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Comparison of Reynolds average Navier-Stokes turbulence models in numerical simulations of the DC arc plasma torch 被引量:2
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作者 Zihan PAN Lei YE +4 位作者 Shulou QIAN Qiang SUN Cheng WANG Taohong YE Weidong XIA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第2期60-72,共13页
Five turbulence models of Reynolds average Navier-Stokes(RANS),including the standard k-ω model,the RNG k-e model taking into account the low Reynolds number effect,the realizable k-ω model,the SST k-ω model,and th... Five turbulence models of Reynolds average Navier-Stokes(RANS),including the standard k-ω model,the RNG k-e model taking into account the low Reynolds number effect,the realizable k-ω model,the SST k-ω model,and the Reynolds stress model(RSM),are employed in the numerical simulations of direct current(DC)arc plasma torches in the range of arc current from 80 A to 240 A and air gas flow rate from 10 m^3 h^-1 to 50 m^3 h^-1.The calculated voltage,electric field intensity,and the heat loss in the arc chamber are compared with the experiments.The results indicate that the arc voltage,the electric field,and the heat loss in the arc chamber calculated by using the standard k-ω model,the RNG k-ωmodel taking into account the low Reynolds number effect,and the realizable k-ω model are much larger than those in the experiments.The RSM predicts relatively close results to the experiments,but fails in the trend of heat loss varying with the gas flow rate.The calculated results of the SST k-ω model are in the best agreement with the experiments,which may be attributed to the reasonable predictions of the turbulence as well as its distribution. 展开更多
关键词 DC arc plasma torch numerical simulation turbulence model
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Modeling and Numerical Simulation of Wings Effect on Turbulent Flow between two contra-rotating cylinders 被引量:1
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作者 Maher Raddaoui 《Journal of Modern Physics》 2011年第5期392-397,共6页
Many industries in the world take part in the pollution of the environment. This pollution often comes from the reactions of combustion. To optimize these reactions and to minimize pollution, turbulence is a funda- me... Many industries in the world take part in the pollution of the environment. This pollution often comes from the reactions of combustion. To optimize these reactions and to minimize pollution, turbulence is a funda- mental tool. Several factors are at the origin of turbulence in the complex flows, among these factors, we can quote the effect of wings in the rotating flows. The interest of this work is to model and to simulate numeri- cally the effect of wings on the level of turbulence in the flow between two contra-rotating cylinders. We have fixed on these two cylinders eight wings uniformly distributed and we have varied the height of the wings to have six values from 2 mm to 20 mm by maintaining the same Reynolds number of rotation. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses (Reynolds Stress Model: RSM). We have modelled wings effect on the flow by a source term added to the equation tangential speed. The results of the numerical simulation showed that all the average and fluctuating variables are affected the value of the kinetic energy of turbulence as those of Reynolds stresses increase with the height of the wings. 展开更多
关键词 Pollution turbulence Combustion WING modelING numerical simulation Contra-Rotating Cylinders REYNOLDS Stress model Source TERM
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Direct numerical simulation of viscoelastic-fluid-based nanofluid turbulent channel flow with heat transfer 被引量:2
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作者 阳倦成 李凤臣 +2 位作者 蔡伟华 张红娜 宇波 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期404-420,共17页
Our previous experimental studies have confirmed that viscoelastic-fluid-based nanofluid(VFBN) prepared by suspending nanoparticles in a viscoelastic base fluid(VBF, behaves drag reduction at turbulent flow state) can... Our previous experimental studies have confirmed that viscoelastic-fluid-based nanofluid(VFBN) prepared by suspending nanoparticles in a viscoelastic base fluid(VBF, behaves drag reduction at turbulent flow state) can reduce turbulent flow resistance as compared with water and enhance heat transfer as compared with VBF. Direct numerical simulation(DNS) is performed in this study to explore the mechanisms of heat transfer enhancement(HTE) and flow drag reduction(DR) for the VFBN turbulent flow. The Giesekus model is used as the constitutive equation for VFBN. Our previously proposed thermal dispersion model is adopted to take into account the thermal dispersion effects of nanoparticles in the VFBN turbulent flow. The DNS results show similar behaviors for flow resistance and heat transfer to those obtained in our previous experiments. Detailed analyses are conducted for the turbulent velocity, temperature, and conformation fields obtained by DNSs for different fluid cases, and for the friction factor with viscous, turbulent, and elastic contributions and heat transfer rate with conductive, turbulent and thermal dispersion contributions of nanoparticles, respectively. The mechanisms of HTE and DR of VFBN turbulent flows are then discussed. Based on analogy theory, the ratios of Chilton–Colburn factor to friction factor for different fluid flow cases are investigated, which from another aspect show the significant enhancement in heat transfer performance for some cases of water-based nanofluid and VFBN turbulent flows. 展开更多
关键词 viscoelastic-fluid-based nanofluid direct numerical simulation thermal dispersion model turbulent drag reduction heat transfer e
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Modeling and Numerical Simulation of Wings Effect on Turbulent Flow between Two Contra-Rotating Discs 被引量:1
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作者 M. Raddaoui 《Journal of Energy and Power Engineering》 2011年第1期42-47,共6页
Turbulence is a fundamentally interesting physical phenomenon which is of fundamental interest. Indeed, it is at the origin of several industrial applications, the control of energy in these industrial applications pa... Turbulence is a fundamentally interesting physical phenomenon which is of fundamental interest. Indeed, it is at the origin of several industrial applications, the control of energy in these industrial applications pass by the comprehension and the modelling of turbulent flows. Several factors are at the origin of turbulence in the complex flows, among these factors, we can quote the effect of wings in the rotating flows. The interest of this work is to model and to simulate numerically the effect of wings on the level of turbulence in the flow between two contra-rotating discs. We have fixed on these two discs eight wings uniformly distributed and we have varied the height of the wings to have eleven values from 0 to 18 mm by maintaining the same Reynolds number of rotation. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses (Reynolds Stress Model: RSM). We have modelled wings effect on the flow by a source term added to the equation tangential speed. The results of the numerical simulation showed that all the average and fluctuating variables are affected the value of the kinetic energy of turbulence as those of Reynolds stresses increase with the height of the wings. 展开更多
关键词 turbulence control of energy WING modelING numerical simulation contra-rotating discs Reynolds Stress model source term.
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Solution of Self-similar Equations of the k-ε Model in the Shear Turbulent Mixing Problem and Its Numerical Simulation
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作者 Vyacheslav P. Statsenko Yulia V. Tret'yachenko Yury V. Yanilkin 《Journal of Physical Science and Application》 2015年第6期377-395,共19页
The paper presents the k-ε model equations of turbulence with a single set of constants chosen by the authors, which is appropriate to simulate a wide range of turbulent flows. The model validation has been performed... The paper presents the k-ε model equations of turbulence with a single set of constants chosen by the authors, which is appropriate to simulate a wide range of turbulent flows. The model validation has been performed for a number of flows and its main results are given in the paper. The turbulent mixing of flow with shear in the tangential velocity component is discussed in details. An analytical solution to the system of ordinary differential equations of the k-ε model of turbulent mixing has been found for the self-similar regime of flow. The model coefficients were chosen using simulation results for some simplest turbulent flows. The solution can be used for the verification of codes. The numerical simulation of the problem has been performed by the 2D code EGAK using this model. A good agreement of the numerical simulation results with the self-similar solution, 3D DNS results and known experimental data has been achieved. This allows stating that the k-ε model constants chosen by the authors are acceptable for the considered flow. 展开更多
关键词 The k-ε model of turbulent mixing shear turbulent mixing self-similar equations numerical simulation.
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Numerical Simulation on Gas-Solid Two-Phase Turbulent Flow in FCC Riser Reactors(Ⅱ) Numerical Simulation on the Gas-Solid Two-Phase Turbulent Flow 被引量:1
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作者 高金森 徐春明 +2 位作者 林世雄 郭印诚 王希麟 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1998年第1期25-32,共8页
Numerical simulation on the flow,heat transfer and cracking reactions in commercial fluid catalyticcracking(FCC)riser reactors were carried out employing the developed turbulent gas-solid two-phase flow-reac-tion mode... Numerical simulation on the flow,heat transfer and cracking reactions in commercial fluid catalyticcracking(FCC)riser reactors were carried out employing the developed turbulent gas-solid two-phase flow-reac-tion model for FCC riser reactors given in Part Ⅰ of the present paper.Detailed information about the turbulentflow fields in the riser reactor obtained revealed the basic characteristics of the gas-solid two-phase turbulentflows when heat transfer and catalytic cracking reactions were co-existing in the riser.Results showed that thedistributions of the flow,the turbulence kinetic energy and the catalyst particle concentration are not uniform inthe axial,radial and tangential directions.The most complicated part of the riser reactor is the feed injectingzone.The complicated configuration of the turbulent gas-solid two-phase flows would exert a great influence onthe results of interphase heat transfer and cracking reactions. 展开更多
关键词 commercial RISER REACTOR flow-reaction model turbulent FLOW numerical simulation FLOW field
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Optimization of flow control devices for a T-type five-strand billet caster tundish: water modeling and numerical simulation 被引量:11
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作者 Fei He Ling-ying Zhang Qi-Yan Xu 《China Foundry》 SCIE 2016年第3期166-175,共10页
The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare... The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare tundish and tundish conf igurations with designed U-type baff les and a round turbulence inhibitor were analyzed using residence time distribution(RTD) curves. Mathematical models for liquid steel in the real plant tundish were established using the fluid dynamics software package Fluent. The flow field, the temperature field, and the RTD curves of liquid steel in the proposed tundish conf igurations were obtained. The results of numerical simulation and water modeling were validated with each other by the predicted and experimental RTD curves. The results of flow field and temperature field were used to ref lect the actual state of a real plant tundish and to choose the optimal FCD. Finaly, from the whole performance of the multi-strand tundish, the optimal scheme was determined by combining the results of water modeling and numerical simulation. With the optimal tundish equipped with U-type baffle with def lector holes and round turbulence inhibitor, not only was the flow characteristic of each strand improved, but also the difference of flow characteristics between multiple strands was smaller. 展开更多
关键词 TUNDISH water modeling numerical simulation RTD BAFFLE turbulence inhibitor
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AN EXTENDED k-ε MODEL FOR NUMERICAL SIMULATION OF WIND FLOW AROUND BUILDINGS
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作者 陈水福 孙炳楠 唐锦春 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1998年第1期95-100,共6页
It is assumed in this paper that for a high Reynolds number nearly homogeneouswind flow, the Reynolds stresses are uniquely related to the mean velocity gradientsand the two independent turbulent scaling parameters k ... It is assumed in this paper that for a high Reynolds number nearly homogeneouswind flow, the Reynolds stresses are uniquely related to the mean velocity gradientsand the two independent turbulent scaling parameters k and E. By applying dimensionalanalysis and owing to the Cayley-Hamilton theorem for tensors, a new turbulenceenclosure model so-called the axtended k-ε model has been developed. The coefficientsof the model expression were detemined by the wind tunnel experimental data ofhomogeneous shear turbulent flow. The model was compared with the standard k-εmodel in in composition and the prediction of the Reynold's normal Stresses. Using thenew model the numerical simulation of wind flow around a square cross-section tallbuilding was performed. The results show that the extended k-ε model improves theprediction of wind velocities around the building the building and wind pressures on the buildingenvelope. 展开更多
关键词 turbulence model Reynolds stress wind flow numerical simulation
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Experiment and numerical simulation of two-phase flow in oxygen enriched side-blown furnace 被引量:16
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作者 Yan-ting LIU Tian-zu YANG +3 位作者 Zhuo CHEN Zhen-yu ZHU Ling ZHANG Qing HUANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第1期249-258,共10页
Taking an oxygen enriched side-blown furnace as the prototype,a hydraulic model was established according to the similarity principle.The influence of three factors on the gas-liquid two-phase flow was analyzed,i.e.th... Taking an oxygen enriched side-blown furnace as the prototype,a hydraulic model was established according to the similarity principle.The influence of three factors on the gas-liquid two-phase flow was analyzed,i.e.the airflow speed,the submerged depth and the downward angle of the nozzle.A numerical simulation of the hydraulic model was carried out trying to find the suitable turbulence model which can describe the side-blown two-phase flow correctly by comparing the simulation results with the experimental data.The experiment shows that the airflow speed has a great influence on the flow of the water.The submerged depth of the nozzle has a relatively smaller influence on the penetration depth and the surface fluctuation height in the liquid phase.When the nozzle is at a downward angle of 15°,the penetration depth and the surface fluctuation height are reduced.It is concluded that the numerical results with the realizable k-εturbulence model are the closest to the experiment for the penetration depth,the surface fluctuation height and the bubble scale. 展开更多
关键词 side-blown furnace hydraulic model numerical simulation turbulence model
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Validation of the numerical simulation of fluid flow in the continuous casting tundish 被引量:8
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作者 LifengZhang 《Journal of University of Science and Technology Beijing》 CSCD 2005年第2期116-122,共7页
The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of resid... The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of residuals and mesh size on the simulation accuracy are discussed. The current investigation concludes that the following condition should be satisfied to get accurate enough simulation results: (1) If the dimension of the domain is in the order of cubic meters, the average size of cells in the mesh system should be at least smaller than 30 mm; (2) The normalized non-scaled residual should be reached at least smaller than 10-4. 展开更多
关键词 VALIDATION fluid flow continuous casting tundish numerical simulation k-ε turbulence model
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Two Improvements on Numerical Simulation of 2-DOF Vortex-Induced Vibration with Low Mass Ratio 被引量:1
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作者 KANG Zhuang NI Wen-chi +1 位作者 ZHANG Xu SUN Li-ping 《China Ocean Engineering》 SCIE EI CSCD 2017年第6期764-772,共9页
Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vor... Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vortex-induced vibration with low mass ratio, the accuracy is not satisfactory, especially for the maximum amplitudes. In Jauvtis and Williamson's work, the maximum amplitude of the cylinder with low mass ratio m*=2.6 can reach as large as 1.5D to be called as the "super-upper branch", but from current literatures, few simulation results can achieve such value, even fail to capture the upper branch. Besides, it is found that the amplitude decays too fast in the lower branch with the RANS-based turbulence model. The reason is likely to be the defects of the turbulence model itself in the prediction of unsteady separated flows as well as the unreasonable setting of the numerical simulation parameters. Aiming at above issues, a modified turbulence model is proposed in this paper, and the effect of the acceleration of flow field on the response of vortex-induced vibration is studied based on OpenFOAM. By analyzing the responses of amplitude, phase and trajectory, frequency and vortex mode, it is proved that the vortex-induced vibration can be predicted accurately with the modified turbulence model under appropriate flow field acceleration. 展开更多
关键词 2-DOF vortex-induced vibration numerical simulation modified turbulence model ACCELERATION
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A NEW DEPTH-AVERAGED TWO-EQUATION (K-) TURBULENT CLOSURE MODEL AND ITS APPLICATION TO NUMERICAL SIMULATION FOR A RIVER 被引量:2
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作者 Yu Li-ren, Shanghai Institute of Electric Power, Shanghai, 200090, P.R. China 《Journal of Hydrodynamics》 SCIE EI CSCD 1991年第2期21-28,共8页
The paper mainly focuses on describing the modification made to a new depth-averaged two-equation turbulent closure model based on the revised κ-ω model recently. In the case of side discharged jets with tempera- t... The paper mainly focuses on describing the modification made to a new depth-averaged two-equation turbulent closure model based on the revised κ-ω model recently. In the case of side discharged jets with tempera- ture difference and transverse current, the new model has been investigated numerically in detail. As a practical example of application to use the new model, the side discharge of the cooling water from three outlets into a natu- ral river on one bank has been simulated, and the geomorphic variation under water has been treated suitably. Two depth-averaged models, and have been used, the later was the unique one up to the present. Emphasis is placed on the comparative research with different models under the same computational conditions. It has been verified that if the discharged flow rates are relatively small, when the pollutant plume in the near and transitional zons is predicted, the agreement with experimental and field data simulated by the model is better than by the model or other methods commonly used in engineering. 展开更多
关键词 turbulent CLOSURE model AND ITS APPLICATION TO numerical simulation FOR A RIVER A NEW DEPTH-AVERAGED TWO-EQUATION ITS
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NUMERICAL SIMULATION OF METHANE-AIR TURBULENT JET FLAME USING A NEW SECOND-ORDER MOMENT MODEL 被引量:4
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作者 陈兴隆 周力行 张健 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2000年第1期41-47,共7页
A new second-order moment model for turbulent combustion is applied in the simulation of methane-air turbulent jet flame. The predicted results are compared with the experimental results and with those predicted using... A new second-order moment model for turbulent combustion is applied in the simulation of methane-air turbulent jet flame. The predicted results are compared with the experimental results and with those predicted using the well-known EBU-Arrhenius model and the original second-order moment model. The comparison shows the advantage of the new model that it requires almost the same computational storage and time as that of the original second-order moment model, but its modeling results are in better agreement with experiments than those using other models. Hence, the new second-order moment model is promising in modeling turbulent combustion with NOx formation with finite reaction rate for engineering application. 展开更多
关键词 turbulent combustion second-order moment model numerical simulation
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Numerical simulation of flow around square cylinder using different low-Reynolds number turbulence models 被引量:3
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作者 张泠 周军莉 +2 位作者 陈晓春 兰丽 张楠 《Journal of Central South University of Technology》 EI 2008年第4期564-568,共5页
ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged u... ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged unsteady flow field.Meanwhile,drag and lift coefficients of the four different low-Reynolds number turbulence models were analyzed.The simulated results of YANG-SHIH model are close to the large eddy simulation results and experimental results,and they are significantly better than those of ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMR models.The modification of the generation of turbulence kinetic energy is the key factor to a successful simulation for YANG-SHIH model,while the correction of the turbulence near the wall has minor influence on the simulation results.For ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMA models satisfactory simulation results cannot be obtained due to lack of the modification of the generation of turbulence kinetic energy.With the joint force of wall function and the turbulence models with the adoption of corrected swirl stream,flow around a square cylinder can be fully simulated with less grids by the near-wall. 展开更多
关键词 low-Reynolds number turbulence model flow around square cylinder numerical simulation
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THREE-DIMENSIONAL TURBULENCE NUMERICAL SIMULATION OF A STEPPED SPILLWAY OVERFLOW 被引量:10
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作者 Chen Qun College of Hydraulic and Hydroelectric, Sichuan University, Chengdu 610065, ChinaDai Guang qing State Key Hydraulics Laboratory of High Speed Flows, Sichuan University, Chengdu 610065, ChinaZhu Fen qing Geotechnic Engineering Co., Second 《Journal of Hydrodynamics》 SCIE EI CSCD 2002年第3期70-75,共6页
In this paper, the k ε turbulence model is used to simulate the three dimensional turbulence flow over the stepped spillway at the Yubeishan reservoir. In order to solve the curved free water surface and to handl... In this paper, the k ε turbulence model is used to simulate the three dimensional turbulence flow over the stepped spillway at the Yubeishan reservoir. In order to solve the curved free water surface and to handle the complex boundary conditions, the fractional Volume Of Fluid (VOF) model that is applicable to the solution of the stratified two phase flow is introduced along with k ε turbulence model and the unstructured grid is used for the discretization of the irregular simulation domain. By these methods, the turbulence flow field of the stepped spillway is simulated successfully. The location of the free surface along the spillway, the magnitude and distribution of the velocity, the pressure on the step surface, the turbulence kinetic energy and turbulence dissipation rate are obtained by simulation. The changes and distributions of these characteristics along the width of the spillway are also obtained. The energy dissipation ratio of the stepped spillway is calculated according to the upstream and downstream water depth and velocities 展开更多
关键词 stepped spillway turbulence numerical simulation turbulence model VOF model
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THREE-DIMENSIONAL TURBULENCE NUMERICAL SIMULATION OF A STEPPED SPILLWAY OVERFLOW 被引量:4
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作者 CHENQun DAIGuang-qing +1 位作者 ZHUFen-qing YANGQing 《Journal of Hydrodynamics》 SCIE EI CSCD 2004年第1期74-79,共6页
In this paper, the k-ε two-equation turbulence model was used to simulatethe three-dimensional turbulent flow of the stepped spillway at the Yubeishan reservoir. In order tosolve the curved free water surface and to ... In this paper, the k-ε two-equation turbulence model was used to simulatethe three-dimensional turbulent flow of the stepped spillway at the Yubeishan reservoir. In order tosolve the curved free water surface and to handle the complex boundary conditions, the fractionalVolume Of Fluid (VOF) model that is applicable to the solution of the stratified two-phase flow wasintorduced to the k-ε turbulence model and the unstructured grid was used for the discretization ofthe irregular simulation domain. By these methods, the turbulent flow field of the stepped spillwaywas simulated successfully. The location of the free surface along the spillway, the magnitude anddistribution of the velocity, the pressure distribution on the step surface, the turbulence kineticenergy and turbulence dissipation rate were obtained by simulation. The changes and distributions ofthese characteristics along the width of the spillway were also obtained. The energy dissipationratio of the stepped spillway was calculated according to the upstream and downstream water depthand velocities. 展开更多
关键词 stepped spillway turbulence numerical simulation turbulence model VOFmodel
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NUMERICAL SIMULATION OF 3-D TURBULENT FLOWS OVER DREDGED TRENCHES
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作者 Han Guoqi Wang Deguan Xu Xieqing Department of Environmental Engineering, Hohai University, Nanjing 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1989年第4期313-322,共10页
A 3- D free surface flow in open channels based on the Reynolds equations with the k-ε turbulence closure model is presented in this paper. Insted of the 'rigid lid' approximation, the solution of the free su... A 3- D free surface flow in open channels based on the Reynolds equations with the k-ε turbulence closure model is presented in this paper. Insted of the 'rigid lid' approximation, the solution of the free surface equation is implemented in the velocity-pressure iterative procedure on the basis of the conventional SIMPLE method. This model was used to compute the flow in rectangular channels with trenches dredged across the bottom. The velocity, eddy viscosity coefficient, turbulent shear stress, turbulent kinetic energy and elevation of the free surface can be obtained. The computed results are in good agreement with previous experimental data. 展开更多
关键词 3- D surface water flow model dredged trenches k turbulence model numerical simulation.
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Numerical simulation of the flow within and over an intersection model with Reynolds-averaged Navier-Stokes method 被引量:8
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作者 李磊 胡非 +2 位作者 程雪玲 姜金华 马晓光 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第1期149-155,共7页
In this study, the Reynolds-averaged Navier-Stokes (RANS) method is employed to simulate the flow within and over an intersection model with three kinds of k-ε turbulence closure schemes, namely, standard model, re... In this study, the Reynolds-averaged Navier-Stokes (RANS) method is employed to simulate the flow within and over an intersection model with three kinds of k-ε turbulence closure schemes, namely, standard model, renormalization group (RNG) model and realizable k-ε model. The comparison between the simulated and observed flow fields shows that the RANS simulation with all the three turbulence models cannot completely and accurately reproduce the observed flow field in all details. A detailed comparison between the predicted profiles of wind velocities and the measured data shows that the realizble k-ε model is the best one among the three turbulence closure models in general. However, the extent to which the improvement is achieved by the realizable k-ε model is still not enough to completely and accurately describe the turbulent flow in a relatively complex environment. 展开更多
关键词 RANS numerical simulation INTERSECTION turbulence closure model
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THREE-DIMENSIONAL NUMERICAL SIMULATION OF AERATED FLOWS DOWNSTREAM SUDDEN FALL AERATOR EXPANSION-IN A TUNNEL 被引量:8
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作者 ZHANG Jian-min CHEN Jian-gang XU Wei-lin WANG Yu-rong LI Gui-ji 《Journal of Hydrodynamics》 SCIE EI CSCD 2011年第1期71-80,共10页
Air entrainment is known to be one of efficient and inexpensive methods to prevent cavitation damages in hydropower projects.The shape of sudden expansion-fall is used as a common device for mitigating cavitation eros... Air entrainment is known to be one of efficient and inexpensive methods to prevent cavitation damages in hydropower projects.The shape of sudden expansion-fall is used as a common device for mitigating cavitation erosions.The complex flow patterns with cavitation are numerically simulated by using the realizable k-εturbulence model and the air-water mixture model.The calculated results are compared well with the experimental results as well as those obtained with the k-εturbulence model with the Volume Of Fluid(VOF)Model.The calculated results agree well with the experimental data for the aeration cavity and wall pressure.Moreover,the air concentration near sidewall is simulated by a mixture model.It is found that the mixture turbulence model is superior to the VOF turbulence model. 展开更多
关键词 sudden expansion-fall aerator RNG k-εturbulence model realizable k-εturbulence model Volume Of Fluid (VOF)method air-water Mixture turbulence model numerical simulation
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Numerical Simulation and Analysis of Gas Flow Field in Serrated Valve Column 被引量:12
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作者 王良华 崔觉剑 姚克俭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第4期541-546,共6页
A three-dimensional computational fluid dynamics (CFD) model for gas flow through a serrated valve tray was presented. The flow field, as well as the dry-pressure drop of the valve under the full-opening condition w... A three-dimensional computational fluid dynamics (CFD) model for gas flow through a serrated valve tray was presented. The flow field, as well as the dry-pressure drop of the valve under the full-opening condition was simulated based on the proposed model by using FLUENT 6.0 software. Compared with the values of dry-pressure dro.p in different turbulent models, the.simulated.results using RNG κ-ε model are in reasonable agreement with experimental data, indicating that RNG κ-ε model is suitable in simulating gas flow through the serrated valve tray. Then the CFD model combining RNG κ-ε model was used to study the three-dimensional gas flow through the considered serrated valve tray. The simulated results showed that various eddies existed on the serrated valve tray, and both the eddy and the non-eddy areas were nearly equal. The existence of addendum can decrease the eddy area caused by gas passing through the lateral outlet slots. The size of eddies can be reduced by optimizing the distance between valves. 展开更多
关键词 serrated valve numerical simulation pressure drop RNG κ-ε turbulent model
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