120130.
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Hydraulic fracturing has been used as one of the stimulation techniques to economically increase oil and gas production by creating small cracks in subsurface geologic formations to allow oil or gas to move toward a producing well. Hydraulics plays a vital role in many oil field operations including drilling, completion, fracturing and production. In the case of fracturing, however, the role of hydraulics becomes important since optimized hydraulics can minimize the cost and conversely, any miscalculations may cause problems such as the fluid loss or may potentially even lead to loss of the well. The current methods of the hydraulic calculation for non-Newtonian fluids necessitate determination of the robust model. This paper presented a new method for calculating pressure losses in the hydraulic fractures. The objective of this study was to develop the generalized model for hydraulic calculation for non-Newtonian fluid and run the case studies for the model validation. In the present work, detailed algorithm for the hydraulic calculation has been developed and then programmed in C++. The only input to the program is the raw rheological data, shear stress versus shear rate and the geometrical characteristics of the slit. Model validation with the new method has established a very small percentage difference between the values predicted by the model and experimental data. The results demonstrate that the new method is accurately predicting the pressure drop in both laminar and turbulent flow regimes. It is shown that the fluid behavior is more accurately represented using the new method than that with the standard fluid models available in the petroleum industry. Further validation and development to be carried out using experimental data for variety of fluid types.
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Taghavi, Mehdi, and Hesam Ghodousi. "Simulation of Flow Suspended Load in Weirs by Using Flow3D Model." Civil Engineering Journal 1, no. 1 (November 1, 2015): 37–49. http://dx.doi.org/10.28991/cej-2015-00000004.
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Sharp-crested weir and side-channel weirs can be considered among the control and flow-measuring structures which are greatly applicable in channels, dam spillways and other hydraulic structures. Discharge coefficient in these two types of weirs is affected by the structural geometry and the hydraulics of the flow. Suspended load is one of the main factors which may affect the hydraulics of the flow and consequently modify the flow discharge coefficient. Using different geometrical and hydraulic conditions, the discharge coefficient relation in sharp-crested and side channel weirs for the case of suspended load can be extracted. Flow3D numerical model is capable of precisely simulation the flow containing suspended and bed load in the main channel. The discharge coefficient equation is deduced and presented based on the Froude number, by numerical iterations. The numerical results reveal that the discharge coefficient in the two cases of clear water and the flow containing suspended load are totally different. At the same hydraulic load, the discharge coefficient in the case of existing suspended load is greater than the case of clear water; In addition, the discharge coefficient is reduced by increasing the Froude number in all cases with different load concentrations.
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Guo, Xiao Le, Zhi Ming Wang, and Zhi Hui Long. "Hydraulics Analysis System for Extended Reach Drilling in China and its Application." Applied Mechanics and Materials 241-244 (December 2012): 1349–53. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1349.
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The extended reach drilling (ERD) is being adopted widely as an effective and economical way of developing oilfields in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for extended reach drilling, which included cuttings transport models and rules, precise model of circulating system pressure loss calculation, hole cleaning calculating models and monitoring method, hydraulic extended limit calculation model and analysis, hydraulics design and optimization method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk assess before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.
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Zhong, Xiang Qiang, and Li Dong Liang. "Mechanical-Hydraulic Coupling Simulation for Hydraulic Excavator Working Mechanism." Advanced Materials Research 538-541 (June 2012): 494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.494.
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Hydraulic excavator is a typical and complicated engineering machine by combination of mechanical, control and hydraulic system. It is very important for coupling analysis by use of multiple simulation tools. Hydraulic excavator mechanical model was constructed based on Pro/E 4.0. Virtual prototype of hydraulic excavator was finished by use of ADAMS interface function and carried on a lot of kinematics and dynamics simulation analysis. Hydraulic cylinder circuit was derivated based on ADAMS/Hydraulics. Working principle of bucket arm hydraulic cylinder was analyzed. Mechanical and hydraulic simulation of bucket rod hydraulic cylinder was finished. Bucket rod hydraulic cylinder velocity was obtained. Simulation results show coupling simulations have certain theory value and practical significance. They can provide evidence for trial and optimization of physical prototype.
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Guo, Xiao Le, Zhi Ming Wang, and Zhi Hui Long. "Research Progresses of Hydraulics for Extended Reach Drilling in China Part II: Hole Cleaning Monitoring and Hydraulic Extended Limit." Advanced Materials Research 524-527 (May 2012): 1553–56. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1553.
Full textAbstract:
The extended reach drilling (ERD) is being adopted widely in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for ERD. In the paper of “Research Progresses and Perspectives of Hydraulics for Extended Reach Drilling in China, Part I”, the author demenstrated part of these progresses including cuttings transport model and precise model of pressure loss calculation. In this paper, the part of rest were presented which inlcuding hydraulic extended limit calculation model and analysis and hole cleaning monitoring method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk analysis before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.
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Guo, Xiao Le, Zhi Ming Wang, and Zhi Hui Long. "Research Progresses of Hydraulics for Extended Reach Drilling in China, Part I: Cuttings Transport and Precise Calculation of Pressure Loss." Advanced Materials Research 524-527 (May 2012): 1557–60. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1557.
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The extended reach drilling (ERD) is being adopted widely as an effective and economical way of developing oilfields in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for extended reach drilling, which included cuttings transport models and rules, precise model of circulating system pressure loss calculation, hole cleaning calculating models and monitoring method, hydraulic extended limit calculation model and analysis, hydraulics design and optimization method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk assess before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD. Due to space limitations, this article could only demonstrate part of these progresses, as the subtitle showed.
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Ose, Yasuo, Hisashi Tanigawa, and Yoshinori Kawamura. "ICONE23-2059 NUMERICAL ANALYSIS OF THERMAL HYDRAULIC BEHAVIOR BASED ON TWO-FLUID MODEL DURING INGRESS OF COOLANT EVENT IN BLANKET MODULE." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2015.23 (2015): _ICONE23–2—_ICONE23–2. http://dx.doi.org/10.1299/jsmeicone.2015.23._icone23-2_22.
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Anwar, Shadab. "A generalized model for pumping well hydraulics in confined aquifers." Journal of Hydroinformatics 20, no. 5 (May 23, 2018): 1085–99. http://dx.doi.org/10.2166/hydro.2018.158.
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Abstract A generalized model for well hydraulics in confined aquifers is presented. The lattice Boltzmann method (LBM)-based altered-velocity model is used to simulate well hydraulics in homogeneous and heterogeneous confined aquifers for different pumping conditions. LBM is applied to simulate well hydraulics in two different configurations of heterogeneous aquifer, where (1) a circular disk of material or (2) an infinite linear strip of material is embedded in a matrix of differing hydraulic properties. The effect of hydrogeologic boundaries on drawdown curve in confined aquifers is simulated using LBM. The LBM is further applied to simulate drawdown during harmonic pumping well test. The LBM data in lattice units are scaled to physical units using non-dimensional discharge rate and diffusion length. The results from LBM were found to be sensitive to the relaxation parameter and the RMS error for drawdown was found to be less than 1% for later time. This work will verify the potential of LBM to simulate well hydraulics in homogeneous and heterogeneous confined aquifers for constant, step, and harmonic pumping.
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Suwardiyono, Suwardiyono. "Pengaruh Waktu Tunggal Biomassa (SRT) Terhadap Kualitas Limbah Cair Indistri Tekstil Dengan Proses Lumpur Aktif-Membran." REAKTOR 5, no. 2 (June 13, 2017): 41. http://dx.doi.org/10.14710/reaktor.5.2.41-47.
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Penelitian proses gabungan lumpur aktif- membrane ini merupakan penggabungan proses lumpur aktif konvensional, dalam rangka upaya peningkatan kinerja proses. Dalam system ini, membrane berfungsi sebagai pengganti bak sedimentasi. Proses pengolahan diharapkan bias beroprasi pada konsentrasi biomassa dan waktu tinggal iomassa yang tinggi serta menghasilkan sitem yang kompak.Pada penelitian ini digunakan limbah cair industry tekstil dengan COD 795-1148 mg/l dan mikroorganisme dari sistem proses lumpur aktif konvensional. Proses membrane yang digunakan adalah mikrofiltrasi crossflow dengan modul hollow fiber terbuat dari polipropilen,ukuran pori 0,2 mikron dan luas permukaan membran 0,0226 m2. Proses pengolahan berlangsung pada waktu tinggal cairan (hydraulic retention time, HRT) tetap 9 jam dan waktu tinggal lumpur ( solid retention time, SRT) divariasikan, yaitu 24, 32, 40, dan 48 hari. Dengan variasi SRT tersebut dapat diketahui pengaruh SRT terhadap kinerja proses dan kualitas keluaran.Kondisi proses membrane pada penelitian ini TMP 0,4 bar dan laju alir silang 0,88 m/s serta tekanan back backflushing 1,6 bar, selang waktu 1,5 menit dan lama back fluching 1 detik. Dengan kondisi ini, diperoleh fluks stabil 5,04 l/(jam.m2) pada berbagai SRT. Pada keadaan tunak, didapatkan MLSS semakin besar, dengan peningkatan SRT. Konsentrasi COD keluaran semakin kecil seiring dengan kenaikan SRT, yaitu pada SRT 24,32, 40 dan 48 hari berturut-turut 198, 126,79 dan 38 mg/ l. Dan efisiensi penyisihan COD yang diperoleh semakin besar seiring dengan kenaikan SRT, yaitu pada SRT 24, 32, 40, dan 48 hari berturut-turut 80,85%; 87,59%; 92,08% dan 96,26%.Kata kunci : kualitas limbah, limbah cair, proses lumpur aktif-membran, waktu tinggal biomassa (solid retention time, SRT)
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Křepela, J., and Vladislav Singule. "Simulation of the Dynamic Behaviors of the C Axis Drive by the Turning Center." Solid State Phenomena 147-149 (January 2009): 356–61. http://dx.doi.org/10.4028/www.scientific.net/ssp.147-149.356.
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The paper describes the mathematical model for C axis of the multifunction turning center with worm gear. Talks about the mathematical model with multi-body mass dynamic system. The drive works in the positional feedback and his mathematical model is specified for detection of the dynamical behaviors of the C axis. The turning center is designed for a heavy roughing forged piece from high carbon steels by the power of main motor 71kW. The C axis must be designed as accurate angle position axis and with big dynamic stability of regulation by step or pulse loading. The C axis drive is constructed with help of a hydraulic connected up the worm gearing on a spindle. The driven side of the worm gear is created two dual worms with own servomotors. Worm wheel is solved as one part with two gears. Servomotors are controlled with the mode speed/torque coupling (MASTER-SLAVE), which guarantees the constant torque prestressing between the servomotors. The difference of a torques guarantees leaning of both worm teeth on opposite tooth faces of both gears of the worm wheel. In the dynamic model are involved the friction on the worm gears, torsion stiffness located with help of the FEM and moment of inertia for all parts. 3D models of the C axis is designed in the program ProEngineer. From complete 3D model of the C axis are transfered individual parts to the FEM in surroundings Ansys as volume parts. In this paper is main output influence of the diference between the 3D and 2D for calculation of the stiffness in the contact of the worm gear on the whole dynamic system of the C axis. The value of the torsion stiffness by more situation of the load on the worm gear is used subsequently to the multi-body mass system of the C axis drive and to the eigen frequencies analyses. Results of this paper will be sensitivity check of the changing torsion stiffness on the worm gear by the loading changing on the resulted position accuracy on the C axis. Next review is, if the control modul MASTER-SLAVE is partially this problem of the difference between values of stiffness from 2D or 3D model or also stiffness non-linearity eliminated.
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Liu, Yanlan, Nataniel M. Holtzman, and Alexandra G. Konings. "Global ecosystem-scale plant hydraulic traits retrieved using model–data fusion." Hydrology and Earth System Sciences 25, no. 5 (May 10, 2021): 2399–417. http://dx.doi.org/10.5194/hess-25-2399-2021.
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Abstract. Droughts are expected to become more frequent and severe under climate change, increasing the need for accurate predictions of plant drought response. This response varies substantially, depending on plant properties that regulate water transport and storage within plants, i.e., plant hydraulic traits. It is, therefore, crucial to map plant hydraulic traits at a large scale to better assess drought impacts. Improved understanding of global variations in plant hydraulic traits is also needed for parameterizing the latest generation of land surface models, many of which explicitly simulate plant hydraulic processes for the first time. Here, we use a model–data fusion approach to evaluate the spatial pattern of plant hydraulic traits across the globe. This approach integrates a plant hydraulic model with data sets derived from microwave remote sensing that inform ecosystem-scale plant water regulation. In particular, we use both surface soil moisture and vegetation optical depth (VOD) derived from the X-band Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer for Earth Observing System (EOS; collectively AMSR-E). VOD is proportional to vegetation water content and, therefore, closely related to leaf water potential. In addition, evapotranspiration (ET) from the Atmosphere–Land Exchange Inverse (ALEXI) model is also used as a constraint to derive plant hydraulic traits. The derived traits are compared to independent data sources based on ground measurements. Using the K-means clustering method, we build six hydraulic functional types (HFTs) with distinct trait combinations – mathematically tractable alternatives to the common approach of assigning plant hydraulic values based on plant functional types. Using traits averaged by HFTs rather than by plant functional types (PFTs) improves VOD and ET estimation accuracies in the majority of areas across the globe. The use of HFTs and/or plant hydraulic traits derived from model–data fusion in this study will contribute to improved parameterization of plant hydraulics in large-scale models and the prediction of ecosystem drought response.
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Vanderborght, Jan, Valentin Couvreur, Felicien Meunier, Andrea Schnepf, Harry Vereecken, Martin Bouda, and Mathieu Javaux. "From hydraulic root architecture models to macroscopic representations of root hydraulics in soil water flow and land surface models." Hydrology and Earth System Sciences 25, no. 9 (September 6, 2021): 4835–60. http://dx.doi.org/10.5194/hess-25-4835-2021.
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Abstract. Root water uptake is an important process in the terrestrial water cycle. How this process depends on soil water content, root distributions, and root properties is a soil–root hydraulic problem. We compare different approaches to implement root hydraulics in macroscopic soil water flow and land surface models. By upscaling a three-dimensional hydraulic root architecture model, we derived an exact macroscopic root hydraulic model. The macroscopic model uses the following three characteristics: the root system conductance, Krs, the standard uptake fraction, SUF, which represents the uptake from a soil profile with a uniform hydraulic head, and a compensatory matrix that describes the redistribution of water uptake in a non-uniform hydraulic head profile. The two characteristics, Krs and SUF, are sufficient to describe the total uptake as a function of the collar and soil water potential, and water uptake redistribution does not depend on the total uptake or collar water potential. We compared the exact model with two hydraulic root models that make a priori simplifications of the hydraulic root architecture, i.e., the parallel and big root model. The parallel root model uses only two characteristics, Krs and SUF, which can be calculated directly following a bottom-up approach from the 3D hydraulic root architecture. The big root model uses more parameters than the parallel root model, but these parameters cannot be obtained straightforwardly with a bottom-up approach. The big root model was parameterized using a top-down approach, i.e., directly from root segment hydraulic properties, assuming a priori a single big root architecture. This simplification of the hydraulic root architecture led to less accurate descriptions of root water uptake than by the parallel root model. To compute root water uptake in macroscopic soil water flow and land surface models, we recommend the use of the parallel root model with Krs and SUF computed in a bottom-up approach from a known 3D root hydraulic architecture.
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Hotchkiss, Rollin H., Patrick J. Flanagan, and Kevin Donahoo. "Hydraulic Jumps in Broken-Back Culverts." Transportation Research Record: Journal of the Transportation Research Board 1851, no. 1 (January 2003): 35–44. http://dx.doi.org/10.3141/1851-04.
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A broken-back culvert has one or more changes in grade within the prismatic barrel profile. One section of a broken-back culvert is usually steep, with the steep slope contributing to high outlet velocities unless a hydraulic jump forms upstream from the culvert outlet. Predictive equations have been published for a wide range of experimental conditions but still do not describe the hydraulics of a jump as it traverses the steeply sloped section and the most downstream section of a broken-back culvert. A computer program, the Broken-Back Culvert Analysis Program (BCAP), analyzes the hydraulics of circular or box-shaped broken-back culverts and provides a comprehensive design tool for engineers. It predicts whether a hydraulic jump will occur and, if so, where it begins and ends. Analyses are performed for 10 discharges. Outputs include rating curves for headwater and outlet depths and outlet velocity and tabulations of hydraulic parameters for each discharge. The water surface profiles throughout the culvert, except through the hydraulic jump, are computed and are plotted on the screen. Experiments were performed with model culverts to assess the accuracy of the predictive equations in BCAP for headwater depth, the location of a hydraulic jump, and the hydraulic jump length. The predictions for the headwater depth at the culvert inlet matched the experimental observations well, but predictions for hydraulic jump location and length were less satisfactory. BCAP has been used for hundreds of design projects in Nebraska and has been downloaded almost 300 times from at least 22 different states. It is recommended that BCAP be improved as better experimental data become available.
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Perrin, O., S. Christophe, F. Jacquinod, and O. Payrastre. "VISUAL ANALYSIS OF INCONSISTENCIES IN HYDRAULIC SIMULATION DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B4-2020 (August 25, 2020): 795–801. http://dx.doi.org/10.5194/isprs-archives-xliii-b4-2020-795-2020.
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Abstract. We present our contribution to the geovisualization and visual analysis of hydraulic simulation data, based on an interdisciplinary research work undertaken by researchers in geographic information sciences and in hydraulics. The positive feedback loop between researchers favored the proposal of visualization tools enabling visual reasoning on hydraulic simulated data so as to infer knowledge on the simulation model. We interactively explore and design 2D multi-scale styles to render hydraulic simulated data, in order to support the identification over large simulation domains of possible local inconsistencies related to input simulation data, simulation parameters or simulation workflow. Models have been implemented into QGIS and are reusable for other input data and territories.
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Mursinna, A., Erica McCormick, Katie Van Horn, Lisa Sartin, and Ashley Matheny. "Plant Hydraulic Trait Covariation: A Global Meta-Analysis to Reduce Degrees of Freedom in Trait-Based Hydrologic Models." Forests 9, no. 8 (July 25, 2018): 446. http://dx.doi.org/10.3390/f9080446.
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Current vegetation modeling strategies use broad categorizations of plants to estimate transpiration and biomass functions. A significant source of model error stems from vegetation categorizations that are mostly taxonomical with no basis in plant hydraulic strategy and response to changing environmental conditions. Here, we compile hydraulic traits from 355 species around the world to determine trait covariations in order to represent hydraulic strategies. Simple and stepwise regression analyses demonstrate the interconnectedness of multiple vegetative hydraulic traits, specifically, traits defining hydraulic conductivity and vulnerability to embolism with wood density and isohydricity. Drought sensitivity is strongly (Adjusted R2 = 0.52, p < 0.02) predicted by a stepwise linear model combining rooting depth, wood density, and isohydricity. Drought tolerance increased with increasing wood density and anisohydric response, but with decreasing rooting depth. The unexpected response to rooting depth may be due to other tradeoffs within the hydraulic system. Rooting depth was able to be predicted from sapwood specific conductivity and the water potential at 50% loss of conductivity. Interestingly, the influences of biome or growth form do not increase the accuracy of the drought tolerance model and were able to be omitted. Multiple regression analysis revealed 3D trait spaces and tradeoff axes along which species’ hydraulic strategies can be analyzed. These numerical trait spaces can reduce the necessary input to and parameterization of plant hydraulics modules, while increasing the physical representativeness of such simulations.
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Tacail, François G., Barry Evans, and Alan Babb. "Case study of a labyrinth weir spillway." Canadian Journal of Civil Engineering 17, no. 1 (February 1, 1990): 1–7. http://dx.doi.org/10.1139/l90-001.
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A labyrinth weir is an effective and economical means of providing increased spillway capacity under some restricted operating conditions. This type of weir is particularly suited to reservoir sites where a low head to high discharge relation is required, the topography restricts the spillway width, and a self-operating structure is highly desirable for emergency operation. Over the past few decades, labyrinth weir spillways have been constructed throughout the world. Definitive guidelines and theoretical procedures pertaining to hydraulic design of this type of weir are not completely established. The designer is confronted with the use of empirical methods for determining spillway configurations which require careful design and verification by use of a hydraulic model. This paper describes the design and hydraulic model study conducted for a labyrinth weir arrangement proposed for the South Heart Dam in northern Alberta. The model study permitted the designers to adopt a more efficient two-cycle weir for the same spillway width as opposed to an initially proposed three-cycle labyrinth weir. Key words: labyrinth weir, spillways, weirs, floods, hydraulic structures, hydraulics.
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Mohammed, Jamal AK, Walaa M. Hashim, and Bahaa S. Beram. "Performance Improvement of a Conventional Hydraulic Elevator by Using Electro-Hydraulic Servo Mechanism." Engineering and Technology Journal 38, no. 5A (May 25, 2020): 748–60. http://dx.doi.org/10.30684/etj.v38i5a.367.
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An electro-hydraulic elevator is a new type of enhanced elevators that are used in low-rise buildings that do not exceed more than three floors. In this paper, an electro-hydraulic servo system for controlling the speed of a hydraulic elevator prototype by using a proportional valve and PID controller was investigated theoretically and experimentally. A three floors elevator prototype model with 76cm height was built including hydraulics components and electrical components. The elevator system is fully automated using the Arduino UNO board based Data Acquisition (DAQ) system. LabVIEW software is used to control the hydraulic elevator system through L298 DC drive via the DAQ board. The best PID gains was obtained experimentally. The elevator system prototype could be emplimented for educational purposes; such as learning the undergraduate students in the Electromechanical Engineering Department in the University of Technology how to structuring the electro-hydraulic elevator as well as the appropriate control strategy.
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Žitný, R., A. Landfeld, J. Skočilas, J. Stancl, V. Flegl, M. Zachariášová, M. Jírů, and M. Houška. "Hydraulic characteristic of collagen." Czech Journal of Food Sciences 33, No. 5 (June 3, 2016): 479–85. http://dx.doi.org/10.17221/62/2015-cjfs.
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Hydraulic characteristic of collagen. Czech J. Food Sci., 33: 479–485. The hysteresis of a hydraulic characteristic while pumping an aqueous solution of collagen through a pipe at gradually increasing and decreasing flow rates (hysteresis means that the pressure drop curve during increased flow rate is above the pressure drop during decreasing flow rate) was observed. The problem was initiated by industry and by demand for an on-line recording of rheological properties of collagenous material used for extrusion of collagen casings. The Herschel-Bulkley rheological model was capable to describe rheograms in a wide range of deformation rates; however it was not able to describe and explain the hysteresis. As a possible reason thixotropic properties were identified and the hydraulic characteristic was calculated using a thixotropic generalisation of the Herschel-Bulkley model. The developed 1D numerical model can be applied for on-line modelling of transient flows of incompressible thixotropic food materials (startup flow) and at a limited range of flow rates it is also capable to describe the hysteresis of hydraulic characteristics.
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Bayon-Barrachina, Arnau, and Petra Amparo Lopez-Jimenez. "Numerical analysis of hydraulic jumps using OpenFOAM." Journal of Hydroinformatics 17, no. 4 (March 13, 2015): 662–78. http://dx.doi.org/10.2166/hydro.2015.041.
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The present paper deals with a hydraulic jump study, characterization and numerical modeling. Hydraulic jumps constitute a common phenomenon in the hydraulics of open channels that increases the shear stress on streambeds, so promoting their erosion. A three-dimensional computational fluid dynamics model is proposed to analyze hydraulic jumps in horizontal smooth rectangular prismatic open-air channels (i.e., the so-called classical hydraulic jump). Turbulence is modeled using three widely used Reynolds-averaged Navier–Stokes (RANS) models, namely: Standard k − ɛ, RNG k − ɛ, and SST k − ω. The coexistence of two fluids and the definition of an interface between them are treated using a volume method in Cartesian grids of several element sizes. An innovative way to deal with the outlet boundary condition that allows the size of the simulated domain to be reduced is presented. A case study is conducted for validation purposes (FR1 ∼ 6.10, Re1 ∼ 3.5·105): several variables of interest are computed (sequent depths, efficiency, roller length, free surface profile, etc.) and compared to previous studies, achieving accuracies above 98% in all cases. In the light of the results, the model can be applied to real-life cases of design of hydraulic structures.
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Donahue, John P., and Andrew F. Howard. "Hydraulic design of culverts on forest roads." Canadian Journal of Forest Research 17, no. 12 (December 1, 1987): 1545–51. http://dx.doi.org/10.1139/x87-237.
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Design of drainage structures is an important part of planning forest roads, which usually includes culverts. Determining the appropriate pipe size for a given site involves estimation of expected flows and evaluation of the hydraulic performance of pipes of different sizes. In this paper a review of the hydraulic relationships applicable to the evaluation of pipe hydraulics is presented. A computer model is introduced that incorporates these relationships. The model is used to compare two algorithms for computing headwater depths, given inlet control (supercritical flow). The relative efficiency of four inlet types was also investigated. Results indicate that potential cost savings exist by altering inlet geometry and that computer-assisted design can facilitate accommodation of conflicting design goals.
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Matus, Sean A., Francina Dominguez, Daniel R. Gambill, and Heidi R. Howard. "Embracing Uncertainty: Using Probabilistic Weather Forecasts to Make Ensemble Hydraulic Predictions at Remote Low-Water Crossings." Journal of Hydrometeorology 21, no. 5 (May 2020): 953–69. http://dx.doi.org/10.1175/jhm-d-19-0238.1.
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AbstractLow-water crossings are structures designed to be overtopped during high river flows. These structures are usually constructed in remote locations, making timely emergency response difficult in case of flooding. In this work, five historical flooding events were hindcasted at a remote low-water crossing in central Texas. An ensemble of model-simulated precipitation forcing cascades uncertainty through hydrologic and hydraulic models. Each precipitation ensemble member corresponds to an independent model run, resulting in an ensemble 24-h streamflow forecast initialized at 0000 UTC. In addition to the hydrologic conditions, the forecast is expanded to predict river hydraulics, through flow velocity and depth. Analysis of the five hindcast events indicates that cascading probabilistic precipitation through hydrologic and hydraulic models adds robustness to river forecasts compared to deterministic methods. The approach provides a means to communicate the uncertainty of predictions through the ensemble spread. Analysis of deterministic hazard thresholds suggest that a hydraulic stability threshold, calculated as the multiplication of flow velocity and depth, is a useful alternative approach to NWS high-water categories for communicating hydrologic/hydraulic risk, as well as associated model uncertainty in the simplest manner possible.
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Ying, Qiang. "Design and Application of Internal Flat-Pool Measuring Weir." Advanced Materials Research 971-973 (June 2014): 1141–43. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.1141.
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Base on the mechanism of surge tank and measuring weir, an internal flat-pool measuring weir has been developed which can be applied in flow rate measuring area such as the hydraulics labs, the hydraulic engineering model labs and the river regulation project model labs. This new device functions well even with site limitation and unstable current. This passage introduces the mechanism of measuring weir with a few examples.
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Zou, Kai Ming, Xi'an Yang, and Jun Li. "Layout and Hydraulics Model Experiments of Filling and Emptying System of Shiplock Structure with Chamber Wall’s Long Culvert and Short Side Orifice Outlet." Advanced Materials Research 639-640 (January 2013): 745–51. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.745.
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The safety and efficency of operation of shiplock ralate closely to the filling and emptying system,so its related hydraulics will become the research focus of the current navigation hydraulics.According to requirement of the general layout codes and relevant design provisions of filling and emptying system,the hydraulic characteristics of the filling and emptying system with chamber wall’s long culvert and short side orifice outlet，is carried out by generalized numerical model and overall physical mode.The results showed that the hydraulic property of the structure can meet the requirements of the standard,and the research is also very important to ensure the safe operation,the reseach method can make reference for similar project.
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Richard, G. L., and S. L. Gavrilyuk. "The classical hydraulic jump in a model of shear shallow-water flows." Journal of Fluid Mechanics 725 (May 16, 2013): 492–521. http://dx.doi.org/10.1017/jfm.2013.174.
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AbstractA conservative hyperbolic two-parameter model of shear shallow-water flows is used to study the classical turbulent hydraulic jump. The parameters of the model, which are the wall enstrophy and the roller dissipation coefficient, are determined from measurements of the roller length and the deviation from the Bélanger equation of the sequent depth ratio (experimental data by Hager & Bremen, J. Hydraul. Res., vol. 27, 1989, pp. 565–585; and Hager, Bremen & Kawagoshi, J. Hydraul. Res., vol. 28, 1990, pp. 591–608). Stationary solutions to the model describe with a good accuracy the free-surface profile of the hydraulic jump. The model is also capable of predicting the oscillations of the jump toe. We show that if the upstream Froude number is larger than ${\sim }1. 5$, the jump toe oscillates with a particular frequency, while for the Froude number smaller than 1.5 the solution becomes stationary. In particular, we show that for a given flow discharge, the oscillation frequency is a decreasing function of the Froude number.
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Carleton, Tyler J., and Steven R. Fassnacht. "Linking Hydrologic and Hydraulic Data with Models to Assess Flow and Channel Alteration at Hog Park, Wyoming USA." Hydrology 7, no. 2 (May 23, 2020): 29. http://dx.doi.org/10.3390/hydrology7020029.
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Transbasin diversions and dams allow for water uses when and where there is high demand and low supply, but can come with an expense to the environment. This paper presents a linkage of hydrologic and hydraulic modeling and datasets to assess the hydrologic and hydraulic stability within a transbasin watershed as an approach for meeting water use targets and safeguarding environmental sustainability. The approach used a Prediction in Ungauged Basin (PUB) regionalization technique that completed the parameterization of a study watershed hydrologic model by transferring calibrated parameters from a reference watershed hydrologic model. This resulted in a long-term, simulated natural flow record that was compared to the measured modified flow record for the same time period to assess flow alteration. In the sensitive reach, hydraulic modeling results tracked channel response from before hydrologic modification to baseline using repeated survey years during the hydrologic modification. The combined assessment of hydrology and hydraulics highlighted the relation between flow regime and channel form.
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Nguyen, Thuy Huu, Matthias Langensiepen, Jan Vanderborght, Hubert Hüging, Cho Miltin Mboh, and Frank Ewert. "Comparison of root water uptake models in simulating CO<sub>2</sub> and H<sub>2</sub>O fluxes and growth of wheat." Hydrology and Earth System Sciences 24, no. 10 (October 23, 2020): 4943–69. http://dx.doi.org/10.5194/hess-24-4943-2020.
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Abstract. Stomatal regulation and whole plant hydraulic signaling affect water fluxes and stress in plants. Land surface models and crop models use a coupled photosynthesis–stomatal conductance modeling approach. Those models estimate the effect of soil water stress on stomatal conductance directly from soil water content or soil hydraulic potential without explicit representation of hydraulic signals between the soil and stomata. In order to explicitly represent stomatal regulation by soil water status as a function of the hydraulic signal and its relation to the whole plant hydraulic conductance, we coupled the crop model LINTULCC2 and the root growth model SLIMROOT with Couvreur's root water uptake model (RWU) and the HILLFLOW soil water balance model. Since plant hydraulic conductance depends on the plant development, this model coupling represents a two-way coupling between growth and plant hydraulics. To evaluate the advantage of considering plant hydraulic conductance and hydraulic signaling, we compared the performance of this newly coupled model with another commonly used approach that relates root water uptake and plant stress directly to the root zone water hydraulic potential (HILLFLOW with Feddes' RWU model). Simulations were compared with gas flux measurements and crop growth data from a wheat crop grown under three water supply regimes (sheltered, rainfed, and irrigated) and two soil types (stony and silty) in western Germany in 2016. The two models showed a relatively similar performance in the simulation of dry matter, leaf area index (LAI), root growth, RWU, gross assimilation rate, and soil water content. The Feddes model predicts more stress and less growth in the silty soil than in the stony soil, which is opposite to the observed growth. The Couvreur model better represents the difference in growth between the two soils and the different treatments. The newly coupled model (HILLFLOW–Couvreur's RWU–SLIMROOT–LINTULCC2) was also able to simulate the dynamics and magnitude of whole plant hydraulic conductance over the growing season. This demonstrates the importance of two-way feedbacks between growth and root water uptake for predicting the crop response to different soil water conditions in different soils. Our results suggest that a better representation of the effects of soil characteristics on root growth is needed for reliable estimations of root hydraulic conductance and gas fluxes, particularly in heterogeneous fields. The newly coupled soil–plant model marks a promising approach but requires further testing for other scenarios regarding crops, soil, and climate.
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Matz, Radosław, Ryszard Błażejewski, Tadeusz Nawrot, and Maciej Pawlak. "Hydraulic Capacity and Efficiency of a Low-Speed Nonpressurized Coil Pump." Water 11, no. 8 (August 10, 2019): 1659. http://dx.doi.org/10.3390/w11081659.
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The paper presents the results of an investigation on hydraulics of a low-speed coil pump for transport of liquids. One of the pump’s advantages is its wide range of potential inclination angles for its rotating shaft, from the horizontal to an almost vertical position. A simplified hydraulic model was developed based on kinematic and geometrical considerations to determine the pump capacity. The model was verified under laboratory conditions using a low-speed coil pump composed of transparent PVC tube (15 mm outer diameter) wound around a cylindrical drum (104 mm external diameter; 550 mm long). Laboratory tests were performed for three angles of inclination of the axis of rotation (20°, 40°, and 60°) and four rotational speeds (10, 20, 30, and 40 rpm). The results of the tests showed satisfactory agreement with the hydraulic model predictions. Energetic efficiency was estimated on the base of electric power measurements and difference of water levels in the two arms of rotating transparent torus, partly filled with water. The hydraulic efficiency of the coil pump is increasing with decreasing rotational speed.
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Zakharov, Viacheslav, and Tatiana Minav. "Analysis of Field Oriented Control of Permanent Magnet Synchronous Motor for a Valveless Pump-Controlled Actuator." Proceedings 64, no. 1 (November 20, 2020): 19. http://dx.doi.org/10.3390/iecat2020-08491.
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Earlier research demonstrated that a pump-controlled hydraulic system combines the best properties of traditional hydraulics and electric intelligence. Thus, the new system has been proposed as a replacement for conventional valve-controlled systems, to improve the energy efficiency in non-road mobile machinery in particular. One of the pump-controlled systems can be realized via direct control of hydraulic pump/motor by varying speed of prime mover. Electric motor (EM) as a prime mover attract with higher efficiency (more than 90%) and a wide range of speed regulation. These advantages allow to improve the system efficiency and decrease the energy consumption in electric and hybrid non-road mobile machinery. Further EM's efficiency improvement can be achieved by using vector control systems, which provide rotor magnetic flux control proportionally to the shaft's speed. Considering all vector control’s benefits (high accuracy of speed control, smooth~start and smooth rotation of the motor in the entire frequency range, quick response to load changes, increased control range and accuracy of regulation), the electro-hydraulic systems and influence of electric part on hydraulic one is not investigated widely. Therefore, in this paper Field Oriented Control (FOC) is analyzed as One of the most perspective vector control systems for electro-hydraulic actuator application with a Permanent Magnet Synchronous Machine (PMSM) as a prime mover. In~this study, Direct-driven hydraulics (DDH) was considered as a study case. A detailed model of the PMSM control system with DDH was built in MATLAB/Simulink. The behavior of the DDH system was investigated by transient processes analysis of EM, pump, and cylinder in the normal and failure modes. The system demonstrates a difference between reference and simulated speed about 0.33% and 11.75% of average torque fluctuations. The behavior of the system in failure mode demonstrated multiple excesses of rated parameters.
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Dai, Li, Yao Wu, Jian Wang, Yun Gong Li, and Yu Liu. "Modeling and Control of Flexible Hydraulic Robotic Arm." Advanced Engineering Forum 2-3 (December 2011): 334–39. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.334.
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Flexible hydraulic robotic arm is a complicated system which coupled by mechanics and hydraulics. It is widely applied in all kinds of large engineering equipments, such as concrete pump truck, bridge monitor truck, arm frame of crane, etc. The arm system of the hydraulic robotic arm is a multi-body system with redundant freedom, strong nonlinear, coupled with rigid and flexible characters. So it is of great theoretic value and real engineering significance to study the arm system of the robotic arm. In this theme, the movement of flexible hydraulic robotic arm and hydraulic cylinders are seperately analyzed with flexible multi-body dynamics, and the mechanical hydraulic dynamic model of the driving system and the arm system is built with Lagrange Equation and Virtual Work Theory. And the dynamic differential equation is built with the driving force of the hydraulic cylinder as the main force. With the track programming and the optimization method, the dynamic converse problem of the arm end track is researched, so as to get the optimized rotation angle when the arm end reaches the expected point. By using the PD control theory, without decoupling and rank-decreasing, only with feed back from the hydraulic system to realize the close loop control of the arm end position, pose and movement, the relationship between the hydraulic system and the end position & pose is studied, so that the flexible distortion is reduced and the libration is restrained. What’s more, the simulation model of the mechanical arms is built by the dynamic simulation software. The simulation result prove that the movement equation built by this way can clearly describe each dynamic character of the mechanical arms.
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Tonina, Daniele, and John M. Buffington. "A three-dimensional model for analyzing the effects of salmon redds on hyporheic exchange and egg pocket habitat." Canadian Journal of Fisheries and Aquatic Sciences 66, no. 12 (December 2009): 2157–73. http://dx.doi.org/10.1139/f09-146.
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A three-dimensional fluid dynamics model is developed to capture the spatial complexity of the effects of salmon redds on channel hydraulics, hyporheic exchange, and egg pocket habitat. We use the model to partition the relative influences of redd topography versus altered hydraulic conductivity (winnowing of fines during spawning) on egg pocket conditions for a simulated pool–riffle channel with a redd placed at the pool tail. Predictions show that altered hydraulic conductivity is the primary factor for enhancing hyporheic velocities and dissolved oxygen content within the egg pocket. Furthermore, the simulations indicate that redds induce hyporheic circulation that is nested within that caused by pool–riffle topography and that spawning-related changes in hyporheic velocities and dissolved oxygen content could create conditions suitable for incubation in locations that otherwise would be unfavorable (reinforcing the notion that salmonids actively modify their environment in ways that may be beneficial to their progeny).
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Gems, B., S. Achleitner, M. Plörer, F. Schöberl, M. Huttenlau, and M. Aufleger. "Bed-load transport modelling by coupling an empirical routing scheme and a hydrological-1-D-hydrodynamic model – case study application for a large alpine valley." Advances in Geosciences 32 (December 11, 2012): 23–30. http://dx.doi.org/10.5194/adgeo-32-23-2012.
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Abstract. Sediment transport in mountain rivers and torrents is a substantial process within the assessment of flood related hazard potential and vulnerability in alpine catchments. Focusing on fluvial transport processes, river bed erosion and deposition considerably affects the extent of inundation. The present work deals with scenario-specific bed-load transport modelling in a large alpine valley in the Austrian Alps. A routing scheme founding on empirical equations for the calculation of transport capacities, incipient motion conditions and drag forces is set up and applied to the case study area for two historic flood events. The required hydraulic data result from a distributed hydrological-1-D-hydraulic model. Hydraulics and bed-load transport are simulated sequentially providing a technically well-founded and feasible methodology for the estimation of bed-load transport rates during flood events.
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Mohammadpour Zalaki, Sajjad, Hosein Fathian, Ebrahim Zalaghi, and Farhad Kalantar Hormozi. "Investigation of hydraulic parameters and cavitation in Kheir Abad flood release structure." Canadian Journal of Civil Engineering 42, no. 4 (April 2015): 213–21. http://dx.doi.org/10.1139/cjce-2014-0409.
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The simulation of flow behaviors before the construction of spillways using physical model and simulating packages is a crucial task. This paper investigates the flow behaviors in Kheir Abad flood release structure on Ab Shirin River, Iran by using Flow3D software and the results were compared with those of the physical model. First, by setting up a virtual model of spillway, the software performance was verified and calibrated. Then, by entering different flow discharge values, the two-dimensional flow hydraulics through the spillway was simulated by the software and flow depths, velocities and pressure were obtained for different flow discharges along the spillway. The cavitation was calculated based on the hydraulic parameters. The results show that Flow3D software is capable of simulating two-dimensional hydraulic flow over spillways. The results also indicate that the Kheir Abad flood release structure performs well during flood events considering cavitation.
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Baird, Drew, Benjamin Abban, S. Scurlock, Steven Abt, and Christopher Thornton. "Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations." Water 13, no. 4 (February 10, 2021): 458. http://dx.doi.org/10.3390/w13040458.
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While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.
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Lohrasbi, Alireza, Moharram Dolatshahi Pirooz, and Alireza Lavaei. "Hydraulic Model of Dam Break Using Navier Stokes Equation with Arbitrary Lagrangian-Eulerian Approach." International Journal of Engineering and Technology 8, no. 4 (April 2016): 249–53. http://dx.doi.org/10.7763/ijet.2016.v6.893.
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Lohrasbi, Alireza, Moharram Dolatshahi Pirooz, and Alireza Lavaei. "Hydraulic Model of Dam Break Using Navier Stokes Equation with Arbitrary Lagrangian-Eulerian Approach." International Journal of Engineering and Technology 8, no. 4 (April 2016): 249–53. http://dx.doi.org/10.7763/ijet.2016.v8.893.
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Izumi, Tomoki, Junichiro Takeuchi, Toshihiko Kawachi, Koichi Unami, and Shigeya Maeda. "An Inverse Method to Estimate Soil Hydraulic Properties in Saturated-unsaturated Groundwater Flow Model." Journal of Rainwater Catchment Systems 13, no. 2 (2008): 23–28. http://dx.doi.org/10.7132/jrcsa.kj00004871197.
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Sweeney, D. G., N. J. Cromar, J. B. Nixon, C. T. Ta, and H. J. Fallowfield. "The spatial significance of water quality indicators in waste stabilization ponds - limitations of residence time distribution analysis in predicting treatment efficiency." Water Science and Technology 48, no. 2 (July 1, 2003): 211–18. http://dx.doi.org/10.2166/wst.2003.0123.
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Over the past fifty years, considerable research in waste stabilization pond operation has led to the development of a number of models used to describe the hydraulic regime and predict treatment efficiency. Models range in complexity from plug or completely mixed simplifications to computational fluid dynamics (CFD) models which are able to predict flow hydraulics at a local level. Information about the exit age of pond effluent can be used to estimate pollutant decay. However, a mechanistic approach to understanding pond operation highlights the importance of knowing both the time and spatial history of pond effluent. A CFD model of a large pond system was constructed to demonstrate various hydraulic scenarios under different boundary conditions. Two scenarios were compared to visually demonstrate the effects of differing hydraulic conditions. Typical mechanistic models were applied to each condition to quantify biological differences. This simple example indicates that integrating biological and localised flow models will lead to a more holistic understanding of pond operation and treatment efficiency.
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Marthews, T. R., C. A. Quesada, D. R. Galbraith, Y. Malhi, C. E. Mullins, M. G. Hodnett, and I. Dharssi. "High-resolution hydraulic parameter maps for surface soils in tropical South America." Geoscientific Model Development 7, no. 3 (May 6, 2014): 711–23. http://dx.doi.org/10.5194/gmd-7-711-2014.
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Abstract. Modern land surface model simulations capture soil profile water movement through the use of soil hydraulics sub-models, but good hydraulic parameterisations are often lacking, especially in the tropics. We present much-improved gridded data sets of hydraulic parameters for surface soil for the critical area of tropical South America, describing soil profile water movement across the region to 30 cm depth. Optimal hydraulic parameter values are given for the Brooks and Corey, Campbell, van Genuchten–Mualem and van Genuchten–Burdine soil hydraulic models, which are widely used hydraulic sub-models in land surface models. This has been possible through interpolating soil measurements from several sources through the SOTERLAC soil and terrain data base and using the most recent pedotransfer functions (PTFs) derived for South American soils. All soil parameter data layers are provided at 15 arcsec resolution and available for download, this being 20x higher resolution than the best comparable parameter maps available to date. Specific examples are given of the use of PTFs and the importance highlighted of using PTFs that have been locally parameterised and that are not just based on soil texture. We discuss current developments in soil hydraulic modelling and how high-resolution parameter maps such as these can improve the simulation of vegetation development and productivity in land surface models.
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Jaeger, Y., D. Lénès, M. Le Bihan, A. Ponthieux, and A. Génin. "Disinfection optimization by a better control of ozonation process." Water Supply 9, no. 6 (December 1, 2009): 699–706. http://dx.doi.org/10.2166/ws.2009.674.
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Currently, ozonation installations in French drinking water treatment plants are operated in order to ensure an ozone residual of 0.4 mg/L at the outlet of the contactor with a contact time of 4 minutes which guarantee, with regards to the USEPA tables, a 4 log virus inactivation. Veolia Water has launched a thorough study concerning hydraulics in ozonation contactors which goals are (1) to reach the disinfection level desired through a better supervision of operating conditions, (2) to guarantee good hydraulic performances to reduce ozone production and ozonation-by products (bromates). The validation of these objectives is related to a relevant control of every ozonation tank with a Ct criteria considering from now their geometry, which condition their hydraulic efficiency. In comparison with CSTR method, the Ct10 method has been judged as the most relevant. Veolia is working with such a tank control, which definitely requires the determination of its hydraulic efficiency. Considering that numerical modelling of the ozonation contactors will be very long and expensive, the project team is working on the determination of an analytical model expression for hydraulic efficiency. The objective is to create an innovative tool which enables plant operators themselves to easily determine the hydraulic efficiency of inter or post ozonation tank.
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Liu, Y. S., D. F. Wu, L. Long, and S. P. Cao. "Research on the port valve of a water hydraulic axial pump." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 3 (April 24, 2009): 155–66. http://dx.doi.org/10.1243/09544089jpme237.
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Water hydraulics using water as the working media is paid more attention because of its many advantages compared with oil ones. Water hydraulic pump is the key component in the applications of water hydraulics. Compared with the water hydraulic pump with port plate, the one with port valve has stronger anti-pollution ability and is more suitable for the open system where the working media cannot be filtered finely. For this kind of pump, the characteristics of port valve have direct and significant influences on the flow and pressure characteristics of the pump. In this article, the flow and pressure characteristics of different valves were compared experimentally and a disc valve was selected as the port valve. Then the mathematical model of a single-piston pump with port valve was built and the influences of different factors including spring rigidity, working pressure, etc. on the port valve were analysed. At last, a single-piston pump was developed to test the characteristics of the port valve. Based on these researches, some principles that should be abided in the design of the port valve were suggested.
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Li, Hongmei, Xingjie Lu, Zhongwang Wei, Siguang Zhu, Nan Wei, Shupeng Zhang, Hua Yuan, et al. "New Representation of Plant Hydraulics Improves the Estimates of Transpiration in Land Surface Model." Forests 12, no. 6 (June 1, 2021): 722. http://dx.doi.org/10.3390/f12060722.
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Transpiration represents more than 30% of the global land–atmosphere water exchange but is highly uncertain. Plant hydraulics was ignored in traditional land surface modeling, but recently plant hydraulics has been found to play an essential role in transpiration simulation. A new physical-based representation of plant hydraulic schemes (PHS) was recently developed and implemented in the Common Land Model (CoLM). However, it is unclear to what extent PHS can reduce these uncertainties. Here, we evaluated the PHS against measurements obtained at 81 FLUXNET sites. The transpiration of each site was estimated using an empirical evapotranspiration partitioning approach. The metric scores defined by the International Land Model Benchmarking Project (ILAMB) were used to evaluate the model performance and compare it with that of the CoLM default scheme (soil moisture stress (SMS)). The bias score of transpiration in PHS was higher than SMS for most sites, and more significant improvements were found in semi-arid and arid sites where transpiration was limited by soil moisture. The hydraulic redistribution in PHS optimized the soil water supply and thus improved the transpiration estimates. In humid sites, no significant improvement in seasonal or interannual variability of transpiration was simulated by PHS, which can be explained by the insensitivity of transpiration demand coupled to the photosynthesis response to precipitation. In arid and semi-arid sites, seasonal or interannual variability of transpiration was better captured by PHS than SMS, which was interpreted by the improved drought sensitivity for transpiration. Arid land is widespread and is expected to expand due to climate change, thus there is an urgent need to couple PHS in land surface models.
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Cui, Yunsong, Qiuhua Liang, Gang Wang, Jiaheng Zhao, Jinchun Hu, Yuehua Wang, and Xilin Xia. "Simulation of Hydraulic Structures in 2D High-Resolution Urban Flood Modeling." Water 11, no. 10 (October 15, 2019): 2139. http://dx.doi.org/10.3390/w11102139.
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Urban flooding as a result of inadequate drainage capacity, failure of flood defenses, etc. is usually featured with highly transient hydrodynamics. Reliable and efficient prediction and forecasting of these urban flash floods is still a great technical challenge. Meanwhile, in urban environments, the flooding hydrodynamics and process may be influenced by flow regulation and flood protection hydraulic infrastructure systems, such as sluice gates, which should be effectively taken into account in an urban flood model. However, direct simulation of hydraulic structures is not a current practice in 2D urban flood modeling. This work aims to develop a robust numerical approach to directly simulate the effects of gate structures in a 2D high-resolution urban flood model. A new modeling component is developed and fully coupled to a finite volume Godunov-type shock-capturing shallow water model, to directly simulate the highly transient flood waves through hydraulic structures. Different coupling approaches, i.e., flux term coupling and source term coupling, are implemented and compared. A numerical experiment conducted for an analytical dam-break test indicates that the flux term coupling approach may lead to more accurate results, with the calculated RMSE against water level 28%–38% less than that produced by the source term coupling approach. The flux term coupling approach is therefore adopted to improve the current urban flood model, and it is further tested by reproducing the laboratory experiments of flood routing in a flume with partially open sluice gates, conducted in the hydraulic laboratory at the Zhejiang Institute of Hydraulics and Estuary, China. The numerical results are compared favorably with experimental measurements, with a maximum RMSE of 0.0851 for all the individual tests. The satisfactory results demonstrate that the flood model implemented with the flux coupling approach is able to accurately simulate the flow through hydraulic structures, with enhanced predictive capability for urban flood modeling.
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Loi, Nguyen Kim, Nguyen Duy Liem, Le Hoang Tu, Nguyen Thi Hong, Cao Duy Truong, Vo Ngoc Quynh Tram, Tran Thong Nhat, Tran Ngoc Anh, and Jaehak Jeong. "Automated procedure of real-time flood forecasting in Vu Gia – Thu Bon river basin, Vietnam by integrating SWAT and HEC-RAS models." Journal of Water and Climate Change 10, no. 3 (August 24, 2018): 535–45. http://dx.doi.org/10.2166/wcc.2018.015.
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Abstract The precise and reliable simulation of hydrologic and hydraulic processes is important for efficient flood forecasting and warning. The study proposes a real-time flood forecasting system which integrates a coupled hydrological-hydraulic modeling system, weather station network, and stream gauges in a web-based visualization environment. An automated procedure was developed for linking dynamically terrestrial rainfall-runoff processes and river hydraulics by coupling the SWAT hydrological model and the HEC-RAS hydraulic model. The flood forecasting system was trialed in the Vu Gia – Thu Bon river basin, Quang Nam province, Vietnam. The results showed good statistical correlation between predicted and measured stream flow for a 10-year calibration period (R² = 0.95, NSI = 0.95, PBIAS = −1.54) and during the following 10-year validation period as well (R² = 0.93, NSI = 0.93, PBIAS = 6.18). A close-up analysis of individual storm events indicated that the magnitude and timing of peak floods were accurately predicted in 2015 (R² = 0.88, NSI = 0.69, PBIAS = 4.50) and 2016 (R² = 0.80, NSI = 0.93, PBIAS = 6.18). In addition, the automated procedure was demonstrated to be reliable with dependable computational efficiency of less than 5 minutes' processing time.
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Ahmad Abdul Ghani, Nadiatul Adilah, Junaidah Ariffin, and Duratul Ain Tholibon. "Robustness Analysis of Model Parameters for Sediment Transport Equation Development." ASM Science Journal 12 (July 22, 2019): 1–17. http://dx.doi.org/10.32802/asmscj.2019.268.
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Robustness analysis of model parameters for sediment transport equation development is carried out using 256 hydraulics and sediment data from twelve Malaysian rivers. The model parameters used in the analyses include parameters in equations by Ackers-White, Brownlie, Engelund-Hansen, Graf, Molinas-Wu, Karim-Kennedy, Yang, Ariffin and Sinnakaudan. Seven parameters in five parameter classes were initially tested. Robustness of the model parameters was measured on the statistical relations through Evolutionary Polynomial Regression (EPR) technique and further examined using the discrepancy ratio of the predicted versus the measured values. Results from analyses suggest (ratio of shear velocity to flow velocity) and (ratio of hydraulic radius to mean sediment diameter) to be the most significant and influential parameters for the development of sediment transport equation.