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1
Li, Dongfei, Ning Dai, Hongtao Wang i Fujun Zhang. "Mathematical Modeling Study of Pressure Loss in the Flow Channels of Additive Manufacturing Aviation Hydraulic Valves". Energies 16, nr 4 (10.02.2023): 1788. http://dx.doi.org/10.3390/en16041788.
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The application of additive manufacturing in the field of aviation hydraulics greatly improves the design freedom of hydraulic valve internal flow channels. Pressure loss in hydraulic valve internal flow channels is a primary factor that designers need to consider, and the rapid prediction of pressure loss is very helpful for flow channel design. At present, most studies only focus on how much the pressure loss in an additive manufacturing (AM) hydraulic channel is reduced compared with an original hydraulic channel, and a mathematical model of pressure loss in an AM curved channel is still lacking. In this paper, the pressure loss in a curved flow channel was firstly studied, and the main parameters affecting the pressure loss were determined using the dimensionless analysis method. Using computational fluid dynamics simulation, the relationships between the flow channel diameter, the flow channel length, the flow channel curvature radius, the fluid velocity and pressure loss were studied. According to the multiple regression analysis method, the mathematical model of pressure loss in aviation hydraulic channels was developed, and the model was solved based on the orthogonal experimental results. The pressure loss in the flow channel samples fabricated using selective laser melting was tested, and the results showed that the average error between the test results and the mathematical model calculation results was 7.72%. This model can be used to quickly predict the pressure loss in curved flow channels in the aviation hydraulic field.
2
Hager, Willi H. "Trapezoidal side-channel spillways". Canadian Journal of Civil Engineering 12, nr 4 (1.12.1985): 774–81. http://dx.doi.org/10.1139/l85-091.
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Steady flows in trapezoidal, prismatic side-channel spillways are analysed using a hydraulic approach. Distinction between channels of small and moderate bottom slopes is made. All results are presented in typical nondimensional quantities, by which an immediate application is made possible. Key words: open channel flow, spillway, gradually varied flow, discharge supply, hydraulics.
3
Stefanyshyn, Dmytro V., Yaroslaw V. Khodnevich i Vasyl M. Korbutiak. "Еstimating the Chézy roughness coefficient as a characteristic of hydraulic resistance to flow in river channels: a general overview, existing challenges, and ways of their overcoming". Environmental safety and natural resources 39, nr 3 (23.09.2021): 16–43. http://dx.doi.org/10.32347/2411-4049.2021.3.16-43.
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This paper deals with results of a systemized overview of the Chézy roughness coefficient calculation problem as one most frequently used empirical characteristics of hydraulic resistance. The overview is given in the context of the formation of reliable empirical data needed to support hydro-engineering calculations and mathematical modelling of open flows in river channels. The problem topicality is because of a large number of practical tasks which need such a pre-research. In many cases, the accuracy of determining empirical hydraulic resistance characteristics can largely affect the accuracy of solving tasks relating to designing hydraulic structures and water management regardless of chosen mathematical models and methods.Rivers are characterized by a significant variety of flow conditions; hydraulic resistance to flows in rivers can thus vary widely determining their flow capacity. Considering the variety of river hydro-morphology and hydrology, the Chézy roughness coefficient often appears to be the most complete characteristic of hydraulic resistance to open flows in river channels comparing with other integral empirical characteristics of hydraulic resistance.At present, there are a large number of empirical and semi-empirical formulas to calculate the Chézy roughness coefficient. The main aim of this study was to analyze and systematize them in the context of providing proper support to the open channel hydraulics tasks. To achieve the aim of the study, a literature review regarding the problem of determining the integral hydraulic resistance characteristics to open flow in river channels was performed, as well as formulas used to calculate the Chézy roughness coefficient in practice were explored and systemized. In total, 43 formulas to calculate the Chézy roughness coefficient, as well as 13 formulas that can be used to estimate the Manning roughness coefficient were analyzed and systematized. Based on all these formulas, about 250 empirical equations can be compiled to calculate the Chézy coefficient depending on hydro-morphological peculiarities of rivers and river channels, hydraulic conditions, formulas application limits, and so on.
4
Zuikov, Andrey, i Tatiana Suehtina. "Hydraulics of smoothly streamlined Venturi channels of critical depth". E3S Web of Conferences 91 (2019): 07021. http://dx.doi.org/10.1051/e3sconf/20199107021.
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The article relates to the field of hydraulics and engineering hydrology and is devoted to a study of fluid flow in a non-flooded Venturi channel. The purpose of the work is improvement of methods for calculating profiles and hydraulic characteristics of a Venturi flumes used for measurement of water flow rates in open channels and rivers. Research methods are analytical with experimental verification. A functional relationship is obtained between the Froude number in an arbitrary section of the Venturi channel and its width normalized by the width of the critical section. It is established that within a rectilinear gorge portion of a Venturi channel, the flow is unstable, which is related to the proximity of its parameters to the critical ones. The method of optimization of a profile of a Venturi channel with a dividing cross-section in a gorge that does not contain empirical coefficients is considered. It is shown that the proposed method allows determining all main geometric parameters and hydraulic characteristics of the Venturi flume, including its flow rate coefficient, distribution of depths and flow velocities along the length of a flume with a relative error of ±1%.
5
Verdiyev, A. "The Method of Predicting the Confidence Interval by the Culvert Capacity of Channels at the Design Stage". Bulletin of Science and Practice, nr 12 (15.12.2022): 372–81. http://dx.doi.org/10.33619/2414-2948/85/44.
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The purpose of the research is to develop a methodology for predicting confidence intervals of functional parameters of main channels at the design stage, taking into account the probability of absolute changes occurring in their hydraulic parameters during construction and operation. In this regard, taking into account that during the construction and operation of main channels, the frequency of absolute changes in the values of the living cross-section area, wetted perimeter, hydraulic radius and bottom slope obeys the normal distribution law, and the channel roughness coefficient is an increasing and arbitrarily variable random variable, the possibility of predicting the probable confidence interval for the channel’s culvert over the period of operation is investigated. For this purpose, the Monte Carlo method and the Excel program were used, and a method for predicting the confidence interval of the design value of the channel flow rate was proposed. The corresponding analyses were carried out according to the design values of hydraulic parameters on the studied sections of the main channels operated in the Republic of Azerbaijan. Assuming that the design value of each hydraulic parameter is an average value, and the mean square deviation is within the probability, the generation of normally distributed random variables is compiled (provided that the channel roughness coefficient is an increasing and arbitrarily variable value in the appropriate limit), and according to the flow formula for a steady uniform movement, the maximum flow rate of the channel is calculated. The confidence interval of the average value of the predicted maximum flow rate is determined and compared with the design value of the maximum flow rate on the studied section of the trunk channel. Based on the proposed method, the effect of influencing the average value of the maximum flow rate was analyzed in the case of the roughness coefficient of the channel remains unchanged, and probabilistic scattering of other hydraulic parameters occurs around the design values, as well as, in general, the corresponding hydraulic parameters are scattered around the design values.
6
Voinov, Nikolaj Aleksandrovich, Anastasiya Viktorovna Bogatkova, Nina Vladimirovna Deryagina, Denis Andreevich Zemtsov i Nataliya Yul`evna Kozhukhova. "RESISTANCE OF TANGENTIAL SWIRLERS WITH ANNULAR CHANNELS". chemistry of plant raw material, nr 1 (10.03.2022): 335–42. http://dx.doi.org/10.14258/jcprm.2022019670.
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A review of vortex apparatuses and processes in which a rotating gas-liquid flow is used as an intensification of heat and mass transfer is presented.
It is shown that tangential swirlers, which are easy to manufacture and compact, have found the greatest application in industrial practice for creating gas (steam) rotation.
It is experimentally established that tangential swirlers with annular walls of channels intended for gas passage have the lowest hydraulic resistance.
The data on the hydraulic resistance of tangential swirlers with annular channels, velocity and pressure obtained experimentally and by calculation in a wide range of variation of the design parameters of the device are presented.
The dependences between the hydraulic resistance of the swirler and its design parameters are revealed.
Numerical simulation of the parameters of the gas flow in the channels is carried out. Diagrams of the pressure and velocity distribution are presented and analyzed, and experimental data on the influence of the design parameters of the swirler channel, such as width and length, on its hydraulic resistance are confirmed.
An empirical dependence for determining the hydraulic resistance coefficient of a tangential swirler with annular channels is presented for engineering calculations.
7
Voinov, Nikolaj Aleksandrovich, Anastasiya Viktorovna Bogatkova, Nina Vladimirovna Deryagina, Denis Andreevich Zemtsov i Nataliya Yul`evna Kozhukhova. "RESISTANCE OF TANGENTIAL SWIRLERS WITH ANNULAR CHANNELS". chemistry of plant raw material, nr 1 (10.03.2022): 335–42. http://dx.doi.org/10.14258/jcprm.2022019670.
Pełny tekst źródłaStreszczenie:
A review of vortex apparatuses and processes in which a rotating gas-liquid flow is used as an intensification of heat and mass transfer is presented.
It is shown that tangential swirlers, which are easy to manufacture and compact, have found the greatest application in industrial practice for creating gas (steam) rotation.
It is experimentally established that tangential swirlers with annular walls of channels intended for gas passage have the lowest hydraulic resistance.
The data on the hydraulic resistance of tangential swirlers with annular channels, velocity and pressure obtained experimentally and by calculation in a wide range of variation of the design parameters of the device are presented.
The dependences between the hydraulic resistance of the swirler and its design parameters are revealed.
Numerical simulation of the parameters of the gas flow in the channels is carried out. Diagrams of the pressure and velocity distribution are presented and analyzed, and experimental data on the influence of the design parameters of the swirler channel, such as width and length, on its hydraulic resistance are confirmed.
An empirical dependence for determining the hydraulic resistance coefficient of a tangential swirler with annular channels is presented for engineering calculations.
8
Thomas and, Luis, i Beatriz Marino. "Lock-Exchange Flows in Non-Rectangular Cross-Section Channels". Journal of Fluids Engineering 126, nr 2 (1.03.2004): 290–92. http://dx.doi.org/10.1115/1.1677475.
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Lock-exchange flows driven by density differences in non-rectangular cross-section channels are investigated in situations that resemble estuaries, navigation canals and hydraulic engineering structures. A simple analytical model considering stratified flows suggests practical relationships corroborated by results of laboratory experiments carried out in a straight channel of triangular cross-section.
9
Joldassov, S. К., S. T. Abildaev i S. J. Tattibaev. "ON METHODS FOR DETERMINING THE ROUGHNESS COEFFICIENT OF CHANNELS ALONG THE PERIMETER". Herald of the Kazakh-British technical university 20, nr 3 (4.10.2023): 76–88. http://dx.doi.org/10.55452/1998-6688-2023-20-3-76-88.
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The scientific article deals with the issues of uniform movement of the riverbed and the determination of the roughness coefficient of the riverbed (roughness coefficient). The analysis of existing methods for calculating the difference in the roughness coefficients of channels along the perimeter, methods for determining the roughness coefficient of the slopes of channels consisting of two or three parts along the perimeter, well–known scientists - P.N.Belokon, G.K.Lotter, N.N.Pavlovsky are given.There are a some varieties of calculation methods assigned for hydraulic calculations of water flow along the perimeter of a soil channel in the field of hydraulic engineering. A number of researchers states that the roughness of the channel bed imitates the motion of the flow in diverse channels with the movement of the flow under the ice layer. Nevertheless, it should be taken into account that the roughness of the channel bed has its own characteristic (specific) features of the movement of water in different open channels and below the ice cover. The common formulas proposed by number of authors for channels with different roughness along the perimeter cannot be used directly in hydraulic calculations of the flow under the ice cover, and vice versa, the equations of motion of water flow beneath the ice cover are not applied even for channels with various roughness along the perimeter. Therefore, the corresponding choice of methods for determining the roughness coefficients of the canal flow along the perimeter will be the key point to its long-term functioning.
10
Ortloff, Charles R. "Tipon: Insight into Inka Hydraulic Engineering Practice". Latin American Antiquity 30, nr 4 (grudzień 2019): 724–40. http://dx.doi.org/10.1017/laq.2019.70.
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The site of Tipon, Peru, located about 30 km east of Cuzco, provides an example of Inka knowledge of hydraulic engineering and the civil engineering practices used in the design and operation of the complex water system. The inhabitants of Tipon used river- and spring-sourced surface and subterranean channels to convey, distribute, and drain water to and from multiple agricultural platforms, reservoirs, and urban ceremonial centers. Intricate intersecting surface and subterranean channel systems that combined and regulated water flows from different sources controlled the water to and drainage from 13 terraced agricultural platforms. This design served to maintain different ground moisture levels to sustain specialty crops. Within the site are fountains and multiple water display features requiring sophisticated hydraulic engineering necessary for aesthetic displays. To understand the technology used by the Inka to design the water systems at Tipon, I used computational fluid dynamics methodology and modern hydraulic engineering theory. I made computer models of key elements of the Principal Fountain and the Main Aqueduct to reproduce water flow patterns in these features as intended by Inka engineers’ designs and calculations. The Inka hydraulic technology used complex engineering principles similar to those in modern civil engineering practice centuries ahead of their formal discovery in Western hydraulic science.
11
Borovkov, V. S., i M. Yurchuk. "Hydraulic resistance of vegetated channels". Hydrotechnical Construction 28, nr 8 (sierpień 1994): 432–38. http://dx.doi.org/10.1007/bf01487449.
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Baryshnikov, N. B., i A. F. Kudryashov. "Hydraulic resistances of river channels". Hydrotechnical Construction 33, nr 6 (czerwiec 1996): 347–52. http://dx.doi.org/10.1007/bf02764650.
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Baron, Alexander. "Determination of hydraulic resistance of channels using spectral geometry methods". Fluid Dynamics Research 53, nr 6 (1.12.2021): 065508. http://dx.doi.org/10.1088/1873-7005/ac44fa.
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Abstract In this paper, we propose a new method for calculation of hydraulic resistance of channels with constant cross-section. The method is based on the obtained estimates for the average energy dissipation rate in a turbulent flow. The first part of the paper is devoted to theoretical justification of the method. The second part is devoted to calculation of hydraulic resistance of various channels using the above-mentioned method and comparison of these values with the known results. The proposed method allows for calculation of hydraulic resistance of various channels with sufficiently high accuracy and is based only on the information about the channel geometry.
14
Astakhov, V. P., P. S. Subramanya i M. O. M. Osman. "Theoretical and Experimental Investigations of Coolant Flow in Inlet Channels of the BTA and Ejector Drills". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 209, nr 3 (czerwiec 1995): 211–20. http://dx.doi.org/10.1243/pime_proc_1995_209_075_02.
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The coolant flow through inlet annular channels in BTA and ejector drills is investigated. The study was conducted in order to understand the influence of the channel's parameters (the channel's clearance variation along its length and eccentricity) on the coolant pressure distribution and hydraulic resistance. A new design of the ejector drill with the eccentrical location on the inner tube is proposed. A study is made of the stability in the coolant flow in the inlet annular channels. The appearance of instability is explained by the presence of Taylor macrovortices in these channels under certain combinations of boring bar rotating velocity and axial flow velocity. In order to define the unstable regimes (the critical Reynolds numbers), the mathematical model for non-isothermal flow through the annular channel is solved. The heat transfer from the swarf to the incoming coolant is investigated under different flow conditions.
15
Gunal, Mustafa, i Rangaswami Narayanan. "Hydraulic Jump in Sloping Channels". Journal of Hydraulic Engineering 122, nr 8 (sierpień 1996): 436–42. http://dx.doi.org/10.1061/(asce)0733-9429(1996)122:8(436).
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Bayon-Barrachina, Arnau, i Petra Amparo Lopez-Jimenez. "Numerical analysis of hydraulic jumps using OpenFOAM". Journal of Hydroinformatics 17, nr 4 (13.03.2015): 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.
17
Yang, Zhuo, Wuquan He, Yubao Wang, Zongke Lou i Pinzhang Duan. "Research on the Comprehensive Optimization of the Hydraulic Performance and Frost-Heaving Resistance of a Parabolic Channel". Water 12, nr 9 (15.09.2020): 2574. http://dx.doi.org/10.3390/w12092574.
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Hydraulic performance and frost-heaving resistance should be considered simultaneously in the channel design of seasonally frozen soil areas. Quadratic parabolic channels have good water and sand transport capacities and high frost-heaving resistances. The width–depth ratio of a parabola determines its section structural form, which in turn determines the hydraulic performance and frost-heaving resistance. In this research, based on the current lack of a comprehensive optimization method that accounts for the hydraulic performance and frost-heaving resistance of the cross-section structures of parabolic channels, a multi-objective optimization model was established with the goal of achieving a minimum cross-sectional flow area and a uniform channel section force. Taking the flow velocity, the width–depth ratio and the crack resistance of concrete lining plate as constraints, the α method of the linear weighted sum method was used to optimize the calculation, and the comprehensive optimal quadratic parabolic channel section was obtained. The comprehensive optimal section of an actual parabolic channel in the Shijin Irrigation District was determined using this method, and the comprehensive optimal section was analyzed and compared to the original design section and two typical parabolic channel sections. The comprehensive optimal section was compared with the original design section in the Shijin Irrigation District. The force uniformity of the optimal section was 23.2% better, the hydraulic performance was 1.96% better, and the land use was 12.35% less. Compared with the values for the hydraulic optimal section, the maximum positive and negative bending moments of the comprehensive optimal section decreased by 5.6% and 11.89%, respectively, and the force uniformity increased by 7.62%. Additionally, compared with the values for the practical economic section, the force uniformity and the hydraulic performance of the comprehensive optimal section increased by 1.79% and 0.2%, respectively, and the land use decreased by 4.49%. Thus, the comprehensive optimal section met the engineering requirements and it could provide a reference for the design and selection of parabolic channels in seasonally frozen soil areas.
18
Huang, Zhipeng, Chenhao Du, Chenxu Wang, Qianran Sun, Yuepeng Xu, Lufang Shao, Bin Yu, Guoliang Ma i Xiangdong Kong. "Bionic Design and Optimization on the Flow Channel of a Legged Robot Joint Hydraulic Drive Unit Based on Additive Manufacturing". Biomimetics 9, nr 1 (31.12.2023): 13. http://dx.doi.org/10.3390/biomimetics9010013.
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The joint hydraulic drive unit (HDU) serves as a pivotal element in enabling the high-performance movements of legged robots. Functioning as the conduit linking the oil source and the actuator, the hydraulic flow channel significantly impacts actuator performance. Hence, optimizing the HDU flow channel becomes imperative, enhancing not only HDU efficiency but also the overall system performance. This paper introduces a novel approach by aligning the hydraulic flow channel of the joint HDU with the arteriovenous layout of the cardiac vascular system, departing from the conventional machining flow channel model. Through simulations determining the optimal range of the vascular branch radius and angle, this study guides the design optimization of the joint HDU flow channel. With the primary optimization goal of reducing pressure loss, the study compares simulation outcomes of various flow channel models—linear, variable excessive radius, and the multidimensional Bessel curve—tailored to suit the arrangement specifics of the joint HDU. Further validating these designs, the flow channels are fabricated using additive manufacturing for experimental verification. The integration of simulation analyses and pressure loss testing reveals a remarkable reduction of over 40% in pressure loss for the bionic flow channel compared to the conventional machining form. This empirical evidence strongly substantiates the bionic flow channel’s superior efficacy in pressure loss reduction. The findings presented herein offer valuable insights for the development of low-loss flow channels in joint HDUs, thereby presenting a new avenue for designing energy-efficient, high power-to-weight ratio legged robots.
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Shamohamadi, Behnam, i Ali Mehboudi. "Analyzing Parameters Influencing Scour Bed in Confluence Channels Using Flow3D Numerical Model". Civil Engineering Journal 2, nr 10 (30.10.2016): 529–37. http://dx.doi.org/10.28991/cej-2016-00000055.
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Channels junction is a phenomenon which is used in most of irrigating and drainage networks and in hydraulic engineering in general. In two channels junction, main and secondary channels encounter with each other and move to the channel downstream. Scour holes and sedimentation zones are created in channels bed. 3D simulation of scour hole created in these channels is influenced by various factors. The ratio of main channel width to secondary channel width is one of the most important influencing factors. This parameter is the main focus of the present research. In the present study, a model calibrated with laboratory results has been simulated. The numerical model results have revealed that decreasing the ratio of main channel width to secondary channel width causes the secondary channel flow encounters to the front wall of the secondary channel. Also, it leads to creating scour near the front wall and the main hole is drawn towards the wall. Furthermore, in the present research, topographical changes of the bed with running time of the numerical model for the middle channel axis has been extracted and presented.
20
Chang, Howard H. "Hydraulic Design of Erodible‐Bed Channels". Journal of Hydraulic Engineering 116, nr 1 (styczeń 1990): 87–101. http://dx.doi.org/10.1061/(asce)0733-9429(1990)116:1(87).
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Lee, Jong-Seok, i Pierre Y. Julien. "Downstream Hydraulic Geometry of Alluvial Channels". Journal of Hydraulic Engineering 132, nr 12 (grudzień 2006): 1347–52. http://dx.doi.org/10.1061/(asce)0733-9429(2006)132:12(1347).
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Belozerov, Vladimir I., i Aleksandr S. Gorbach. "Investigation of the critical heat flux in small-diameter channels". Nuclear Energy and Technology 7, nr 1 (30.03.2021): 73–78. http://dx.doi.org/10.3897/nucet.7.65754.
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The paper describes experimental studies into the hydrodynamics and heat exchange in a forced water flow in small-diameter channels at low pressures. The timeliness of the studies has been defined by the growing interest in small-size heat exchangers. Small-diameter channels are actively used in components of compact heat exchangers for present-day engineering development applications. The major difficulty involved in investigation of heat-transfer processes in small-diameter channels consists in the absence of common methodologies to calculate coefficients of hydraulic resistance and heat transfer in a two-phase flow. The channel size influences the heat exchange and hydrodynamics of a two-phase flow as one of the determining parameters since the existing internal scales (vapor bubble size, liquid droplet diameter, film thickness) may become commensurable with the channel diameter, this leading potentially to different flow conditions. It is evident that one cannot justifiably expect a change in the momentum and energy transfer regularities in single-phase flows as the channel size is reduced for as long as the continuum approximation remains valid. The authors have analyzed the experiments undertaken by Russian scientists to investigate the distribution of thermal-hydraulic parameters in channels with a small cross-section in the entire variation range of the flow parameters in the channel up to the critical heat flux conditions when the wall temperature increases sharply as the thermal load grows slowly. The experimental critical heat flux data obtained by Russian and foreign authors has been compared.
23
Saghir, Mohamad Ziad. "Thermo-Hydraulic Performance of Multiple Channels and Pin Fins Forming Convergent/Divergent Shape". Energies 15, nr 21 (27.10.2022): 7993. http://dx.doi.org/10.3390/en15217993.
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Heat enhancement has been addressed by studying flow in channels with different shapes. The present paper investigates a particular channel shape with divergent and convergent forms. Two configurations are addressed: wall channels and pin-fin walls forming divergent/convergent shapes. The flow is assumed to be in a laminar and steady-state condition. The numerical model investigated the heat enhancement for different flow rates represented by Reynolds numbers. The average Nusselt number and the performance evaluation criterion revealed that wall channels outperformed the pin-fin shape. The performance evaluation criterion is higher than 1 for the wall channels. The main reason for this is that the flow passes through and above the wall creating mixing. This flow configuration happened since the wall height is shorter than the test cavity height. It is important to emphasize that pin-fins forming convergent channels did not improve heat enhancement when compared to convergent channels. No significant variation in the pressure drop was detected.
24
Wang, Weishu, Juan Zhen, Weihui Xu, Jiawei Guo i Yuxin Zhai. "Numerical Study of Flow Field Optimization for Forebay and Suction Chamber to Solve the Vibration of Pumps in a Parallel Circulation Pumping Station". Machines 10, nr 8 (11.08.2022): 680. http://dx.doi.org/10.3390/machines10080680.
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The water inlet channel is an essential component of the thermal power plant’s circulating water system. It primarily arranges the water flow in the channel so that it is introduced into the pump room smoothly, steadily, and uniformly. Significantly, the operation state of the circulating water pump is impacted by the flow condition of the water inlet channel. The coal-fired generating set’s water input channel was chosen as the research object in this work, and the Computational Fluid Dynamics (CFD) Method was used to examine hydraulic issues impacting anomalous vibration of circulating pumps. Nine optimization options were also suggested, and the effects of the various plans on the water inlet channel’s flow state were examined—the simulation’s outcomes. The simulation’s findings indicate that the arc deflector can enhance the water entry channel’s flow pattern. The wall-attached bias flow of the suction chamber vanished, and the constant flow state is present around the pump’s bellmouth. The thermal power unit’s circulating water pump’s vibration was eliminated, and the circulating pump’s operating efficiency increased due to the curved deflector’s rectification procedures being implemented in the forebay. The study’s findings can guide the hydraulic performance optimization of channels for water inlets with similar sideways or high slopes.
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Zhu, Chenhui, Hongmei Zhang, Wanzhang Wang, Kang Li i Wanru Liu. "Robust control of hydraulic tracked vehicle drive system based on quantitative feedback theory". International Journal of Distributed Sensor Networks 16, nr 2 (luty 2020): 155014772090783. http://dx.doi.org/10.1177/1550147720907832.
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To improve the control precision of the drive system of hydraulic tracked vehicles, we established a mathematical model of the drive system based on the analysis of structural characteristics of the high-clearance hydraulic tracked vehicles and the dual-pump dual-motor drive system and developed a control strategy based on the quantitative feedback theory. First, the mutual independence of the two motor channels was achieved through channel decoupling. Then, the loop-shaping controller and the pre-filter were designed for the two channels. The result of a simulation experiment indicates that the proposed control method is very effective in suppressing external uncertainties and smoothening the speed-switching process of the hydraulic motor. Finally, an hydraulic tracked vehicle steering experimental test was carried out. The results show that under two different steering modes, the maximum standard deviation of the output speeds of the inner and outer motors of the hydraulic tracked vehicle is only 0.42, which meets the performance requirement on the hydraulic motor speed. The average steering track radii of the geometric centers of the inner and outer tracks are 1.828 and 0.033 m, respectively, and the relative errors are 1.56% and 3.19%, respectively. This demonstrates that the proposed control method achieves satisfactory results in the robust control of the hydraulic tracked vehicle drive system. It provides some references for the future control research of the hydraulic servo drive system of the high-clearance hydraulic tracked vehicles.
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Delis, Anargiros I., i Ioannis K. Nikolos. "Shallow Water Equations in Hydraulics: Modeling, Numerics and Applications". Water 13, nr 24 (15.12.2021): 3598. http://dx.doi.org/10.3390/w13243598.
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This Special Issue aimed to provide a forum for the latest advances in hydraulic modeling based on the use of non-linear shallow water equations (NSWEs) and closely related models, as well for their novel applications in practical engineering. NSWEs play a critical role in the modeling and simulation of free surface flows in rivers and coastal areas and can predict tides, storm surge levels and coastline changes from hurricanes and ocean currents. NSWEs also arise in atmospheric flows, debris flows, internal flows and certain hydraulic structures such as open channels and reservoirs. Due to the important scientific value of NSWEs, research on effective and accurate numerical methods for their solutions has attracted great attention in the past two decades. Therefore, in this Special issue, original contributions in the following areas, though not exclusively, have been considered: new conceptual models and applications; flood inundation and routing; open channel flows; irrigation and drainage modeling; numerical simulation in hydraulics; novel numerical methods for shallow water equations and extended models; case studies; and high-performance computing.
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Hosokawa, Y., T. Ootsuki i C. Niwa. "Channel Experiments on Coastal Water Purification by Porous Bed Using Crushed Stones". Water Science and Technology 26, nr 9-11 (1.11.1992): 2007–10. http://dx.doi.org/10.2166/wst.1992.0648.
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Large-scale model channels (30m long × 1m wide × 1.3m deep × 6 channels) were constructed for contact purification experiments for coastal saline water. Each channel was filled with crushed stones which were expected to be coated with natural biofilm. Effects of sedimentation and biological oxidation were observed for different hydraulic retention time (HRT: 1-5 hours) and different stone size (mean d: 10-100 mm). Hydraulic characteristics were also measured. The following was clear after five months' observation in autumn and winter, (a) biofilm was developed for saline (S: 1-2 %) and low COD (COD: 1-5 mg/l) influent, (b) SS was removed by 50-60 % though TOC by 10-20%, (c) effluent quality was clearer with longer HRT and smaller stones, but total removed weight was maximum at the channel of shortest HRT due to the high hydraulic loading(12m3) (d) permeability ranged between 5-20cm/s for bare stones and became smaller as clogging developed, (e) inclination of water surface was a good index for clogging detection.
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Hutli, Ezddin, i Ramadan Kridan. "Thermal-hydraulic analysis of light water reactors under different steady-state operating conditions, Part 2: Pressurized water reactor". Nuclear Technology and Radiation Protection 37, nr 4 (2022): 276–88. http://dx.doi.org/10.2298/ntrp2204276h.
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The 1-D computer code MITH was used in this paper to perform sub-channel thermal-hydraulic analyses of a typical (Westinghouse model) pressurized water reactor. Two typical channels, hot and average, with the same flow rate and pressure drop, were tested under steady-state operating conditions. In this analysis, the channel with the highest temperature is designated as the hot channel. For the calculations, the channel model was divided into 20 parts. The thermal-hydraulic performance of the tested reactor was affected by power distribution, power level, and coolant mass-flow rate. Temperature distribution profiles of the fuel element and coolant are obtained for the average and hottest channels. A critical heat flux qncr analysis is also carried out and the heat fluxes in both channels were calculated. The W-3 correlation is employed to examine qncr in the hottest channel. Some data from the pressurized water reactor typical data sheet were used as input data, while others were used to validate the code. The code faithfully reproduced the Westinghouse model reactor results, including coolant, cladding, centerline, and surface fuel temperatures, quality and local heat flux qnloc, qncr and minimum departure from nucleate boiling ratio.
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Qin, Binbin, Fulian He, Xiaobing Zhang, Xuhui Xu, Wei Wang, Liang Li i Chen Dou. "Stability and Control of Retracement Channels in Thin Seam Working Faces with Soft Roof". Shock and Vibration 2021 (13.09.2021): 1–12. http://dx.doi.org/10.1155/2021/8667471.
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To reduce the risk of roof falling and rib spalling during equipment retracement in thin coal seam faces with soft roofs, the 25070 working face of Xuehu Coal Mine was taken as the research object, and theoretical analysis, numerical simulation, and field practice methods were used. Under different space relationships between retracement channels and main roof fracture, the load of hydraulic supports was quantitatively analyzed. The relationship between the working resistance of the hydraulic support and the sinking rotation angle of the immediate roof was analyzed, and a reasonable time for the arrangement of the retracement channel was determined. The sublevel excavation technology and the combined support technology of roof anchor cables and coal rib anchors were proposed. The field application shows that the falling height and rate of movable prop of the hydraulic supports, working resistance of the hydraulic supports, and the roof subsidence all meet the requirements of safety production during the terminal mining period, and the surrounding rock control effect of retracement channel was determined to be good. The safe and efficient mining of the coal mine is ensured, and the research results can provide guidance for similar working faces.
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Chandrabalan, Lokesh, Markus Baier, Roberto Meloni, Marco Pieri, Luca Ammannato, Eugenio Del Puglia i Simone Carmignato. "Non-Destructive Assessment of the Functional Diameter and Hydrodynamic Roughness of Additively Manufactured Channels". Applied Sciences 13, nr 10 (11.05.2023): 5911. http://dx.doi.org/10.3390/app13105911.
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Metal additive manufacturing, particularly laser powder bed fusion, is increasingly used in the gas turbine industry for the fabrication of channels with small diameters for conformal cooling and flow passage applications. A critical challenge in this context lies in evaluating aspects such as the geometrical and hydraulic diameters, the effective area and the roughness on the internal surface of the channel that affects the flow functionality. This paper proposes a new method to evaluate the geometrical and functional equivalent diameters, i.e., the hydraulic diameter of cylindrical channels and the mean surface topography height on the internal channel surface, using X-ray computed tomography. The developed methods were validated with experimental flow tests, considering the mean surface topography height to be equivalent to the hydrodynamic sand grain roughness, thereby determining the hydraulic diameter and the associated effective area. The method is a much faster approach to determining the available hydraulic diameter compared to flow tests and offers the possibility of evaluating the internal surface characteristics, with discrepancies between the two approaches being less than ±3%.
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Tu, Yi, i Yu Zeng. "Numerical Study on Flow and Heat Transfer Characteristics of Supercritical CO2 in Zigzag Microchannels". Energies 15, nr 6 (13.03.2022): 2099. http://dx.doi.org/10.3390/en15062099.
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The zigzag channel is the uppermost channel type of an industrial printed circuit heat exchanger (PCHE). The effect of geometric properties on the flow and heat transfer performance of the channel is significant to the PCHE design and optimization. Numerical investigations were conducted on the flow and heat transfer characteristics of supercritical CO2 (sCO2) in semicircular zigzag channels by computational fluid dynamics method. The shear stress transfer (SST) k–ω model was used as turbulence model and the National Institute of Standards and Technology (NIST) real gas model with REFPROP database was used to evaluate the thermophysical parameters of sCO2 in this numerical method. The effectiveness of the simulation method is verified by experimental data. Thermal hydraulic performance for zigzag channels with different pitch lengths, bending angles, and hydraulic diameters are studied comparatively based on this numerical method, with the boundary conditions which cover the pseudocritical point. The comparison results show that reducing the bending angle and pitch length will strengthen the effect of boundary layer separation on the leeward side of the wall and enhance the heat transfer performance, but the pressure drop of the channel will also increase, and the decrease of channel hydraulic diameter is beneficial to the heat transfer enhancement, but it is not as significant as that of the straight channel.
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Roushangar, Kiyoumars, Reyhaneh Valizadeh i Roghayeh Ghasempour. "Estimation of hydraulic jump characteristics of channels with sudden diverging side walls via SVM". Water Science and Technology 76, nr 7 (24.05.2017): 1614–28. http://dx.doi.org/10.2166/wst.2017.304.
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Sudden diverging channels are one of the energy dissipaters which can dissipate most of the kinetic energy of the flow through a hydraulic jump. An accurate prediction of hydraulic jump characteristics is an important step in designing hydraulic structures. This paper focuses on the capability of the support vector machine (SVM) as a meta-model approach for predicting hydraulic jump characteristics in different sudden diverging stilling basins (i.e. basins with and without appurtenances). In this regard, different models were developed and tested using 1,018 experimental data. The obtained results proved the capability of the SVM technique in predicting hydraulic jump characteristics and it was found that the developed models for a channel with a central block performed more successfully than models for channels without appurtenances or with a negative step. The superior performance for the length of hydraulic jump was obtained for the model with parameters F1 (Froude number) and (h2—h1)/h1 (h1 and h2 are sequent depth of upstream and downstream respectively). Concerning the relative energy dissipation and sequent depth ratio, the model with parameters F1 and h1/B (B is expansion ratio) led to the best results. According to the outcome of sensitivity analysis, Froude number had the most significant effect on the modeling. Also comparison between SVM and empirical equations indicated the great performance of the SVM.
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Nalluri, C., A. Ab Ghani i A. K. S. El-Zaemey. "Sediment Transport over Deposited Beds in Sewers". Water Science and Technology 29, nr 1-2 (1.01.1994): 125–33. http://dx.doi.org/10.2166/wst.1994.0658.
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This paper is based on an extensive experimental investigation of bedload transport of noncohesive sediments at “limit deposition” in channels of circular and rectangular cross-section. The effect of permanent deposits on the invert of pipe channels on sediment carrying capacity and hydraulic resistance to flow is investigated. The sediment transport data from rectangular and pipe channels led to the development of empirical equations with high correlation coefficients. These equations showed the possibilities of their validity for either channel shape with the incorporation of appropriate shape parameters.
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Campisano, A., E. Creaco i C. Modica. "Experimental analysis of the Hydrass flushing gate and laboratory validation of flush propagation modelling". Water Science and Technology 54, nr 6-7 (1.09.2006): 101–8. http://dx.doi.org/10.2166/wst.2006.608.
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Periodical cleansing operations prove necessary inside sewer systems in order to reduce hydraulic and environmental problems owing to the accumulation of deposits on the bottom of channels. For this objective, new effective hydraulic devices based on the scouring effects of flushing waves have been recently set up and adopted in many sewer systems. In this paper, the results of an experimental and numerical investigation on the hydraulic operation of the Hydrass flushing gate are reported. The experimental analysis has been carried out using a laboratory channel and a reduced scale model of the gate, in order to characterise the flushing waves generated by the device. The numerical analysis has been performed using a mathematical model specifically developed for the simulation of flushing waves inside sewer channels. The comparison of numerical results and experimental data has allowed evaluation of the applicability under unsteady flow conditions of the outflow relations determined for the Hydrass gate in a previous investigation under steady flow conditions.
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Cao, Shuyou, i Donald W. Knight. "Design for Hydraulic Geometry of Alluvial Channels". Journal of Hydraulic Engineering 124, nr 5 (maj 1998): 484–92. http://dx.doi.org/10.1061/(asce)0733-9429(1998)124:5(484).
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Roushangar, Kiyoumars, i Roghayeh Ghasempour. "Evaluation of the impact of channel geometry and rough elements arrangement in hydraulic jump energy dissipation via SVM". Journal of Hydroinformatics 21, nr 1 (26.11.2018): 92–103. http://dx.doi.org/10.2166/hydro.2018.028.
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Abstract Rough bed channels are one of the appurtenances used to dissipate the extra energy of the flow through hydraulic jump. The aim of this paper is to assess the effects of channel geometry and rough boundary conditions (i.e., rectangular, trapezoidal, and expanding channels with different rough elements) in predicting the hydraulic jump energy dissipation using support vector machine (SVM) as a meta-model approach. Using different experimental data series, different models were developed with and without considering dimensional analysis. The results approved capability of the SVM model in predicting the relative energy dissipation. It was found that the developed models for expanding channel with central sill performed more successfully and, for this case, superior performance was obtained for the model with parameters Fr1 and h1/B. Considering the rectangular and trapezoidal channels, the model with parameters Fr1, (h2−h1)/h1, W/Z led to better predictions. It was observed that between two types of strip and staggered rough elements, strip type led to more accurate results. The obtained results showed that the developed models for the case of simulation based on dimensional analysis yielded better predictions. The sensitivity analysis results showed that Froude number had the most significant impact on the modeling.
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Wei, Hai, Kaiyun Tao, Yongqin Luo, Bingyue Song, Mingming Wang i Juncai Xu. "Hydraulic Prototype Observation Tests on Reconstructed Energy Dissipation Facilities". Applied Sciences 13, nr 10 (19.05.2023): 6216. http://dx.doi.org/10.3390/app13106216.
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In order to assess the effectiveness of reconstructed energy dissipation facilities (EDFs) in open channels at hydropower stations, hydraulic prototype observation (HPO) tests are conducted to investigate the characteristics of discharge flow and the dynamic response of hydraulic structures during sluice opening periods. While hydraulic model tests (HMTs) are commonly utilized in laboratory settings to study these characteristics, experimental conditions cannot fully replicate the real-world operations of such structures. HPO tests are employed to examine flow patterns, free water surface fluctuations, and pulsating pressure changes in open channels under varying flood discharge conditions (FDCs). Flow patterns in open channels are recorded via video; free water surface fluctuations are measured using total-station and laser rangefinder instruments; and pulsating pressure is monitored with pressure sensors and data collection systems. Flow pattern observations concentrate on addressing adverse water flow phenomena, such as turbulence, surging, and backflow. The examination of free water surface fluctuations aims to verify whether the height of the guide wall along the open channel fulfills the necessary requirements and assess the effectiveness of energy dissipation of the EDF. To comprehend the variations in pulsating pressure within the continuous sill and the base slab, nine measurement points were established across three sections perpendicular to the continuous sill’s axis on three distinct elevation levels. Additionally, three measurement points were positioned on the reinforced base slab along the open channel’s axis. The findings indicate that the impact on the continuous sill caused by discharging water is more severe when the discharge rate of a single sluice gate reaches 500 m3/s than in other FDCs. To ensure the safe operation of open channels during flood discharge, the discharge rate for each sluice gate should be reduced to 250 m3/s. The dominant pulsation induced by discharge flow falls within the low-frequency range, resulting in minimal adverse effects on the stilling basin and guide wall. The flow pattern within the stilling basin remains stable under various FDCs, with no significant adverse hydraulic phenomena observed. Parameters, including free water surface fluctuations and pulsating pressure variations, lie within acceptable ranges. These observations suggest that the arrangement of the reconstructed energy dissipation facilities is generally effective following technical reconstruction.
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Volgin, George. "The hydraulic resistance coefficient in the conditions of simultaneous effect of Re, Fr and Unknown node mfrac found in MathML fragment.$ {B \over h} $". E3S Web of Conferences 97 (2019): 05031. http://dx.doi.org/10.1051/e3sconf/20199705031.
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One of the most important tasks of engineering hydraulics is to determine the energy loss during the motion of the fluid flow. The study of the question of whether the patterns of hydraulic resistances are similar in a calm and turbulent flow is relevant in the design of hydraulic structures. In most cases, a turbulent regime of fluid motion is observed in various applications, but to date, the theory of turbulence is not considered complete. When designing hydraulic structures, inaccuracies in the existing calculation methods can lead to a decrease in the efficiency and reliability of the entire spillway structure as a whole. The need for an integrated approach to the analysis of the impact on the hydraulic resistance of various factors is noted (degree of spread $ \left( {{B \over h}} \right) $), the degree of turbulence (Re) and the degree of flow roughness (Fr)), which is not always provided by known dependencies and methods of calculation. On the basis of our own experimental data, a new formula for calculating the hydraulic resistance of turbulent flows in smooth channels was obtained. The functional dependence of the hydraulic resistance coefficient on the parameters $ \left( {{B \over h}} \right) $, Re and Fr is obtained.
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Wright, Lesley M., Wen-Lung Fu i Je-Chin Han. "Influence of Entrance Geometry on Heat Transfer in Rotating Rectangular Cooling Channels (AR=4:1) With Angled Ribs". Journal of Heat Transfer 127, nr 4 (30.03.2005): 378–87. http://dx.doi.org/10.1115/1.1860564.
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The effect of entrance geometry on the heat transfer in rotating, narrow rectangular cooling channels is investigated in this study. Both smooth channels and channels with angled ribs are considered with three different entrance conditions: fully developed, sudden contraction, and partial sudden contraction. The rectangular channel has as aspect ratio of 4:1, and it is oriented at 135° with respect to the plane of rotation. In the test section with angled ribs, the ribs are angled at 45° to the mainstream flow. The rib height-to-hydraulic diameter ratio e/Dh is 0.078, and the rib pitch-to-height ratio P/e is 10. The range of flow parameters includes Reynolds number (Re=5000–40,000), rotation number (Ro=0.0–0.302), and inlet coolant-to-wall density ratio (Δρ/ρ=0.12). The heat transfer at the entrance of the heated portion of the smooth channel is significantly enhanced with the sudden contraction and partial sudden contraction entrances. In the smooth rotating channels, the effect of the entrance geometry is also present; however, as the rotation number increases, the effect of the entrance geometry decreases. It was also found in this study that the sudden and partial sudden contraction entrances provide higher heat transfer enhancement than the fully developed entrance through the first three to four hydraulic diameters of the channels with angled ribs. Again, the effect of the entrance geometry is greater in the stationary channels with angled ribs than the rotating channels with ribs. In both stationary and rotating channels, the influence of the entrance geometry on the heat transfer is more apparent in the smooth channels than in the ribbed channels.
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Bekbasarov, I. I., i N. А. Shanshabayev. "ANALYSIS OF RESEARCH RESULTS AND APPLICATION OF PILES AS PART OF HYDRAULIC FACILITIES". Bulletin of Kazakh Leading Academy of Architecture and Construction 90, nr 4 (15.12.2023): 77–96. http://dx.doi.org/10.51488/1680-080x/2023.4-06.
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The review article analyzes the results of research and application of various types of pile structures as part of hydraulic structures, including hammered, bored, tongue-and-groove piles. The results of the analysis of the study of foreign and domestic experts have shown the effectiveness of the use of piles in hydraulic engineering. The applications of piles as anti-filtration curtains of dams, for blocking riverbeds, the base of trough channels, aqueducts, mooring, embankments, fencing, shore-strengthening and other hydraulic structures are described. The features of the work of various types of driven piles (prismatic, wedge-shaped, conical, tongue-and-groove) and pile foundations of various hydraulic structures (trough channels, aqueducts, mooring, embankments, fencing, shore-strengthening, etc.) are considered. structures). The use of bored piles in the construction of the base of various hydraulic structures is described. The overall dimensions of the well piles for the installation of drilling piles are given. The distinctive features of various hydraulic structures on pile foundations under the influence of static, dynamic and special loads are revealed. Methods for calculating the parameters of immersion, deformability, stability and bearing capacity of piles and pile foundations are considered, which allow taking into account the patterns of their joint work with hydraulic structures. The analysis of the study shows a number of positive examples of the use of piles as part of hydraulic structures: cost-effectiveness, manufacturability, quickness and efficiency, etc.
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Liu, Jie, Qing Song Wei, An Li, Cong Wang, Wen Ting He i Yu Sheng Shi. "Experimental Study on Micro-Pressure Hydraulic Characteristics of Drip Irrigation Emitters with Multiple Types of Channels". Advanced Materials Research 255-260 (maj 2011): 3553–57. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.3553.
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Reducing emitters’ working hydraulic pressure appropriately can cut down construction cost and running cost of the whole drip irrigation system. Reduction of the emitters’ working hydraulic pressure, however, will directly affect emitters’ hydraulic characteristics and anti-clogging property. In this study, experimental research into the hydraulic characteristics of multiple types of emitters under micro-pressure and compared the hydraulic characteristics with the ones under normal hydraulic pressure has been done. The experimental results showed that compensating emitters had poor water discharge uniformity at critical startup hydraulic pressure while non-compensating emitters, dripping arrows and dripping tape had consistent water discharge uniformity under micro-pressure and under normal pressure.
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Padmanabhan, M. "Hydraulic Jump In Non-Prismatic Rectangular Channels". Journal of Hydraulic Research 23, nr 4 (sierpień 1985): 386–89. http://dx.doi.org/10.1080/00221688509499348.
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Shcherbyna, I. "PRINCIPLES OF CONSTRUCTION OF THE GENERALIZED MATHEMATICAL MODEL OF THE HYDRAULIC EXTINGUISHER OF OSCILLATIONS OF THE PASSENGER CAR". Collection of scientific works of the State University of Infrastructure and Technologies series "Transport Systems and Technologies" 1, nr 38 (24.12.2021): 173–84. http://dx.doi.org/10.32703/2617-9040-2021-38-170-16.
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The study of the processes associated with the use of working fluids in the elements of hydraulic drives was preceded by studies of the unsteady periodic movement of the working fluid in the pipelines of hydraulic systems. Such processes take place in hydraulic drives and their elements, and are associated with the compressibility of the working fluid. The stability of the operation of hydraulic valves, which are supplied to hydraulic systems in order to maintain, within the required limits, pressures or flow rates, is also largely predetermined by non-stationary hydro mechanical processes occurring in the pipelines of these systems, channels and chambers of hydraulic devices. The peculiarities of the working processes of passive vibration dampers of passenger cars include the interaction of the working fluid with moving parts and its flow through the channels and through the calibrated holes with local artificial resistance. For in-depth analysis of changes in operating parameters, it is necessary to use a mathematical model that should reflect the processes that occur during the operation of the hydraulic device. In the presented article the generalized mathematical model of the hydraulic damper of fluctuations of the passenger car of the НЦ-1100 type is developed. This model takes into account the special operating conditions of the hydraulic shock absorber, which allows you to study the impact of operating parameters on the performance of the device.
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Akhmedova, N. R., i V. A. Naumov. "Calculation of the roughness of the Sheshupe riverbed according to hydrological yearbooks". IOP Conference Series: Earth and Environmental Science 1112, nr 1 (1.12.2022): 012127. http://dx.doi.org/10.1088/1755-1315/1112/1/012127.
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Abstract When conducting engineering hydrometeorological surveys, hydrological and hydraulic calculations are performed, in which an indicator characterizing the resistance of the channel to flow is taken into account. The integral characteristic of the hydraulic resistance of river channels is the roughness coefficient. In accordance with regulatory documents, the values of the roughness of the channel of the water body and the floodplain are taken according to the qualitative characteristics of the channel, which is subjective and can lead to significant errors in the calculations. The use in calculations of the roughness coefficient obtained as a result of single field measurements is inappropriate, since it can change throughout the year. This paper presents the results of studying the roughness of the Sheshupe river bed in different seasons of the year, and establishes the dependence of the roughness coefficient on dimensionless complexes (Froude and Reynolds numbers). The published data of measurements on the Sheshupe River (hydrological post in the village of Dolgoe) were used for the calculations.
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Wang, Xiukai, Yao Tang, Bo Huang, Tiantian Hu i Daosheng Ling. "Review on Numerical Simulation of the Internal Soil Erosion Mechanisms Using the Discrete Element Method". Water 13, nr 2 (13.01.2021): 169. http://dx.doi.org/10.3390/w13020169.
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Internal erosion can trigger severe engineering disasters, such as the failure of embankment dams and uneven settlement of buildings and sinkholes. This paper comprehensively reviewed the mechanisms of soil internal erosion studied by numerical simulation, which can facilitate uncovering the internal erosion mechanism by tracing the movement of particles. The initiation and development of internal erosion are jointly influenced by the geometric, mechanical, and hydraulic conditions, which determine the pore channels and force chains in soil. The geometric conditions are fundamental to erosion resistance, whereas the mechanical conditions can significantly change the soil erosion resistance, and the hydraulic conditions determine whether erosion occurs. The erosion process can be divided into particle detachment, transport, and clogging. The first is primarily affected by force chains, whereas the latter two are mostly affected by the pore channels. The stability of the soil is mainly determined by force chains and pore channels, whereas the hydraulic conditions act as external disturbances. The erosion process is accompanied by contact failure, force chain bending, kinetic energy burst of particles, and other processes due to multi-factor coupling.
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Ortloff, Charles R. "Water Engineering at Precolumbian AD 600–1100 Tiwanaku’s Urban Center (Bolivia)". Water 12, nr 12 (18.12.2020): 3562. http://dx.doi.org/10.3390/w12123562.
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The pre-Columbian World Heritage site of Tiwanaku (AD 600–1100) located in highland altiplano Bolivia is shown to have a unique urban water supply system with many advanced hydraulic and hydrological features. By use of Computational Fluid Dynamics (CFD) modeling of the city water system, new revelations as to the complexity of the water system are brought forward. The water system consists of a perimeter drainage channel surrounding the ceremonial center of the city. A network of surface canals and subterranean channels connected to the perimeter drainage channel are supplied by multiple canals from a rainfall collection reservoir. The perimeter drainage channel provides rapid draining of rainy season rainfall runoff together with aquifer drainage of intercepted rainfall; water collected in the perimeter drainage channel is then directed to the Tiwanaku River then on to Lake Titicaca. During the dry season aquifer drainage continues into the perimeter drainage channel; additional water is directed into the drainage channel from a recently discovered, reservoir connected M channel. Two subterranean channels beneath the ceremonial center were supplied by M channel water delivered into the perimeter drainage channel that served to remove waste from the ceremonial center structures conveyed to the nearby Tiwanaku River. From control of the water supply to/from the perimeter drainage channel during wet and dry seasonal changes, stabilization of the deep groundwater level was achieved—this resulted in the stabilization of monumental ceremonial structure’s foundations, a continuous water supply to inner city agricultural zones, water pools for urban use and health benefits for the city population through moisture level reduction in city ceremonial and secular urban housing structures.
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Beirami, M. K., i Mohammad R. Chamani. "Hydraulic Jumps in Sloping Channels: Sequent Depth Ratio". Journal of Hydraulic Engineering 132, nr 10 (październik 2006): 1061–68. http://dx.doi.org/10.1061/(asce)0733-9429(2006)132:10(1061).
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Sivakumar, Karthikeyan, N. Kulasekharan i E. Natarajan. "Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels". International Journal of Turbo & Jet-Engines 35, nr 2 (25.05.2018): 193–201. http://dx.doi.org/10.1515/tjj-2016-0032.
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Abstract Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.
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Fuchino, S., M. Furuse, N. Higuchi, M. Okano i K. Agatsuma. "Hydraulic Characteristics of Long Nitrogen Cooling Channels". IEEE Transactions on Appiled Superconductivity 14, nr 2 (czerwiec 2004): 1754–57. http://dx.doi.org/10.1109/tasc.2004.831069.
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Tsaplin, M. I., V. P. Shul'ga i V. G. Tabankov. "Heat exchange and hydraulic resistance in radial rotating channels". Journal of Engineering Physics 57, nr 4 (październik 1989): 1160–65. http://dx.doi.org/10.1007/bf00871131.
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