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Simulating high Reynolds number flow in two-dimensional lid-driven cavity by multi-relaxation-time lattice Boltzmann method 被引量:4
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作者 柴振华 施保昌 郑林 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第8期1855-1863,共9页
By coupling the non-equilibrium extrapolation scheme for boundary condition with the multi-relaxation-time lattice Boltzmann method, this paper finds that the stability of the multi-relaxation-time model can be improv... By coupling the non-equilibrium extrapolation scheme for boundary condition with the multi-relaxation-time lattice Boltzmann method, this paper finds that the stability of the multi-relaxation-time model can be improved greatly, especially on simulating high Reynolds number (Re) flow. As a discovery, the super-stability analysed by Lallemand and Luo is verified and the complex structure of the cavity flow is also exhibited in our numerical simulation when Re is high enough. To the best knowledge of the authors, the maximum of Re which has been investigated by direct numerical simulation is only around 50 000 in the literature; however, this paper can readily extend the maximum to 1000 000 with the above combination. 展开更多
关键词 multi-relaxation-time lattice Boltzmann method non-equilibrium extrapolation scheme high Reynolds number lid-driven cavity flow
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Transition to chaos in lid-driven square cavity flow 被引量:1
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作者 Tao Wang Tiegang Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第12期291-300,共10页
To date,there are very few studies on the transition beyond second Hopf bifurcation in a lid-driven square cavity,due to the difficulties in theoretical analysis and numerical simulations.In this paper,we study the ch... To date,there are very few studies on the transition beyond second Hopf bifurcation in a lid-driven square cavity,due to the difficulties in theoretical analysis and numerical simulations.In this paper,we study the characteristics of the third Hopf bifurcation in a driven square cavity by applying a consistent fourth-order compact finite difference scheme rectently developed by us.We numerically identify the critical Reynolds number of the third Hopf bifurcation located in the interval of(13944.7021,13946.5333)by the method of bisection.Through Fourier analysis,it is discovered that the flow becomes chaotic with a characteristic of period-doubling bifurcation when the Reynolds number is beyond the third bifurcation critical interval.Nonlinear time series analysis further ascertains the flow chaotic behaviors via the phase diagram,Kolmogorov entropy and maximal Lyapunov exponent.The phase diagram changes interestingly from a closed curve with self-intersection to an unclosed curve and the attractor eventually becomes strange when the flow becomes chaotic. 展开更多
关键词 unsteady lid-driven square cavity flows chaos time series analysis third Hopf bifurcation
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SUPG finite element method based on penalty function for lid-driven cavity flow up to Re = 27500 被引量:1
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作者 Da-Guo Wang Qing-Xiang Shui 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第1期54-63,共10页
A streamline upwind/Petrov-Galerkin (SUPG) finite element method based on a penalty function is pro- posed for steady incompressible Navier-Stokes equations. The SUPG stabilization technique is employed for the for-... A streamline upwind/Petrov-Galerkin (SUPG) finite element method based on a penalty function is pro- posed for steady incompressible Navier-Stokes equations. The SUPG stabilization technique is employed for the for- mulation of momentum equations. Using the penalty function method, the continuity equation is simplified and the pres- sure of the momentum equations is eliminated. The lid-driven cavity flow problem is solved using the present model. It is shown that steady flow simulations are computable up to Re = 27500, and the present results agree well with previous solutions. Tabulated results for the properties of the primary vortex are also provided for benchmarking purposes. 展开更多
关键词 Streamline upwind/Petrov-Galerkin (SUPG)finite element method lid-driven cavity flow Penaltyfunction method High Reynolds number
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The second Hopf bifurcation in lid-driven square cavity 被引量:1
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作者 Tao Wang Tiegang Liu Zheng Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期119-125,共7页
To date, there are very few studies on the second Hopf bifurcation in a driven square cavity, although there are intensive investigations focused on the first Hopf bifurcation in literature, due to the difficulties of... To date, there are very few studies on the second Hopf bifurcation in a driven square cavity, although there are intensive investigations focused on the first Hopf bifurcation in literature, due to the difficulties of theoretical analyses and numerical simulations. In this paper, we study the characteristics of the second Hopf bifurcation in a driven square cavity by applying a consistent fourth-order compact finite difference scheme recently developed by us. We numerically identify the critical Reynolds number of the second Hopf bifurcation located in the interval of(11093.75, 11094.3604) by bisection. In addition, we find that there are two dominant frequencies in its spectral diagram when the flow is in the status of the second Hopf bifurcation, while only one dominant frequency is identified if the flow is in the first Hopf bifurcation via the Fourier analysis. More interestingly, the flow phase portrait of velocity components is found to make transition from a regular elliptical closed form for the first Hopf bifurcation to a non-elliptical closed form with self-intersection for the second Hopf bifurcation. Such characteristics disclose flow in a quasi-periodic state when the second Hopf bifurcation occurs. 展开更多
关键词 unsteady lid-driven cavity flows SECOND HOPF bifurcation critical REYNOLDS number numerical simulation
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Coupling of discrete-element method and smoothed particle hydrodynamics for liquid-solid flows 被引量:2
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作者 Yrj Jun Huang Ole Jφrgen Nydal 《Theoretical & Applied Mechanics Letters》 CAS 2012年第1期55-58,共4页
Particle based methods can be used for both the simulations of solid and fluid phases in multiphase medium, such as the discrete-element method for solid phase and the smoothed particle hydrodynamics for fluid phase. ... Particle based methods can be used for both the simulations of solid and fluid phases in multiphase medium, such as the discrete-element method for solid phase and the smoothed particle hydrodynamics for fluid phase. This paper presents a computational method combining these two methods for solid-liquid medium. The two phases are coupled by using an improved model from a reported Lagrangian-Eulerian method. The technique is verified by simulating liquid-solid flows in a two-dimensional lid-driven cavity. 展开更多
关键词 discrete-element method smoothed particle hydrodynamics liquid-solid flows lid-driven cavity
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Unsteady Cavitation Analysis Using Phase Averaging and Conditional Approaches in a 2D Venturi Flow 被引量:2
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作者 Vincent Aeschlimann Stéphane Barre Henda Djeridi 《Open Journal of Fluid Dynamics》 2013年第3期171-183,共13页
The present study refers to a cavitating Venturi type section geometry characterized by a convergent angle of 18°?and a divergent angle of about 8°?where the sheet cavity presents typical self-oscillation be... The present study refers to a cavitating Venturi type section geometry characterized by a convergent angle of 18°?and a divergent angle of about 8°?where the sheet cavity presents typical self-oscillation behavior with quasi-periodic vapor clouds shedding. This work is an extension of previous works concerning void ratio measurements and velocity fields using double optical probe and constitutes a complete analysis of the two-phase structure of unsteady cavitating flow. This paper provides a new method based on conditional and phase averaging technique with wall pressure signal to treat experimental data in order to evaluate more precisely time-averaged and rms values of the void ratio and instantaneous velocity fields. Conditional analysis shows a different behavior of the two-phase flow dynamics leading to highlight high void ratio events linked to the break-off cycle. Unsteady phase averaging of the optical probe signal gives the evolution of the void ratio at each studied location in the venturi and shows that the fluctuations close to the wall (where the re-entrant jet is predominant) are in phase with the upper part of the cavity instead of the thickness of the cavity which is unchanged. 展开更多
关键词 unsteady CAVITATION Sheet cavity Optical Probes Venturi-Type flow TURBO Pump
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Mixed Convection Heat Transfer for Nanofluids in a Lid-Driven Shallow Rectangular Cavity Uniformly Heated and Cooled from the Vertical Sides:The Opposing Case
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作者 Hassan El Harfi Mohamed Naimi +2 位作者 Mohamed Lamsaadi Abdelghani Raji Mohammed Hasnaoui 《Journal of Electronics Cooling and Thermal Control》 2013年第3期111-130,共20页
An investigation on flow and heat transfer due to mixed convection, in a lid-driven rectangular cavity filled with Cu- water nanofluids and submitted to uniform heat flux along with its vertical short sides, has been ... An investigation on flow and heat transfer due to mixed convection, in a lid-driven rectangular cavity filled with Cu- water nanofluids and submitted to uniform heat flux along with its vertical short sides, has been conducted numerically by solving the full governing equations with the finite volume method and the SIMPLER algorithm. In the case of a slender enclosure, these equations are considerably reduced by using the parallel flow concept. Solutions, for the flow and temperature fields, and the heat transfer rate, have been obtained depending on the governing parameters, which are the Reynolds, the Richardson numbers and the solid volume fraction of nanoparticles. A perfect agreement has been found between the results of the two approaches for a wide range of the abovementioned parameters. It has been shown that at low and high Richardson numbers, the convection is ensured by lid and buoyancy-driven effects, respectively, whereas between these extremes, both mechanisms compete. Moreover, the addition of Cu-nanoparticles, into the pure water, has been seen enhancing and degrading heat transfer by lid and buoyancy-driven effects, respectively. 展开更多
关键词 Component Nanofluids Mixed Convection Heat Transfer lid-driven cavity Parallel flow Assumption Finite Volume Method
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Experimental and computational investigation on flow characteristics of rotating cavities with high inlet pre-swirl axial throughflow 被引量:1
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作者 Sipeng WANG Xiang LUO +4 位作者 Linji GUO Zeyu WU Yang BAI Zongchao LI Lichun MA 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第4期276-293,共18页
As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and u... As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and unstable flow field.The flow characteristics in an engine-like rotating multi-stage cavity with throughflow were investigated using particle image velocimetry,flow visualization technology and three-dimensional unsteady Reynolds-Averaged Navier-Stokes (RANS)simulations.The focus of current research was to understand the distribution of the mean swirl ratio and its variation with a wide range of non-dimensional parameters in the co-rotating cavity with high inlet pre-swirl axial throughflow.The maximum axial Reynolds number and rotational Reynolds numbers could reach 4.41×10^(4)and 1.24×10^(6),respectively.The velocity measurement results indicate that the mean swirl ratio is greater than 1 and decreases with an increase in the radial position.The flow structure is dominated by the Rossby number,and two different flow patterns (flow penetration and flow stratification) are identified and confirmed by flow visualization images.In the absence of buoyancy,the flow penetration caused by the precession of the throughflow makes it easier for the throughflow to reach a high radius region.Satisfactory consistency of results between measurements and numerical calculations is obtained.This study provides a theoretical basis and data support for toroidal vortex breakdown,which is of practical significance for the design of high-pressure compressor cavities. 展开更多
关键词 Compressor Axial throughflow Rotating cavity flow Particle image velocimetry unsteady RANS flow pattern
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Experimental Investigation on Cavitating Flow Shedding over an Axisymmetric Blunt Body 被引量:6
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作者 HU Changli WANG Guoyu HUANG Biao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第2期387-393,共7页
Nowadays,most researchers focus on the cavity shedding mechanisms of unsteady cavitating flows over different objects,such as 2D/3D hydrofoils,venturi-type section,axisymmetric bodies with different headforms,and so o... Nowadays,most researchers focus on the cavity shedding mechanisms of unsteady cavitating flows over different objects,such as 2D/3D hydrofoils,venturi-type section,axisymmetric bodies with different headforms,and so on.But few of them pay attention to the differences of cavity shedding modality under different cavitation numbers in unsteady cavitating flows over the same object.In the present study,two kinds of shedding patterns are investigated experimentally.A high speed camera system is used to observe the cavitating flows over an axisymmetric blunt body and the velocity fields are measured by a particle image velocimetry(PIV)technique in a water tunnel for different cavitation conditions.The U-type cavitating vortex shedding is observed in unsteady cavitating flows.When the cavitation number is 0.7,there is a large scale cavity rolling up and shedding,which cause the instability and dramatic fluctuation of the flows,while at cavitation number of 0.6,the detached cavities can be conjunct with the attached part to induce the break-off behavior again at the tail of the attached cavity,as a result,the final shedding is in the form of small scale cavity and keeps a relatively steady flow field.It is also found that the interaction between the re-entrant flow and the attached cavity plays an important role in the unsteady cavity shedding modality.When the attached cavity scale is insufficient to overcome the re-entrant flow,it deserves the large cavity rolling up and shedding just as that at cavitation number of 0.7.Otherwise,the re-entrant flow is defeated by large enough cavity to induce the cavity-combined process and small scale cavity vortexes shedding just as that of the cavitation number of0.6.This research shows the details of two different cavity shedding modalities which is worthful and meaningful for the further study of unsteady cavitation. 展开更多
关键词 cavity shedding unsteady cavitating flows high-speed video camera PIV re-entrant flow
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Numerical research on lid-driven cavity flows using a three-dimensional lattice Boltzmann model on non-uniform meshes 被引量:1
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作者 TANG XueLin SU YanWen +1 位作者 WANG FuJun LI LinWei 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第9期2178-2187,共10页
A lattice Boltzmann model combined with curvilinear coordinate is proposed for lid-driven cavity three-dimensional (3D) flows. For particle velocity distribution, the particle collision process is performed in physica... A lattice Boltzmann model combined with curvilinear coordinate is proposed for lid-driven cavity three-dimensional (3D) flows. For particle velocity distribution, the particle collision process is performed in physical domain, and the particle streaming process is carried out in the corresponding computational domain, which is transferred from the physical domain using interpolation method. For the interpolation calculation, a second-order upwind interpolation method is adopted on internal lattice nodes in flow fields while a second-order central interpolation algorithm is employed at neighbor-boundary lattice nodes. Then the above-mentioned model and algorithms are used to numerically simulate the 3D flows in the lid-driven cavity at Reynolds numbers of 100, 400 and 1000 on non-uniform meshes. Various vortices on the x-y, y-z and x-z symmetrical planes are successfully predicted, and their changes in position with the Reynolds number increasing are obtained. The velocity profiles of u component along the vertical centerline and w component along the horizontal centerline are both in good agreement with the data in literature and the calculated results on uniform meshes. Besides, the velocity vector distributions on various cross sections in lid-driven cavity predicted on non-uniform meshes are compared with those simulated on uniform meshes and those in the literature. All the comparisons and validations show that the 3D lattice Boltzmann model and all the numerical algorithms on non-uniform meshes are accurate and reliable to predict effectively flow fields. 展开更多
关键词 lattice Boltzmann model interpolation algorithms body-fitted meshes lid-driven cavity flows
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Chaotic Lid-Driven Square Cavity Flows at Extreme Reynolds Numbers 被引量:1
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作者 Salvador Garcia 《Communications in Computational Physics》 SCIE 2014年第3期596-617,共22页
This paper investigates the chaotic lid-driven square cavity flows at extreme Reynolds numbers.Several observations have been made from this study.Firstly,at extreme Reynolds numbers two principles add at the genesis ... This paper investigates the chaotic lid-driven square cavity flows at extreme Reynolds numbers.Several observations have been made from this study.Firstly,at extreme Reynolds numbers two principles add at the genesis of tiny,loose counterclockwise-or clockwise-rotating eddies.One concerns the arousing of them owing to the influence of the clockwise-or counterclockwise currents nearby;the other,the arousing of counterclockwise-rotating eddies near attached to the moving(lid)top wall which moves from left to right.Secondly,unexpectedly,the kinetic energy soon reaches the qualitative temporal limit’s pace,fluctuating briskly,randomly inside the total kinetic energy range,fluctuations which concentrate on two distinct fragments:one on its upper side,the upper fragment,the other on its lower side,the lower fragment,switching briskly,randomly from each other;and further on many small fragments arousing randomly within both,switching briskly,randomly from one another.As the Reynolds number Re→∞,both distance and then close,and the kinetic energy fluctuates shorter and shorter at the upper fragment and longer and longer at the lower fragment,displaying tall high spikes which enlarge and then disappear.As the time t→∞(at the Reynolds number Re fixed)they recur from time to time with roughly the same amplitude.For the most part,at the upper fragment the leading eddy rotates clockwise,and at the lower fragment,in stark contrast,it rotates counterclockwise.At Re=109 the leading eddy-at its qualitative temporal limit’s pace—appears to rotate solely counterclockwise. 展开更多
关键词 Navier-Stokes equations lid-driven square cavity flows chaos
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Least Square Finite Element Method for Viscous Splitting of Unsteady Incompressible Navier–Stokes Equations
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作者 SHUI Qing-xiang WANG Da-guo +1 位作者 HE Zhi-liang HUANG Jin 《China Ocean Engineering》 SCIE EI CSCD 2018年第4期490-500,共11页
In order to solve unsteady incompressible Navier–Stokes(N–S) equations, a new stabilized finite element method,called the viscous-splitting least square FEM, is proposed. In the model, the N–S equations are split i... In order to solve unsteady incompressible Navier–Stokes(N–S) equations, a new stabilized finite element method,called the viscous-splitting least square FEM, is proposed. In the model, the N–S equations are split into diffusive and convective parts in each time step. The diffusive part is discretized by the backward difference method in time and discretized by the standard Galerkin method in space. The convective part is a first-order nonlinear equation.After the linearization of the nonlinear part by Newton’s method, the convective part is also discretized by the backward difference method in time and discretized by least square scheme in space. C0-type element can be used for interpolation of the velocity and pressure in the present model. Driven cavity flow and flow past a circular cylinder are conducted to validate the present model. Numerical results agree with previous numerical results, and the model has high accuracy and can be used to simulate problems with complex geometry. 展开更多
关键词 unsteady incompressible N–S equations viscous splitting Newton's method least square finite element method driven cavity flow flow past a circular cylinder
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旋成体射弹倾斜入水运动仿真 被引量:3
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作者 赵旭 胡欣康 姚蕊 《国防科技大学学报》 EI CAS CSCD 北大核心 2023年第4期115-123,共9页
为了研究运动参数和弹头外形对弹体斜入水过程的影响规律,采用气液两相流体积分数和水汽空化模型,通过嵌套网格实现刚体三自由度运动学和动力学耦合,模拟了弹体以80~100 m/s速度倾斜入水开空泡阶段的运动过程。经文献实验验证,入水弹体... 为了研究运动参数和弹头外形对弹体斜入水过程的影响规律,采用气液两相流体积分数和水汽空化模型,通过嵌套网格实现刚体三自由度运动学和动力学耦合,模拟了弹体以80~100 m/s速度倾斜入水开空泡阶段的运动过程。经文献实验验证,入水弹体速度与位移的误差为0~6%和-8%~0,转动角度误差为-6%~0。通过对入水速度和入水角度的多工况模拟研究,发现入水速度增大,弹体轴向冲击载荷增大,最大载荷与速度的平方呈线性关系,弹体速度非线性衰减率大;入水角增大,弹体转动角速率减小,运动稳定性强,速度衰减率不受入水角影响。与圆锥头部弹体相比,采用头部阶梯状修型后的弹体的平均速度衰减率、转动角速率和最大轴向冲击载荷分别降低到66.7%、40%和77.2%,显著提高了运动稳定性。 展开更多
关键词 入水弹道 入水空泡 运动方程 CFD 非定常流动
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NUMERICAL SIMULATIONS OF 2D PERIODIC UNSTEADY CAVITATING FLOWS 被引量:11
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作者 WU Lei LU Chuan-jing LI Jie CHEN Xin 《Journal of Hydrodynamics》 SCIE EI CSCD 2006年第3期341-344,共4页
A two-phase mixture model was established to study unsteady cavitating flows. A local compressible system of equations was derived by introducing a density-pressure function to account for the two-phase flow of water/... A two-phase mixture model was established to study unsteady cavitating flows. A local compressible system of equations was derived by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for solving the variable-density Navier-Stokes equations of cavitating flow problem was put forward. The numerical results for unsteady characteristics of cavitating flows on a 2D NACA hydrofoil coincide well with experimental data. 展开更多
关键词 unsteady cavitating flow variable-density Navier-Stokes equations periodic cavity break-off and shedding HYDROFOIL
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Experimental study of unsteady supersonic flow interacting with porous cavity and jets or rods
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作者 Nao Kuniyoshi Minoru Yaga +1 位作者 Isao Teruya Masaaki Ishikawa 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第2期153-159,共7页
In this study,an experiment was performed to clarify the flow field,in which the jets were normally injected into a main supersonic flow surrounded by a porous cavity,and this report figures out interaction between st... In this study,an experiment was performed to clarify the flow field,in which the jets were normally injected into a main supersonic flow surrounded by a porous cavity,and this report figures out interaction between starting shock wave and porous cavity.In the experiment,a porous cavity is attached to a main duct and jets and rods are inserted to the main duct on the porous cavity.To reveal this flow field,the thermal tuft probe was adopted to experimentally investigate the flow in the cavity.In the experiments,the effect of the porous cavity with jets or rods on the flow field is studied by means of visualization of schlieren method with a high speed camera and measurement of cavity flow with thermal tuft probe.As a results,frequency analysis of output of the thermal tuft probe revealed that some clear dominant frequencies were confirmed when the starting shock wave existed around the porous cavity in all cases of jets and rods arrangements.Moreover,visualization of schlieren method with a high speed camera clarified that a starting shock wave had the same dominant frequencies as that of the flow fluctuation in the cavity only around the cavity. 展开更多
关键词 Shock wave Compressible flow Porous cavity unsteady flow direction
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Supersonic Cavity Flows over Concave and Convex Walls
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作者 A Ran Ye Rajarshi Das +1 位作者 Toshiaki Setoguchi Heuy Dong Kim 《Journal of Thermal Science》 SCIE EI CAS CSCD 2016年第2期145-152,共8页
Supersonic cavity flows are characterized by compression and expansion waves, shear layer, and oscillations inside the cavity. For decades, investigations into cavity flows have been conducted, mostly with flows at ze... Supersonic cavity flows are characterized by compression and expansion waves, shear layer, and oscillations inside the cavity. For decades, investigations into cavity flows have been conducted, mostly with flows at zero pressure gradient entering the cavity in straight walls. Since cavity flows on curved walls exert centrifugal force, the features of these flows are likely to differ from those of straight wall flows. The aim of the present work is to study the flow physics of a cavity that is cut out on a curved wall. Steady and unsteady numerical simulations were carried out for supersonic flow through curved channels over the cavity with L/H = 1. A straight channel flow was also analyzed which serves as the base model. The velocity gradient along the width of the channel was observed to increase with increasing the channel curvature for both concave and convex channels. The pressure on the cavity floor increases with the increase in channel curvature for concave channels and decreases for convex channels. Moreover, unsteady flow characteristics are more dependent on channel curvature under supersonic free stream conditions. 展开更多
关键词 cavity flow Supersonic flow Compressible flow unsteady flow Pressure Oscillation
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非定常空泡闭合区域最大压力的理论研究 被引量:6
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作者 陈玮琪 王宝寿 +2 位作者 易淑群 郑俊 褚学森 《力学学报》 EI CSCD 北大核心 2012年第4期701-708,共8页
当物体在流体中高速运动产生空泡时,空泡通常以回射流的形式闭合在物体表面上,并在闭合位置对物体表面产生流体超压.在物体表面上的空泡闭合位置一般不是固定的,其位置根据物体运动速度的变化、空泡压力的变化及重力场中的位置等因素而... 当物体在流体中高速运动产生空泡时,空泡通常以回射流的形式闭合在物体表面上,并在闭合位置对物体表面产生流体超压.在物体表面上的空泡闭合位置一般不是固定的,其位置根据物体运动速度的变化、空泡压力的变化及重力场中的位置等因素而在物体表面发生快速移动,在非对称情况下,这种移动超压会极大影响运动物体的稳定性.基于势流理论研究了重力场中非定常垂直空泡闭合区域中最大压力的存在位置,推导了最大压力的理论公式,揭示了最大压力与空泡发展速度之间的关系,证明了最大压力点的两个特殊流体性质.最后设计了测量空泡闭合区域最大压力的验证性试验,并将理论计算结果与试验测量结果进行了对比,验证了理论研究结果. 展开更多
关键词 空泡 回射流 尾流压力 非定常空泡流
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航行器垂直入水空泡特性与流体动力研究 被引量:11
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作者 胡平超 张宇文 袁绪龙 《计算机仿真》 CSCD 北大核心 2011年第6期5-8,共4页
研究超空泡航行器垂直入水空泡形态与流体动力特性,针对空泡出现流体动力特性改变,为了确定入水参数,根据标准k-ε模型,采用三维动网格技术,对超空泡航行器入水过程重力场下非定常空泡特性以及流体动力参数进行了数值仿真。得出结果,攻... 研究超空泡航行器垂直入水空泡形态与流体动力特性,针对空泡出现流体动力特性改变,为了确定入水参数,根据标准k-ε模型,采用三维动网格技术,对超空泡航行器入水过程重力场下非定常空泡特性以及流体动力参数进行了数值仿真。得出结果,攻角越大,空泡形态不对称性越明显,迎流面空泡越短越薄,背流面空泡越长越厚,迎流面与背流面的空泡闭合时差越大,且流体动力系数越大。证明对同一入水深度时,从曲线上分析,阻力系数的斜率基本一致,升力系数与俯仰力矩系数的斜率随攻角的增大而增大。研究结果可为入水弹道的研究提供了流体动力参数。 展开更多
关键词 空泡形态 流体动力 非定常 数值仿真 动网格
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轴向通流旋转盘腔中流动与传热数值研究 被引量:4
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作者 谭勤学 任静 蒋洪德 《工程热物理学报》 EI CAS CSCD 北大核心 2009年第7期1129-1131,共3页
本文采用三维N-S非定常计算方法对旋转盘腔中的流动与传热进行了数值研究。数值计算结果表明:下游盘的Nu数径向分布与实验结果吻合较好,上游盘趋势吻合但数值上有一定差别;旋转盘腔中流体的整体转动速度小于旋转圆盘的转动速度。进一步... 本文采用三维N-S非定常计算方法对旋转盘腔中的流动与传热进行了数值研究。数值计算结果表明:下游盘的Nu数径向分布与实验结果吻合较好,上游盘趋势吻合但数值上有一定差别;旋转盘腔中流体的整体转动速度小于旋转圆盘的转动速度。进一步计算结果表明,重力的影响大小与整体流态转速相对坐标系转速的比值密切相关,该相对转速越大影响越小,反之越大。 展开更多
关键词 旋转盘腔 浮升力 非定常流 轴向通流
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基于时间的驱动方腔流的高精度多重网格方法数值模拟 被引量:5
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作者 葛永斌 田振夫 吴文权 《工程热物理学报》 EI CAS CSCD 北大核心 2003年第2期216-219,共4页
提出了一种求解二维非定常不可压缩Navier-Stokes方程组的全隐二阶时间推进和空间四阶差分紧致格式,在每一个时间步上,采用多重网格的全近似格式(FAS)加速其迭代收敛过程。利用该方法对驱动方腔流动问题进行了直接数值模拟,结果显示对... 提出了一种求解二维非定常不可压缩Navier-Stokes方程组的全隐二阶时间推进和空间四阶差分紧致格式,在每一个时间步上,采用多重网格的全近似格式(FAS)加速其迭代收敛过程。利用该方法对驱动方腔流动问题进行了直接数值模拟,结果显示对于Re≤5000,本文在粗网格上(64×64等分和128×128等分)即可得到较为准确的定常层流解;对于Re=7500和10000,由于更多二次涡的出现,本文在256×256等分网格上同样可得到与前人的结果相吻合的非定常周期性解。 展开更多
关键词 数值模拟 驱动方腔流 非定常Navier-Stokes方程 高精度紧致格式 多重网格 不可压缩粘性流动 非定常周期解
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