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1
Muhič, Simon, and Matej Štefanič. "NUMERICAL ANALYSIS OF AN AHMED BODY WITH DIFFERENT SOFTWARE PACKAGES." Journal of Energy Technology 10, no. 1 (2024): 11–21. https://doi.org/10.18690/jet.10.1.11-21.2017.
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In this article, the results of CFD simulations are compared using two different software packages for numerical fluid dynamics. The analysis is performed for an Ahmed body, for which the measurement results and a variety of numerical simulations are available in the literature. The results of the stationary CFD simulations with the RANS approach show a significant difference between the results obtained with the SolidWorks Flow Simulation 2014 software and ANSYS Fluent 16.2 software in the air flow analysis area from 10 m/s to 60 m/s. The difference in computational time is also apparent.
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Wang, Yang, Shufeng Yang, Feng Wang, and Jingshe Li. "Optimization on Reducing Slag Entrapment in 150 × 1270 mm Slab Continuous Casting Mold." Materials 12, no. 11 (2019): 1774. http://dx.doi.org/10.3390/ma12111774.
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To reduce slag entrapment in 150 × 1270 mm slab continuous casting molds at the Tang Steel Company, the effect of submerged entrance nozzle (SEN) depth and casting speed on the phenomenon was studied by computational fluid dynamics simulations. Then, the slag entrapment behavior in continuous casting molds, utilizing Large Eddy Simulation (LES) by coupling the volume of fluid (VOF) method, was also used. Finally, the effect of several common oils usually used to simulate slag in water modelling on slag entrapment was discussed and the water modelling results were used to validate the numerical simulation findings. The results showed that the optimum scheme is a submerged depth of SEN 90 mm and a casting speed of 1.6 m/min. Under optimal conditions, the maximum surface velocity is smallest (0.335 m/s) and the maximum slag entrapment ratio (0.44%) appears in the position of 0.1 m below the meniscus after 15 s. The water modelling results were in good agreement with the numerical simulation results.
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Luan, Yi Gang, Na Liu, Zheng Wei Ma, Zheng Heng Zhao, and Xiao Meng Pei. "Flow Field Research on an M-Beam Separator." Applied Mechanics and Materials 419 (October 2013): 165–70. http://dx.doi.org/10.4028/www.scientific.net/amm.419.165.
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The paper focuses on the resistance characteristic of a novel M-beam separator. Adopting the combination of experiment study and numerical simulation, we achieve that 2D simulation has the similar results as 3D in predicting resistance characteristic which provides the theoretical basis for next research. An M-beam separator model ten times larger than original one based on similitude principle was made for sake of flow field visualization research. The paper analyses flow field distribution of the amplifying M-beam separator by silk thread display technology and the experiment results are well consistent with 2D numerical simulation. The flow field distribution described here could serve as a reference for developing M-beam separator.
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Zhu, Chunyue, Yanbin Dou, Guohua Yu, et al. "Modeling the Impact of Wind Drag Coefficient on Wind-Driven Currents in Lake Taihu, China." Water 16, no. 20 (2024): 2985. http://dx.doi.org/10.3390/w16202985.
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The wind drag coefficient, Cd, has a great influence on the numerical results obtained from shallow lakes. To analyze the modeling impacts of Cd on wind-driven currents, a series of numerical simulations of Lake Taihu were conducted at three grid resolutions (800 m × 800 m, 400 m × 400 m, and 100 m × 100 m) using the empirical formulae of Flather (F76), Large and Pond (LP81), Large and Yeager (LY04), Andreas (A12), and Gao (G20). The G20 formula produced the optimum results of all the formulae for both the water level and velocity simulations; however, the grid resolution was found to have a significant influence on simulation in G20 cases. Thus, the G20 formula is only recommended when using a high-resolution grid to meet the accuracy requirements of analyzing wind-driven currents in the numerical modeling of Lake Taihu. A combination of the A12 formula and a coarse grid is preferred when taking computational efficiency into consideration.
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Giraud-Moreau, Laurence, Abel Cherouat, Jie Zhang, and Houman Borouchaki. "Comparison between an Advanced Numerical Simulation of Sheet Incremental Forming Using Adaptive Remeshing and Experimental Results." Key Engineering Materials 554-557 (June 2013): 1375–81. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1375.
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Recently, new sheet metal forming technique, incremental forming has been introduced. It is based on using a single spherical tool, which is moved along CNC controlled tool path. During the incremental forming process, the sheet blank is fixed in sheet holder. The tool follows a certain tool path and progressively deforms the sheet. Nowadays, numerical simulations of metal forming are widely used by industry to predict the geometry of the part, stresses and strain during the forming process. Because incremental forming is a dieless process, it is perfectly suited for prototyping and small volume production [1, 2]. On the other hand, this process is very slow and therefore it can only be used when a slow series production is required. As the sheet incremental forming process is an emerging process which has a high industrial interest, scientific efforts are required in order to optimize the process and to increase the knowledge of this process through experimental studies and the development of accurate simulation models. In this paper, a comparison between numerical simulation and experimental results is realized in order to assess the suitability of the numerical model. The experimental investigation is realized using a three-axis CNC milling machine. The forming tool consists in a cylindrical rotating punch with a hemispherical head. A subroutine has been developed to describe the tool path from CAM procedure. A numerical model has been developed to simulate the sheet incremental forming process. The finite element code Abaqus explicit has been used. The simulation of the incremental forming process stays a complex task and the computation time is often prohibitive for many reasons. During this simulation, the blank is deformed by a sequence of small increments that requires many numerical increments to be performed. Moreover, the size of the tool diameter is generally very small compared to the size of the metal sheet and thus the contact zone between the tool and the sheet is limited. As the tool deforms almost every part of the sheet, small elements are required everywhere in the sheet resulting in a very high computation time. In this paper, an adaptive remeshing method has been used to simulate the incremental forming process. This strategy, based on adaptive refinement and coarsening procedures avoids having an initially fine mesh, resulting in an enormous computing time. Experiments have been carried out using aluminum alloy sheets. The final geometrical shape and the thickness profile have been measured and compared with the numerical results. These measurements have allowed validating the proposed numerical model. References [1] M. Yamashita, M. Grotoh, S.-Y. Atsumi, Numerical simulation of incremental forming of sheet metal, J. Processing Technology, No. 199 (2008), p. 163 172. [2] C. Henrard, A.M. Hbraken, A. Szekeres, J.R. Duflou, S. He, P. Van Houtte, Comparison of FEM Simulations for the Incremental Forming Process, Advanced Materials Research, 6-8 (2005), p. 533-542.
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Saadi, Souad, and Abla Chaker. "A Numerical Simulation Approach for Sunspot Area Calculation." Engineering, Technology & Applied Science Research 8, no. 3 (2018): 3013–17. https://doi.org/10.5281/zenodo.1400594.
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The aim of this paper is the numerical simulation of the sunspot area (SSA) and its location on the walls and on the floor of a room with a single window facing south. The input parameters of the calculation code are the geometry of the cell located in the site of Ksar Challala (35.1 N, 2.19 E, 800 m) in Algeria for the 21st of March, June and December. The SSA is a function of the window’s area, the date and time, the orientation of the room, the altitude and the azimuth of the sun. The obtained results show that the western wall is affected by the sun in the morning, the eastern wall in the afternoon, the floor and the north wall in the middle of the day. By increasing the window area from 1 m<sup>2 </sup>to 2 m<sup>2</sup> we found that the SSA increases considerably.
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Němeček, Jiří, and Jiří Němeček. "NUMERICAL SIMULATION OF SLUMP FLOW TEST OF CEMENT PASTE COMPOSITES." Acta Polytechnica CTU Proceedings 30 (April 22, 2021): 58–62. http://dx.doi.org/10.14311/app.2021.30.0058.
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This study presents a numerical simulation of the mini-slump flow test performed on the Haegerman table, according to EN 1015-3. The two-dimensional axisymmetrical Volume of fluid (VOF) model is used for the calculation. Various scenarios with the different model set up and boundary conditions were calculated to show how the results are affected. Simulations with different lifting velocities were carried out and compared to the case with instantaneous demolding, which is commonly used in numerical simulations. Also, the effect on results is shown between noslip and specific shear boundary conditions on the mold. The results of simulations indicate that mold lifting should be considered in numerical modeling even if calculation time is highly prolonged. Lifting velocities should not exceed the value of 0.2 m/s in order to maintain laminar flow and stablecalculation.
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Putrananda, Musdika Bagas Satria, Aldias Bahatmaka, Widya Aryadi, Berliana Ayarent Puteri, and Christian Imanuel Hutagalung. "Numerical Analysis of Six Degrees of Freedom Motion Response of Trimaran Semi-Submersible Ship." Mekanika: Majalah Ilmiah Mekanika 24, no. 1 (2025): 61. https://doi.org/10.20961/mekanika.v24i1.99057.
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This study examines the motion response characteristics of a trimaran semi-submersible vessel, with a focus on its performance in tourism applications where passenger comfort is a primary concern. Using ANSYS AQWA simulation software, this analysis integrates diffraction and radiation theory with potential flow theory to evaluate the six degrees of freedom (surge, sway, heave, roll, pitch, and yaw) under various wave conditions, including different frequencies and directions based on the Joint North Sea Wave Project (JONSWAP) spectrum. Simulations were performed on waves with heading angles ranging from 0° to 180°. The simulation results were validated based on previous studies both experimentally and numerically. The results show that the sway peaks at 8 m/m for heading angles of 90°, while the surge reaches a maximum of 8 m/m at 0° and 180°. The heave motion resonates between 2.2 rad/s with a peak amplitude of 3 m/m at 90°. Pitch motion at heading angles of 0° reaches 40 °/m at 3.5-4 rad/s. Roll motion remained within acceptable limits (9 °/m), and yaw peaked at 13 °/m at 45° and 135°. These findings suggest that, although the trimaran exhibits stable performance in most motion responses, design improvements are necessary to mitigate excessive pitch motion and enhance passenger comfort in tourism applications.
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Fan, Yu Guang, and Ting Wei. "Numerical Simulation of Flow Process of Ammonium Persulfate Crystallizer." Advanced Materials Research 997 (August 2014): 396–400. http://dx.doi.org/10.4028/www.scientific.net/amr.997.396.
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The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.
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Yin, Chongzhi, Shin-ichiro Shima, Lulin Xue, and Chunsong Lu. "Simulation of marine stratocumulus using the super-droplet method: numerical convergence and comparison to a double-moment bulk scheme using SCALE-SDM 5.2.6-2.3.1." Geoscientific Model Development 17, no. 13 (2024): 5167–89. http://dx.doi.org/10.5194/gmd-17-5167-2024.
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Abstract. The super-droplet method (SDM) is a Lagrangian particle-based numerical scheme for cloud microphysics. In this work, a series of simulations based on the DYCOMS-II (RF02) setup with different horizontal and vertical resolutions are conducted to explore the grid convergence of the SDM simulations of marine stratocumulus. The results are compared with the double-moment bulk scheme (SN14) and model intercomparison project (MIP) results. In general, all SDM and SN14 variables show a good agreement with the MIP results and have similar grid size dependencies. The stratocumulus simulation is more sensitive to the vertical resolution than to the horizontal resolution. The vertical grid length DZ ≪ 2.5 m is necessary for both SDM and SN14. The horizontal grid length DX < 12.5 m is necessary for the SDM simulations. DX ≤ 25 m is sufficient for SN14. We also assess the numerical convergence with respect to the super-droplet numbers. The simulations are well converged when the super-droplet number concentration (SDNC) is larger than 16 super-droplets per cell. Our results indicate that the super-droplet number per grid cell is more critical than that per unit volume at least for the stratocumulus case investigated here. Our comprehensive analysis not only offers guidance on numerical settings essential for accurate stratocumulus cloud simulation but also underscores significant differences in liquid water content and cloud macrostructure between SDM and SN14. These differences are attributed to the inherent modeling strategies of the two schemes. SDM's dynamic representation of aerosol size distribution through wet deposition markedly contrasts with SN14's static approach, influencing cloud structure and behavior over a 6 h simulation. Findings reveal sedimentation's crucial role in altering aerosol distributions near cloud tops, affecting the vertical profile of cloud fraction (CF). Additionally, the study briefly addresses numerical diffusion's potential effects, suggesting further investigation is needed. The results underscore the importance of accurate aerosol modeling and its interactions with cloud processes in marine stratocumulus simulations, pointing to future research directions for enhancing stratocumulus modeling accuracy and predictive capabilities.
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Zhai, S., and P. Hu. "Experiment study and numerical simulation of hydrogen-air mixture combustion." Journal of Physics: Conference Series 2208, no. 1 (2022): 012014. http://dx.doi.org/10.1088/1742-6596/2208/1/012014.
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Abstract In this paper, hydrogen-air mixture combustion test was carried out with a cylindrical tank which has a diameter of 2 m and a height of 4 m. The ignitor was located at the lower part of the tank and the volume fraction of hydrogen in the mixed gas was 4.33 %, 5.17 %, 7.38 % and 10.02 % respectively. The computational fluid dynamics software Gasflow is used to simulate the experiment. The changes of pressure, gas temperature and hydrogen concentration in the tank after gas ignition were explored. The results show that when the volume fraction of hydrogen is less than 4 % cannot be ignited. When the volume fraction is above 8 %, hydrogen is consumed completely and the temperature and pressure increase significantly. In the process of combustion, the flame propagates upwards and sideways at the same time, but the upward propagation speed is obviously faster. The upward propagation speed of flame is 0.81 m/s when hydrogen concentration is 5.17 %, 7.38 % is 1.31 m/s, and 10.02 % is 2.63 m/s. The horizontal speed of flame is 0.08 m/s, 0.39 m/s and 0.62 m/s respectively.
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Han, Dongseop, and Wooseong Che. "Comparison of the Shear Modulus of an Offshore Elastomeric Bearing between Numerical Simulation and Experiment." Applied Sciences 11, no. 10 (2021): 4384. http://dx.doi.org/10.3390/app11104384.
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The most important item when indicating the mechanical properties of offshore elastomeric bearings is the shear modulus, and the method of measuring this is shown in EN 1337-3, a regulation related to offshore elastomeric bearings. In this work, we conducted an experimental and numerical study on an offshore elastomeric bearing to find its shear modulus. Shear modulus tests were conducted according to the procedure specified in EN 1337-3 Annex F, while simulations were performed using the finite element analysis (FEA) software, ANSYS. The main objective of this research work is to determine optimum analysis conditions for the simulation method that considers a nonlinear model for the elastomer material and predicts the experimental results accurately. We considered the Mooney–Rivlin (M-R) model that has two-parameter (2P), five-parameter (5P), and nine-parameter (9P) forms, depending on the number of terms in the series. We observed that the load-displacement graph is linear, and the percentage error between the results obtained with 2P and 5P M-R models is around 2.23% in the compression and 0.38% in the shear. The simulation results from 2P M-R model showed a good agreement with the experimental results with the correlation coefficient (R2) being 0.999 with an average error of about 2%. However, the deviation between the experimental and simulation results from the 9P M-R model is very high, with about 7%. Based on this study, we can say that the 2P M-R model can accurately predict the nonlinear behavior of hyperelastic material used in elastomer bearing. In addition, the shear modulus of elastic bearings for Class 3 Shore hardness was verified by comparing the numerical simulation values with those presented in EN 1337-3 Annex D.
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Huang, Xi Cheng, Yi Xia Yan, Wei Zhou Zhong, Yu Ze Chen, and Jian Shi Zhu. "A Numerical Method for Penetration into Concrete Target Using SPH-Lagrange Coupling Method." Advanced Materials Research 163-167 (December 2010): 1217–21. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1217.
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This paper demonstrates the application of both numerical simulation and empirical equation in predicting the penetration of a concrete target by an ogive-nosed projectile. The results from the experiment performed by Gran and Frew are used as a benchmark for comparison. In the numerical simulations a 3.0-caliber radius-head steel ogival-nose projectile with a mass of 47 kg is fired against cylindrical concrete target with a striking velocity of 315 m/s. In the simulation the smooth particles hydrodynamics SPH-Lagrange coupling method is applied to predict the maximum depth of penetration. For calculation of DoP and response of projectile the SPH-Lagrange method can give satisfactory results.
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De La Hoz, Jose Bermudez, Wojciech Rudy, and Andrzej Teodorczyk. "Numerical Simulation of the Transition to Detonation in a Hydrogen–Air Mixture Due to Shock Wave Focusing on a 90-Degree Wedge." Energies 18, no. 3 (2025): 619. https://doi.org/10.3390/en18030619.
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This study numerically explores the initiation of detonation through shock wave reflection and focusing on a 90-degree wedge in varying mixtures of hydrogen–air. The simulations were conducted using the ddtFoam code, an integral part of the OpenFOAM open-source Computational Fluid Dynamics (CFD) package of density-based code for solving the unsteady, compressible Navier–Stokes equations. The simulation results unveil three potential outcomes in the corner post-reflection: deflagrative ignition in the corner, deflagrative ignition with intermediate transient phases leading to a delayed transition to detonation in the trailing combustion zone close to the apex of the wedge, and ignition with an immediate transition to detonation, resulting in the formation of a detonation wave in the corner tip. In the experimental investigation, the transition velocity for the stoichiometric mixture stood at approximately 719 m/s. In contrast, the numerical simulation indicated a transition velocity of 664 m/s for the same stoichiometric mixture, reflecting a 5.5% decrease in velocity. Such an underestimation level of 5–8% by the simulation results was observed for mixtures of 25–45% H2 in air.
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Chen, Lei. "Comparisons of Explicit and Implicit Finite Element Methods for Sheet Metal Forming." Advanced Materials Research 936 (June 2014): 1836–39. http://dx.doi.org/10.4028/www.scientific.net/amr.936.1836.
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Sheet metal forming is one of the most commonly practiced fabrication processes in industry. Numerical simulations of the complex parts are possible by finite element method in the past thirty years. The most important problem of the simulation is the reliability of the model. Static implicit method (SI) and dynamic explicit method (DE) were used to simulation sheet metal forming process. It was found that simulation speed in dynamic explicit software has large effect on the simulation results. The best simulation speed is 5~10 m/s. Compared with the simulation and experimental results of thickness, draw-in and CPU time, the DE method is preferred.
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Buras, Paweł, and Wiesław Wiśniewolski. "Numerical Model of Fish Exploitation – structure and application." Fisheries & Aquatic Life 27, no. 2 (2019): 86–101. http://dx.doi.org/10.2478/aopf-2019-0010.
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Abstract Fisheries simulation models are tools used for forecasting the effects of exploitation and determining the directions of managing fisheries resources. The Numerical Model of Fish Exploitation (NMFE) and its capabilities were tested on a population of common bream, Abramis brama (L.) in a dam reservoir that is exploited by commercial and recreational fisheries. Based on the designated population parameters of N0, Fij, Mi, and ei and the size and structure of the common bream population in the reservoir, the model was used to examine hypothetical simulation variants of changes in fishing intensity E1 with nets and rods, changes in fishing intensity based on actual fishing effort with nets, changes in natural mortality, changes in the size of fish caught, and the impact of this on the size of the resources. Initial catches with nets and rods were calculated. Increasing fishing effort did not translate proportionally to increased catches, and the function was curvilinear. The results of simulations that reduced the intensity of fishing with nets and decreased catch sizes concurred with data from actual catches. Simulations of changes in natural mortality had various effects on the size of catches. Reducing parameter M did not impact the level of catches, while increasing parameter M reduced the size of catches significantly.
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Irawan, Yosua Heru, and Harianto Harianto. "Numerical Simulation of The Effect of Wind Velocity on The Diffuser Augmented Wind Turbines Performance." Journal of Energy, Mechanical, Material, and Manufacturing Engineering 4, no. 2 (2019): 73–82. https://doi.org/10.22219/jemmme.v4i2.9931.
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The study was conducted on GE 1.5 XLE wind turbine blades with a blade length of 4.32 m. This study uses a numerical simulation method with the help of ANSYS Workbench 19 software. Simulation is carried out at wind speeds of 3 m/s, 5 m/s, and 8 m/s. The DAWT (Difuser Augmented Wind Turbines) research model uses the same wind turbine blade as a conventional wind turbine model which is the same GE 1.5 XLE model. The size of the diffuser added to the construction of the wind turbine is 9 m in addition to flanged on the side of the inlet and outlet diffuser.Based on numerical simulations carried out, for wind speeds of 3 m/s, the highest increase in DAWT performance is 115.6%. For wind speeds of 5 m/s, the highest increase in DAWT performance is 99.2%. For wind speeds of 7 m/s, the highest increase in DAWT performance is 91.8%. Based on the simulation results it can be said that the addition of diffuser in the construction of wind turbines will produce effective performance at wind speeds of 3 m/s. The increase in DAWT performance is relatively small on TSR 1-4, and some even experience a decrease in performance. So that it can be said that DAWT is not suggested to be operated on a low TSR, DAWT is recommended to operate above TSR 5.
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Chen, Xiangjun, Zhen Huang, Lin Wang, Xiaozhen Dong, and Pengfei Cui. "Determination of the Height of Overburden Water-Conducting Fracture Zone in 215102 Working Face of Yue Nan Coal Mine." Geofluids 2022 (November 12, 2022): 1–14. http://dx.doi.org/10.1155/2022/3124374.
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In order to extract gas accurately in Yue Nan coal mine and prevent gas over limit and gas accidents, a combination of theoretical analysis and numerical simulation was used to investigate the height of the overburden caving zone and fracture zone in the working face, using 215102 working face as the engineering background. The results show three key strata in the 215102 working face, namely siltstone, sandy mudstone, and sandy mudstone. The empirical formula’s calculation results are in good accord with the findings of the theoretical analysis, which indicates that the height of the water-conducting fracture zone created by mining in 215102’s working face is 87.35 m. The plastic zone, stress distribution and displacement variation of the model overburden of the working face were analyzed separately in the numerical simulation. The results of the plastic zone simulation show that the caving zone’s maximum height is about 15.96 m, and the fracture zone’s maximum height is approximately 82.39 m. The stress distribution shows that the caving zone’s greatest height is around 13.65 m, while the fracture zone’s maximum height is roughly 77.24 m. The amount of overburden subsidence proves that the caving zone’s maximum height of about 10.08 m, and the fracture zone’s maximum height of approximately 82.69 m. The height of the overburden caving zone and fracture zone of 215102 working face are ultimately found to be 14.02 m and 76.42 m, respectively, based on theoretical analysis, empirical formula calculation, and numerical simulation findings.
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David, Marjorie, Christian Paul Allan, and Eric Cruz. "Numerical simulation of the 1994 tsunami in Calapan, Mindoro, Philippines using Delft3D." IOP Conference Series: Earth and Environmental Science 1091, no. 1 (2022): 012013. http://dx.doi.org/10.1088/1755-1315/1091/1/012013.
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A tsunami is a long-period sea wave caused by an earthquake, submarine landslide, or other disturbance such as meteor impact. A 7.1-magnitude earthquake on November 15, 1994 caused a tsunami that hit the coastal areas of Batangas, Quezon, and Mindoro in the Philippines, resulting to 78 deaths. In this study, the 1994 Mindoro tsunami was numerically simulated by modelling of the initial water surface generated by the ground rupture and propagating the tsunami wave towards the coastal areas. Based on the simulations, the generated tsunami wave has a height not exceeding 1.5 m above mean sea level and caused water runup heights in the coast of Calapan, Mindoro reaching 2.6 m. The results of the numerical simulation locally agree with the post-disaster measurements of Imamura et al. (1995) for the coast of Calapan, Mindoro, but the maximum runup levels recorded in the nearby Baco Islands were not obtained with acceptable accuracy. Further calibration of the numerical model is underway to improve the performance of the model.
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Al-Hashimy, Zahid Ibrahim, Hussain H. Al-Kayiem, Mohammad Shakir Nasif, and Abdalellah O. Mohmmed. "Numerical Simulation of the Transient Development of Slug Flow in Horizontal Pipes." Applied Mechanics and Materials 819 (January 2016): 300–304. http://dx.doi.org/10.4028/www.scientific.net/amm.819.300.
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Slug flow regime in two and multi-phase flow in pipes is a complicated flow phenomena representing challenge in the design of the piping system. In the present work, water/air two phase flow was modeled and simulated as 3 dimensional, transient, and incompressible flow using Volume of Fluid technique in STAR-CCM+ software. The simulation was conducted to predict and evaluate the air-water slug flow in a horizontal pipe with 0.16 m diameter and 7 m long. The superficial velocities for both phases were extracted from Baker chart slug zone. The results were validated against experimental bench marking referenced in Baker chart and the proposed VOF technique shows a good capability in simulating the development of the slug flow regime. This model could be utilized for simulation of various two phase flow regimes.
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Ding, Ziwei, Shaoyi Wang, Jinglong Liao, et al. "Reasonable Working-Face Size Based on Full Mining of Overburden Failure." Sustainability 15, no. 4 (2023): 3351. http://dx.doi.org/10.3390/su15043351.
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To improve production efficiency and prevent potential disasters in coal mines, comprehensive research methods such as similar simulation, numerical simulation, theoretical analysis, and on-site detection were used in this study. The migration characteristics of overburden rock under different working face lengths and development heights of water-conducting fracture zones were investigated via these methods in order to determine the reasonable length of the working face. The results show that the regularity of the development height of water-conducting fracture zones in similar simulations and numerical simulations is highly consistent, and the final stable values are 48 and 50 m. When the working face length was 300 m, the error between the simulated value and the value calculated from the formula dropped below 10% and exhibited a further decreasing trend; as a result, the working face length of 300 m was found to be the turning point for the development height of the water-conducting fracture zone to become stable. Based on the simulation results and mining damage theory, the critical size of the working face was 307.6 m, and the height of the water-conducting fracture zone was determined to be in the range of 45.5–60.5 m. The actual detection result of the height of the water-conducting fracture zone under the critical size of the working face was 55 m, which conforms to the law obtained from the simulation. Finally, the reasonable working face length under the geological conditions of a coal mine was determined to be 300–400 m. This study offers important reference value for determining the reasonable working face length under similar geological conditions, and may have significance for the sustainable development of coal resource mining.
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Donnelly, P. J., W. J. Ewens, and S. Padmadisastra. "Functionals of random mappings: exact and asymptotic results." Advances in Applied Probability 23, no. 3 (1991): 437–55. http://dx.doi.org/10.2307/1427616.
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A random mapping partitions the set {1, 2, ···, m} into components, where i and j are in the same component if some functional iterate of i equals some functional iterate of j. We consider various functionals of these partitions and of samples from it, including the number of components of ‘small' size and of size O(m) as m → ∞the size of the largest component, the number of components, and various symmetric functionals of the normalized component sizes. In many cases exact results, while available, are uniformative, and we consider various approximations. Numerical and simulation results are also presented. A central tool for many calculations is the ‘frequency spectrum', both exact and asymptotic.
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Shang, Shu Zhen, Jiao Jiao Wang, Gui Min Lu, Wan Ning Zhang, and Xiao Ling Tang. "Numerical Simulation of Thixo-Diecasting Al6061 Alloy Automobile Part." Advanced Materials Research 418-420 (December 2011): 1456–59. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.1456.
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Parameters of Bingham model had been verified according to the thermal simulation compression tests of semi-solid 6061 aluminum and the equations presented by Stefan. The effects of the mold filling temperature of semi-solid slurry of 6061 aluminum during thixo-diecasting were analyzed. The results showed that such conditions of the mold filling temperature about 625°C, the injection speed changing to 2 m/s from 0.4 m/s when 60% of die cavity had been filled, were ideal to gain solidification in sequence and beneficial to get fully filled semi-solid parts with clear contour. The thixo-diecasting experiments were performed under above optimized conditions.
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Schraml, K., B. Thomschitz, B. W. McArdell, C. Graf, and R. Kaitna. "Modeling debris-flow runout patterns on two alpine fans with different dynamic simulation models." Natural Hazards and Earth System Sciences Discussions 3, no. 2 (2015): 1397–425. http://dx.doi.org/10.5194/nhessd-3-1397-2015.
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Abstract. Predicting potential deposition areas of future debris-flow events is important for engineering hazard assessment in alpine regions. For this, numerical simulation models are commonly used tools. However, knowledge of appropriate model parameters is essential but often not available. In this study we use two numerical simulation models, RAMMS-DF (Rapid Mass Movement System – Debris Flow) and DAN3D (Dynamic Analysis of Landslides in Three Dimensions), to back-calculate two well-documented debris-flow events in Austria and to compare the range and sensitivity of input parameters for the Voellmy flow model. All simulations are based on the same digital elevation model with a 1 m resolution and similar initial conditions. Our results show that both simulation tools are capable of matching observed deposition patterns. The best fit parameter set of μ [–] and ξ [m s−2] range between 0.07–0.11 and 200–300 m s−2, respectively, for RAMMS-DF, and 0.07–0.08 and 300–400 m s−2, respectively, for DAN3D. Sensitivity analyses show a higher sensitivity of model parameters for the DAN3D model than for the RAMMS-DF model. This study shall contribute to the evaluation of realistic model parameters for simulation of debris-flows in steep mountain catchments and highlights the sensitivity of the models.
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Bychkov, O. P., I. Yu Mironyuk, I. A. Solntsev, G. A. Faranosov, and M. A. Yudin. "Analysis of aeroacoustic characteristics of a supersonic jet at designed conditions based on numerical simulation." Akustičeskij žurnal 70, no. 3 (2024): 110–24. http://dx.doi.org/10.31857/s0320791924030111.
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The work is devoted to the numerical simulation of aeroacoustic characteristics of a supersonic jet issuing from a Laval nozzle at the design Mach number M=2. The results of the large-eddy simulations (LES) are presented. Characteristics of mean jet flow and its fluctuations, as well as the characteristics of the far-field jet noise, including its azimuthal content, are obtained. The results of the simulation are compared with experimental data and their acceptable agreement is shown. It is concluded that there are various noise generation mechanisms in the considered jet.
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Shi, Xueqing, Daniel (Jian) Sun, Ying Zhang, Jing Xiong, and Zhonghua Zhao. "Modeling Emission Flow Pattern of a Single Cruising Vehicle on Urban Streets with CFD Simulation and Wind Tunnel Validation." International Journal of Environmental Research and Public Health 17, no. 12 (2020): 4557. http://dx.doi.org/10.3390/ijerph17124557.
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Transportation has become one of the primary sources of urban atmospheric pollutants and it causes severe diseases among city residents. This study focuses on assessing the pollutant dispersion pattern using computational fluid dynamics (CFD) numerical simulation, with the effect and results validated by the results from wind tunnel experiments. First, the wind tunnel experiment was carefully designed to preliminarily assess the flow pattern of vehicle emissions. Next, the spatiotemporal distribution of pollutant concentrations around the motor vehicle was modeled using a CFD numerical simulation. The pollutant concentration contours indicated that the diffusion process of carbon monoxide mainly occurred in the range of 0−2 m above the ground. Meanwhile, to verify the correctness of the CFD simulation, pressure distributions of seven selected points that were perpendicular along the midline of the vehicle surface were obtained from both the wind tunnel experiment and the CFD numerical simulation. The Pearson correlation coefficient between the numerical simulation and the wind tunnel measurement was 0.98, indicating a strong positive correlation. Therefore, the distribution trend of all pressure coefficients in the numerical simulation was considered to be consistent with those from the measurements. The findings of this study could shed light on the concentration distribution of platoon-based vehicles and the future application of CFD simulations to estimate the concentration of pollutants along urban street canyons.
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Tran, Minh, Zeeshan Memon, William Pao, and Fakhruldin M. Hashim. "Preliminary Results of Numerical Simulation of Slug Flow in a Regular T-Junction." MATEC Web of Conferences 225 (2018): 03001. http://dx.doi.org/10.1051/matecconf/201822503001.
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Excessive liquid carryover in T-junction due to splitting nature of two-phase flow causes serious issues in piping system. A three-dimensional numerical model is employed to investigate two-phase flow split behavior of slug flow in a circular-section regular T-junction with 0.0752 m diameter. The Volume of Fraction method combined with k-ε turbulence model and initial sinusoidal perturbation in ANSYS FLUENT is adopted to characterize the effect of slug flow behavior on the phase separation efficiency. The preliminary result reveals that the simulation work can study slug flow split in great detail and the slug characteristic plays an important role in understanding split behavior.
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Jiang, Tianchi, and Weijun Zhang. "Numerical Simulation of Multi-Physics Fields in Fused Magnesia Furnace." Metals 13, no. 1 (2022): 39. http://dx.doi.org/10.3390/met13010039.
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In this paper, a 3D transient multi-physical field model is developed to capture the complex processes inside a fused magnesia furnace. The multi-physics model integrates electromagnetism, thermodynamics, decomposition reactions, and flow. The three-phase submerged magnesia furnace includes an arc, magnesite ores, a melting pool, and a solidification ingot. For a more comprehensive analysis of the optimal design of industrial operations, the influence of the key index of electrode insertion depth on temperature and reaction is also discussed. The results show that the current density in the fused magnesia furnace is almost the same as the joule heat distribution, and there is an obvious area of low energy density affected by the skin effect, which leads to the waste of electric energy. The temperature at the center of the arc reaches 12,000 K, and the plasma areas formed at the end of the three electrodes are connected to each other to form a closed current path, which provides energy for the process of melting magnesia. The arc region is an ellipsoid with a length of ~30 mm and a diameter of ~49 mm. The decomposition reaction of magnesite mainly occurs in the arc area, and the radiation heat provided by the high-temperature arc is used as the heat source. There is almost no magnesite in the molten pool, and the molten pool only provides energy for the melting process of magnesia. When the electrode insertion depth is 0.4, 0.5, 0.6, and 0.7 m, the arc length is 0.049 m, 0.066 m, 0.068 m, and 0.059 m, respectively. According to the simulation results, there is an optimal electrode insertion depth.
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Wang, Zi Fang, Ye Bin Yin, Wei Ji, et al. "Numerical Simulation Research on the Internal Flow of a Heat Exchanger." Applied Mechanics and Materials 694 (November 2014): 200–204. http://dx.doi.org/10.4028/www.scientific.net/amm.694.200.
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Spiral tube exchanger is one of the most important heat transfer devices among the electric water boilers. In this paper, CFD software is introduced to simulate the process of the flow of the spiral tube exchanger. Cases with different inlet velocities of the cold water have been conducted and results show that, temperature increment of the cold water reaches 38.87 K, 20.21 K and 12.12 K with the inlet velocity of the cold water set as 0.05 m/s, 0.09 m/s and 0.13 m/s respectively.
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Cheban, Egor Yu, and Andrey N. Luchkov. "Numerical simulation of compound wings wind tunnel test for wig effect vehicle." Russian Journal of Water Transport, no. 75 (June 19, 2023): 108–17. http://dx.doi.org/10.37890/jwt.vi75.358.
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This paper presents the comparison of numerical simulation results and wind tunnel experiment for compound WIG's wing. Numerical simulation was performed in the ANSYS Fluent software. The choice of the turbulence model and the computational mesh parameters, including the resolution of the boundary layer, are substantiated. Comparison of the results of the experiment and numerical simulation showed good convergence for middle density mesh about 7 million cells and first layer height 0.0001 m. Additional study for k-ε realizable and k-ω SST turbulence models was done. Its result founded much efficiency k-ε realizable model than k-ω SST turbulence models for compound WIG's wing. Numerical simulation takes less time and ensures the same accuracy. The results can be argued that the selected parameters of numerical simulation can be used to obtain the aerodynamic characteristics of various layout solutions for "type C" WIG craft.
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Anabor, V., U. Rizza, G. A. Degrazia, and E. de Lima Nascimento. "Numerical modelling of microburst with Large-Eddy Simulation." Atmospheric Chemistry and Physics Discussions 10, no. 10 (2010): 24345–70. http://dx.doi.org/10.5194/acpd-10-24345-2010.
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Abstract. An isolated and stationary microburst is simulated using a 3-D time-dependent, high resolution Large-Eddy Simulation (LES) model. The microburst downdraft is initiated by specifying a simplified cooling source at the top of the domain near 2 km. The modelled time scale for this damaging wind (30 m/s) is of order of few min with a spatial scale enclosing a region with 500 m radius around the impact point. These features are comparable with results obtained from full-cloud models. The simulated flow shows the principal features observed by Doppler radar and others observational full-scale downburst events. In particular are observed the expansion of the primary and secondary cores, the presence of the ring vortex at the leading edge of the cool outflow, and finally an accelerating outburst of surface winds. This result evidences the capability of LES to reproduce complexes phenomena like a Microburst and indicates the potential of LES for utilization in atmospheric phenomena situated below the storm scale and above the microscale, which generally involves high velocities in a short time scale.
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Pîrvu, Cătălin, Andreea Elena Musteată, George Ghiocel Ojoc, and Lorena Deleanu. "Numerical and Experimental Results on Charpy Tests for Blends Polypropylene + Polyamide + Ethylene Propylene Diene Monomer (PP + PA + EPDM)." Materials 13, no. 24 (2020): 5837. http://dx.doi.org/10.3390/ma13245837.
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This paper presents results from numerical and experimental investigation on Charpy tests in order to point out failure mechanisms and to evaluate new polymeric blends PP + PA6 + EPDM. Charpy tests were done for initial velocity of the impactor of 0.96 m/s and its mass of 3.219 kg and these data were also introduced in the finite element model. The proposed model takes into account the system of four balls, including support and the ring of fixing the three balls and it has a finer discretization of the impact area to highlight the mechanisms of failure and their development in time. The constitutive models for four materials (polypropylene with 1% Kritilen, two blends PP + PA6 + EPDM and a blend PA6 + EPDM) were derived from tensile tests. Running simulations for each constitutive model of material makes possible to differentiate the destruction mechanisms according to the material introduced in the simulation, including the initiation and the development of the crack(s), based on equivalent plastic strain at break (EPS) for each material. The validation of the model and the simulation results were done qualitatively, analyzing the shape of broken surfaces and comparing them to SEM images and quantitatively by comparing the impact duration, energy absorbed by the sample, the value of maximum force during impact. The duration of the destruction of the specimen is longer than the actual one, explainable by the fact that the material model does not take into account the influence of the material deformation speed in Charpy test, the model being designed with the help of tests done at 0.016 m/s (1000 mm/min) (maximum strain rate for the tensile tests). Experimental results are encouraging for recommending the blends 20% PP + 42% PA6 + 28% EPDM and 60% PA6 + 40% EPDM as materials for impact protection at low velocity (1 m/s). Simulation results are closer to the experimental ones for the more brittle tested materials (with less content of PA6 and EPDM) and more distanced for the more ductile materials (with higher content of PA6 and EPDM).
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Rinaldi, Weriono Weriono, Adi Isra, and Ajar Darmawan. "Numerical Modification of Piping Systems to Increase Flow Velocity in Receiving Facilities." JOURNAL OF MECHANICAL ENGINEERING MANUFACTURES MATERIALS AND ENERGY 8, no. 1 (2024): 11–19. http://dx.doi.org/10.31289/jmemme.v8i1.10254.
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The process of unloading avtur via bridger capacity of 24 KL through the piping system at the DPPU SSK II receiving facility takes 55-60 minutes with an average unloading flow rate is 27 m3/hour while the pump flow rate specification used is 60 m3/hour. In the process of unloading avtur through a piping system, there are various kinds of fitting. Where in the operation of the piping system can result losses caused by pipe roughness, pipe length, flow capacity, and components installed in the system. This study aims to determine the total head, minor and major losses of the piping system using the Darcy-Weisbach equation in mathematical calculation methods and simulations in the pipe flow expert software, the result of simulations will be compared with mathematical calculations to modify the piping system so can be obtained for increasing the flow rate of fluid flow to speed up the unloading process of avtur via bridger. The results of this study are: 1.) The total head value of the receiving piping system using the calculation method is 16.51 m while using a flow expert simulation is 12.9 m. 2.) The results of mathematical calculations of the energy equation for the piping system at the receiving facility obtained a flow rate of 55.2 m3/hour. 3.) From the results of system modifications by increasing the flow rate capacity to 80 m3 / hour and the pump head achieved 16.05 m, According to the simulation results of the software flow expert, pumping flow rate increase of 72 m3/ hour.
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Denisiewicz, Arkadiusz, Tomasz Socha, Krzysztof Kula, Wojciech Macek, Wojciech Błażejewski, and Grzegorz Lesiuk. "Numerical Determination of the Load-Bearing Capacity of a Perforated Thin-Walled Beam in a Structural System with a Steel Grating." Applied Sciences 14, no. 4 (2024): 1505. http://dx.doi.org/10.3390/app14041505.
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This article presents the results of numerical simulations of a structural system consisting of steel perforated thin-walled beams and a steel grating. The simulations were conducted using the finite element method. The analysis took into account physical and geometric nonlinearity as well as the contact between the steel grating and the beams. The main goal of the research was to develop load-bearing curves for the main beam in the span range of 3–6 m and to identify destruction patterns depending on the span of the structural system. For the purpose of validating the developed numerical model, laboratory tests were conducted on two structural systems with spans of 3 m and 6 m, as well as tests on the strength parameters of the material taken from the tested beams. The laboratory tests confirmed the correctness of the proposed numerical model, which allowed for the simulation of the behavior of the structural system in the full range of spans.
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Asghar, Usama, Muzaffar Ali, Danyal Iqbal, Muhammad Ali, and Muhammad Hassan Ameer. "Numerical Analysis of dew point Indirect Evaporative Cooler." MATEC Web of Conferences 381 (2023): 01007. http://dx.doi.org/10.1051/matecconf/202338101007.
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An indirect evaporative cooler that uses a Maisotsenko (M) Cycle has the potential to be a green and sustainable solution for managing a building’s cooling demand since it can attain sub-wet bulb temperature without humidification. This study presents the design and simulation analysis of a crossflow indirect evaporative cooler using the COMSOL Multiphysics software for various ambient conditions. The cooler’s performance was evaluated by varying the inlet air temperatures. The analysis was conducted using numerical simulations, and the outcomes were compared with experimental data. The simulation results demonstrated that the cooler could achieve significant temperature reductions at a minor energy consumption as compared to traditional air conditioning systems. This study delivers that this system reduces the temperature of inlet air up to 22°C as well as cooling capacity and coefficient of performance values are 3.699 kW and 27.40. Overall, the results demonstrate the potential of crossflow indirect evaporative coolers as an energy-efficient alternative to conventional air conditioning systems.
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Nguyễn, Xuân Bàng, Viết Chinh Mai, Đức Tiệp Phạm та Hoàng Long Nguyễn. "Mô phỏng số ứng xử của tấm bê tông dưới tác động của tia nước tốc độ cao". Vietnam Institute for Building Science and Technology 2025, vi.vol1 (2025): 12–19. https://doi.org/10.59382/j-ibst.2025.vi.vol1-2.
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The high-pressure water jet technology has been widely applied in the construction industry. However, understanding the complicated interactions between high-velocity water jets and concrete surfaces remains a significant challenge. This paper employs a numerical simulation method using the Coupled Eulerian-Lagrangian (CEL) technique to analyze the behavior of concrete slabs under the impact of high-velocity water jets. The study focuses on the pressure distribution at the impact zone and the deformation characteristics of concrete under water jet velocities ranging from 100 m/s to 1000 m/s. The results indicate that the maximum pressure at the impact zone ranges from 0.13 GPa to 1.6 GPa, concentrated at the center and gradually decreasing outward. The findings provide critical data for practical applications in the concrete structures subjected to high-velocity water jet impacts.
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Stacy, Athena, Christopher F. McKee, Aaron T. Lee, Richard I. Klein, and Pak Shing Li. "Magnetic fields in the formation of the first stars – II. Results." Monthly Notices of the Royal Astronomical Society 511, no. 4 (2022): 5042–69. http://dx.doi.org/10.1093/mnras/stac372.
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ABSTRACT Beginning with cosmological initial conditions at z = 100, we simulate the effects of magnetic fields on the formation of Population III stars and compare our results with the predictions of Paper I. We use gadget-2 to follow the evolution of the system while the field is weak. We introduce a new method for treating kinematic fields by tracking the evolution of the deformation tensor. The growth rate in this stage of the simulation is lower than expected for diffuse astrophysical plasmas, which have a very low resistivity (high magnetic Prandtl number); we attribute this to the large numerical resistivity in simulations, corresponding to a magnetic Prandtl number of order unity. When the magnetic field begins to be dynamically significant in the core of the minihalo at z = 27, we map it on to a uniform grid and follow the evolution in an adaptive mesh refinement, MHD simulation in orion2. The non-linear evolution of the field in the orion2 simulation violates flux-freezing and is consistent with the theory proposed by Xu & Lazarian. The fields approach equipartition with kinetic energy at densities ∼1010–1012 cm−3. When the same calculation is carried out in orion2 with no magnetic fields, several protostars form, ranging in mass from ∼1 to 30 M⊙; with magnetic fields, only a single ∼30 M⊙ protostar forms by the end of the simulation. Magnetic fields thus suppress the formation of low-mass Pop III stars, yielding a top-heavy Pop III initial mass function and contributing to the absence of observed Pop III stars.
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Xie, Jing, Yi Tang, Jin Feng Wang, Chen Miao, and Yue Zhao. "Numerical Simulation on Comparison of Air Flow Distribution with Different Algorithms." Applied Mechanics and Materials 220-223 (November 2012): 2716–20. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.2716.
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To get the air distribution in a small cold store, a mini type cold store ( 4. 5 m ( l)×3. 3 m (w )×2. 5 m (h) ) was referenced. The model of the small cold store was established in the software named GAMBIT and after this the three-dimensional numerical simulation was used. The different simulation result was verified by the experiments. The accuracy of simulation in airflow field in cold stores was studied by comparison of various mesh rezoning, various decoupling methods for airflow speed and pressure. The results showed that 10cm dimensional accuracy was the suitable mesh size for the calculation speed without affecting the simulation accuracy, and the SIMPLE algorithm was better for the PISQ algorithms to simulate steady air flow of the cooling process in a cold store without products. It was concluded that there was a large circumfluence in the flow field, the speeds in the center and corner were lower than those in other places. The distribution of flow speed in the horizontal plane had a good symmetrical, however that in the vertical plane was lower than that in the center, but higher upwards and downwards. The study validated 3D CFD simulation technology for the small cold store. The results of the research offered the optimized methods of using CFD and acted as the reference of the simulation model in the cold store.
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Donnelly, P. J., W. J. Ewens, and S. Padmadisastra. "Functionals of random mappings: exact and asymptotic results." Advances in Applied Probability 23, no. 03 (1991): 437–55. http://dx.doi.org/10.1017/s0001867800023673.
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A random mapping partitions the set {1, 2, ···,m} into components, whereiandjare in the same component if some functional iterate ofiequals some functional iterate ofj. We consider various functionals of these partitions and of samples from it, including the number of components of ‘small' size and of sizeO(m) asm→ ∞the size of the largest component, the number of components, and various symmetric functionals of the normalized component sizes. In many cases exact results, while available, are uniformative, and we consider various approximations. Numerical and simulation results are also presented. A central tool for many calculations is the ‘frequency spectrum', both exact and asymptotic.
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Aliiev, Elchyn, and Petro Bezverkhniy. "Numerical Simulation of a Pneumatic Precision Seed Drill." National Interagency Scientific and Technical Collection of Works. Design, Production and Exploitation of Agricultural Machines, no. 52 (2022): 86–98. http://dx.doi.org/10.32515/2414-3820.2022.52.86-98.
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As a result of numerical simulation of the seed retarder of the John Deere pneumatic seed drill in the software package Star CCM + visualization of the process of seed movement and air flow in the working area of the retarder was obtained. According to the results of numerical modeling and processing of data obtained in the software package Wolfram Mathematica obtained third-order regression equations in decoded form without significant coefficients according to Student's t-test dependences of air flow rate Vaout, seed speed Vpout the velocity of the air flow at the inlet Vain and the ratio of the area of the outlets to the area of the inlet ε. As a result of solving the compromise method of scalar ranking by minimizing the multiplicative function taking into account the coefficient of importance of the private criterion at fixed values of air flow velocity at the inlet Vain in the range from 5 m/s to 25 m/s seed. It is established that at the specified range of air flow rate at the inlet Vain it is necessary to adjust the seeding rate by the coefficient η, which is in honey from 1.47 to 2.56.
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Liu, Ze Hua, Yan Liao, and Hao Ping Yu. "Indoor Thermal Environment Research of Air Conditioning Office with Air from Window Gap." Advanced Materials Research 860-863 (December 2013): 1660–65. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1660.
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The paper presents a numerical simulation study of indoor thermal environment of an air conditioning office in winter in Hengyang. Considering the effect of air infiltration from window gap, the distribution of indoor temperature field, velocity field and humidity field can be obtained when air supply angle is 45° down to the horizontal direction. Compared with simulation which air infiltration is ignored, the results show that average temperature of air conditioning area reduces 0.6 °C in Y = 1.1 m section. Air velocity is larger in Y = 1.1 m air conditioning zone. The air speed is greater than 0.2 m/s in local area, a sense blowing. Average relative humidity is larger in Y = 1.1 m air conditioning area. The research indicates that air infiltration can not be allowed to be neglected in numerical simulation.
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Fan, Dingfan, Min Yu, Zhixiang Yao, Yang Du, and Hang Liu. "A Method for Real-Time Measurement of the Vertical Vortex at Flood Discharge Outlets Using Ultrasonic Sensors." Sensors 24, no. 17 (2024): 5583. http://dx.doi.org/10.3390/s24175583.
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In this study, ultrasonic sensors were used to measure the vertical vortex at flood discharge outlets in real time, and numerical simulations and model experiments were conducted. When a sound signal passes through a vortex, its propagation characteristics will change, which helps to determine the existence of the vortex. Moreover, its characteristic parameters can be obtained through inversion. In this paper, first, the theories of acoustic measurement methods were introduced and their feasibility was verified through a comparison between Particle Image Velocimetry (PIV) measurement and numerical simulation results. Then, the Computational Fluid Dynamics (CFD) method was used to simulate the vertical vortex at the flood discharge outlets of hydraulic structures and the simulation data were restored to the actual size at scale. Finally, acoustic numerical simulations of actual vortex data were conducted, and ultrasonic sensors were used to measure the velocity of a simplified vertical vortex model under laboratory conditions. The research results indicate that the acoustic measurement method proposed in this article is effective in the measurement of the characteristic parameters of vertical vortex with a core radius of 0.03~0.05 m and a maximum tangential velocity of 0.5 m/s, the measurement error of the maximum tangential velocity is within 10%.
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Zeng, Cheng, Yimo Bai, Jie Zhou, et al. "Large Eddy Simulation of Compound Open Channel Flows with Floodplain Vegetation." Water 14, no. 23 (2022): 3951. http://dx.doi.org/10.3390/w14233951.
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Floodplain vegetation is of great importance in velocity distribution and turbulent coherent structure within compound open channel flows. As the large eddy simulation (LES) technique can provide detailed instantaneous flow dynamics and coherent turbulent structure predictions, it is of great importance to perform LES simulations of compound open channel flows with floodplain vegetation. In the present study, a wall-modeled large eddy simulation (WMLES) method was employed to simulate the compound open channel flows with floodplain vegetation. The vegetation-induced resistance effect was modeled with the drag force method. The WMLES model, incorporating the drag force method, was verified against flume measurements and an analytical solution of vegetated open channel flows. Numerical simulations were conducted with a depth ratio of 0.5 and four different floodplain vegetation densities (frk = 0, 0.28 m−1, 1.13 m−1 and 2.26 m−1). The main flow velocity, secondary flow, bed shear stress and vortex coherent structure, based on the Q criterion, were obtained and analyzed. Based on the numerical results, the influences of floodplain vegetation density on the flow field and turbulent structure of compound open channel flows were summarized and discussed. Compared to the case without floodplain vegetation, the streamwise velocity in the main channel increased by 10.8%, 19.9% and 24.4% with the frk = 0.28 m−1, 1.13 m−1 and 2.26 m−1, respectively. The results also indicated that, when the floodplain vegetation density increased, the following occurred: the velocity increased in the main channel, while the velocity decreased in the floodplain; the transverse momentum exchange was enhanced; and the strip structures were more concentrated near the junction area of compound open channel flows.
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Cheng, Wang, Zhang Chentian, Li Shuo, and Li Jianhua. "Study on Sunshine Stress Effect of Long-Span and Wide Concrete Box Girder." International Journal of Photoenergy 2022 (May 31, 2022): 1–7. http://dx.doi.org/10.1155/2022/8149765.
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In order to further clarify the sunshine stress effect of long-span and wide concrete box girder, the study selected a concrete box girder with 4 × 42 m span and 33.5 m width, formed the temperature field load through a field test and numerical simulation, established a numerical analysis model by using the finite element program of ANSYS, and comprehensively analyzed the longitudinal temperature stress distribution of a long-span and wide concrete box girder under sunshine. The midspan section of the first span of the box girder is selected for field stress measure, and the field measure results and numerical analysis results are compared and analyzed. The research shows that the results of field measurement and numerical simulation are basically consistent. Sunshine temperature has a great influence on long-span and wide concrete box girder, which should be paid enough attention.
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Fu, Qiang, Weixin Pang, Mingqiang Chen, and Sheng Pang. "Laboratory-Scale Natural Gas Hydrate Extraction Numerical Simulation Under Phase Transition Effect." Energies 18, no. 3 (2025): 755. https://doi.org/10.3390/en18030755.
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Phase transition in gas hydrate reservoirs has a significant effect on the fluid flow dynamic when performing test production, which should be carefully studied. This study systematically investigates the phase transition characteristics of natural gas hydrates during the depressurization extraction process through laboratory-scale numerical simulations. First, a laboratory-scale numerical simulation model is established with dimensions of 1 m × 1 m × 1 m. In the simulation, the nanoscale and microscale effect on phase transition is considered. Then, the analysis of how different sediment types and their properties affecting gas production dynamics is presented. The results show that hydrate dissociation and formation are significantly influenced by factors such as the pore scale, salinity, and water content. In particular, montmorillonite had the most significant effect, leading to a 525.25% increase in gas production, while the impact of silty soil was relatively smaller. The increase in salinity inhibited hydrate formation but promoted dissociation, resulting in a significant increase in gas production, especially when the salinity reached to 3.5%, where gas production increased by 590.21%. An increase in water content led to a significant decrease in production. Through monitoring temperature and pressure changes during the extraction process, the different physical fields are analyzed, providing important theoretical support and practical guidance for the efficient extraction of natural gas hydrates.
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Ding, Li, Xiaohui Gu, Peihui Shen, Xiangsheng Kong, and Yi Zhou. "Dynamic Response of UHMW-PE Composite Armors under Ballistic Impact of Blunt Projectiles." Materials 15, no. 16 (2022): 5594. http://dx.doi.org/10.3390/ma15165594.
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To study the dynamic response of UHMW-PE composite armor under ballistic impact, two kinds of UHMW-PE composite armors are designed. Both of them are composed of UHMW-PE laminates and steel face sheets of Q235. The blunt projectile is made of 35CrMnSiA, with a cylinder shape. By numerical simulation, the dynamic response and deformation of composite armors are obtained under the penetration of the projectile. With the increase of impact velocity, the penetration depth increases nearly linearly, with a more severe tendency of swaging in the projectile. Then, experiments are carried out to validate the numerical simulation results. Based on a ballistic gun with a caliber of 14.5 mm, the projectiles are fired with a velocity from 680 m/s to 1300 m/s. The penetration into the composite armor can be divided into an initial shear plugging stage and the following bulging and delamination stage. Based on the theoretical analysis, the shear strength in the shear plugging stage can be estimated. Associated with typical experimental results, numerical simulation is suitable to predict the bulging characteristics of the composite armor. The failure mode of the composite armors under the impact of blunt projectiles is determined, and the failure mechanism is analyzed. The penetration results in the experiment agree well with the numerical simulation results, which validate the correctness of the numerical simulation models. The research results can be significant in the design of composite armor with UHMW-PE laminates.
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Wu, Jun, Zhaoli Zheng, Zhenxing Zhao, Yong Li, and Weijian Lv. "Numerical Simulation Research on Vibration Isolation Performance of Concrete Foundation Platform." Journal of Physics: Conference Series 2557, no. 1 (2023): 012089. http://dx.doi.org/10.1088/1742-6596/2557/1/012089.
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Abstract The simulation analysis model of the concrete experimental foundation platform is constructed by the method of three-dimensional computer-aided design (3D CAD) and three-dimensional computer-aided engineering (3D CAE). The influence of the slotting depth and width on the concrete structure’s vibration isolation performance is analyzed in detail. The results show that as the slotting depth increases from 0 m to 4 m, the total vibration acceleration level of the concrete inner side structure decreases by 12.27 dB. The vibration isolation performance of the foundation platform is highly sensitive to the slotting depth. As the slotting width increases from 0.5 m to 2 m, the total vibration acceleration level of the concrete inner side structure is always maintained within the range of 8.8 dB–8.9 dB. The total vibration acceleration level of the foundation platform changes little. Vibration isolation performance shows low sensitivity to the slotting width.
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Hasankhani, Arezoo, James VanZwieten, Yufei Tang, et al. "Modeling and Numerical Simulation of a Buoyancy Controlled Ocean Current Turbine." International Marine Energy Journal 4, no. 2 (2021): 47–58. http://dx.doi.org/10.36688/imej.4.47-58.
Full textAbstract:
Increased global renewable power demands and the high energy density of ocean currents have motivated the development of ocean current turbines (OCTs). These compliantly mooring systems will maintain desired near-surface operating depths using variable buoyancy, lifting surface, sub-sea winches, and/or surface buoys. This paper presents a complete numerical simulation of a 700 kW variable buoyancy controlled OCT that includes detailed turbine system, inflow, actuator (i.e., generator and variable buoyancy), sensor, and fault models. Simulation predictions of OCT performance are made for normal, hurricane, and fault scenarios. Results suggest this OCT can operate between depths of 38 m to 329 m for all homogeneous flow speeds between 1.0-2.5 m/s. Fault scenarios show that rotor braking results in a rapid vertical OCT system assent and that blade pitch faults create power fluctuations apparent in the frequency domain. Finally, simulated OCT operations in measured ocean currents (i.e., normal and hurricane conditions) quantify power statistics and system behavior typical and extreme conditions.
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Yasin, Seyab, Sultan Salem, Hamdi Ayed, Shahid Kamal, Muhammad Suhail, and Yousaf Ali Khan. "Modified Robust Ridge M-Estimators in Two-Parameter Ridge Regression Model." Mathematical Problems in Engineering 2021 (September 22, 2021): 1–24. http://dx.doi.org/10.1155/2021/1845914.
Full textAbstract:
The methods of two-parameter ridge and ordinary ridge regression are very sensitive to the presence of the joint problem of multicollinearity and outliers in the y-direction. To overcome this problem, modified robust ridge M-estimators are proposed. The new estimators are then compared with the existing ones by means of extensive Monte Carlo simulations. According to mean squared error (MSE) criterion, the new estimators outperform the least square estimator, ridge regression estimator, and two-parameter ridge estimator in many considered scenarios. Two numerical examples are also presented to illustrate the simulation results.
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Liu, Jiajia, Jianliang Gao, Ming Yang, Dan Wang, and Liang Wang. "Numerical Simulation of Parameters Optimization for Goaf Gas Boreholes." Advances in Civil Engineering 2019 (January 10, 2019): 1–13. http://dx.doi.org/10.1155/2019/3891080.
Full textAbstract:
In view of the ground drilling of the N2206 working face in Shanxi Wangzhuang Coal Mine, the gas concentration is low and the extraction effect is not good. Fluent computational fluid dynamics software was used to simulate the ground extraction drilling position of the N2206 working face in the goaf (the distance from the top of the coal seam and the distance from the return to the wind). The numerical simulation results show that when the final hole of the ground extraction hole in the goaf is 16 m from the roof of the coal seam and the distance from the return air is 45 m, the extraction effect is optimal. The average extraction gas volume is 9.78 m3/min, and the average extraction gas concentration is 43.95%, the best extraction effect is obtained. After optimizing the ground drilling position in the goaf and combining with the site implementation, the maximum gas scouring amount of the extraction is 12.59 m3/min, which is 3.42 m3/min higher than the original. The maximum gas concentration of extraction was 63.54%, which was 28.82% higher than the original. After optimization, the gas concentration of the extraction is more than 30%, and the extraction effect is very good. Field application results further validate the reliability of theoretical analysis and numerical simulation results.