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Numerical investigation of cavity flow at subsonic and transonic speeds

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Journal of Beijing Institute of Technology 2014年第1期23卷 16-23页

作者：雷娟棉郑志伟周奇 School of Aerospace Engineering Beijing Institute of Technology

Based on finite volume method, subsonic and transonic flow in 3-D cavity of different length-to-depth ratios are numerically investigated by using Navier-Stokes equations with k-ε SST two-equation turbulence model and coupled implicit algorithm. The cavity streamline patterns and the static pressure coefficient distributions on the cavity floor are shown, and the flow characteristics of the cavity and the floor pressure coefficient distributions are analyzed. Numerical results demon- strate that the flow characteristics of the cavity at subsonic and transonic speeds are different from that of supersonic ones; length-to-depth ratio is the main factor that affects the flow characteristics of the cavity at subsonic and transonic number has a neglectable effect on the cavity floor pressure distributions. speeds and causes changes of the cavity flow type; Mach cavity flow fields at subsonic and transonic speeds and the

关键词： cavity flow numerical simulation length-to-depth ratio Mach number

EXPERIMENTAL STUDY OF HIGH SUBSONIC cavity flow OSCILLATION AND ITS SUPPRESSION BY ACOUSTIC EXCITATION

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Chinese Journal of Aeronautics 1998年第3期11卷 2-5页

作者：罗柏华胡章伟戴昌晖 School of Power and Energy Engineering Shanghai Jiao Tong UniversityShanghai 200030 China Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

An experimental study of cavity oscillating flow carried out on subsonic wall jet facilities in an anechoic room is summarized. The jet exit Mach number range is from 0.2 to 0.8. The effects of the flow Mach number ( Ma ) and the cavity depth ( D ) on the oscillation are studied. It is found that for L/D =4, (shallow cavity), the oscillation is mainly due to the self exciting of the free shear layer above the cavity opening, for L/D =2, the acoustic resonance is responsible for the oscillation. Preliminary tests are performed to study the suppression effect of the leading edge tone excitation on cavity flow, and considerable reduction of oscillation has been achieved when Ma ≤0.6.

关键词： cavity flow experimental aerodynamics acoustic excitation

Noise reduction in cavity flow by addition of porous media

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Acta Mechanica Sinica 2022年第2期38卷 68-80,I0003页

作者： Ruqian Guo Xiaopeng Chen Zhenhua Wan Haibao Hu Shuai Cui School of Mechanics Civil Engineering and ArchitectureNorthwestern Pnlytechnical UniversityXi'an 710129China School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China

Self-sustained oscillation and the sound radiation of flow over an open cavity is of great importance in nature and *** of filled porous media in the cavity are investigated numerically by using a lattice Boltzmann method in two-dimensional *** is shown that the outcomes of the porous patch depend on the location of the patch and the original flow mode,namely shear layer(SL)and wake mode(WM).For SL flow,the porous patch either damps the vortical flow or suppresses the generation of the secondary vortex sheet on the *** later effect destabilizes the ***,the radiated sound is reduced as the patch is on the trailing edge,and increased with porous patch on the floor,*** flow in WM,a transition from WM to SL mode is found when the porous patch is set either on the floor or behind the leading *** the cases,the recirculating flow on large scale is blocked significantly due to the porous patch,therefore,the WM flow is not *** the other hand,the porous patch on the trailing edge slightly weakens the sound due to *** study shows that assembling of porous media in the flow field decreases the radiated sound level only if it is done carefully.

关键词： cavity flow Lattice Boltzmann method Porous media Aeroacoustic Vortex

The Simulation of High Reynolds Number cavity flow Based on Fractional Volumetric Lattice Boltzmann Method

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Journal of Shanghai Jiaotong university(Science) 2005年第4期10卷 373-376页

作者： HAN Shan-ling（韩善灵） ZHU Ping（朱平） LIN Zhong-qin（林忠钦） School of Mechanical Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

The fractional volumetric lattice Boltzmann method with much better stability was used to simulate two-chmensional cavity flows. Because the effective viscosity was reduced by the fraction factor, it is very effective for simulating high Reynolds number flows. Simulations were carried out on a uniform grids system. The stream lines and the velocity profiles obtained from the simulations agree well with the standard lattice Boltzmann method simulations. Comparisons of detailed flow patterns with other studies via location of vortex centers are also satisfactory.

关键词： lattice Boltzmann method cavity flow fraction factor high Reynolds number flow

RESEARCH ON THE flow PROPERTY IN THREE DIMENSIONAL cavity OF MICRO-CHANNEL

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Journal of Hydrodynamics 2006年第1期18卷 20-25页

作者： BAO Fu-bing LIN Jian-zhong LIU Yan-hua Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China China Jiliang University Hangzhou 310018 China

The vortical property in a three dimensional cavity of micro-channel flow, which is very important, was investigated numerically. The results show that the rotation direction of vortex in the cavity depends on the dimension and shape of the cavity as well as the viscosity of the fluid. With the dimension and shape of the cavity fixed, there exists a critical inlet velocity. When the inlet velocity is less than the critical value, the rotation direction of vortex in the cavity will change. The critical velocity is directly proportional to the vis- cosity of the fluid, and inversely proportional to square of the thickness, length and depth of cavity. For the ratio of length and depth of cavity equals to one, there is a critical dimensionless parameter Recr , when Recr＇ is less than Recr＇ , the rotation direction of vortex will change too. Recr＇ is equal to 11.8 approximately.

关键词： micro channel cavity flow vortex numerical simulation

Effect of Bogie cavity End Wall Inclination on flow Field and Aerodynamic Noise in the Bogie Region of High-Speed Trains

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2175-2195页

作者： Jiawei Shi Jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically ***,the simulation is conducted based on a simplified cavity-bogie model,including five cases with different inclination angles of the front and rear walls of the *** comparing and analyzing the flow field and acoustic results of the five cases,the influence of the regularity and mechanism of the bogie cavity end wall inclination on the flow field and the aerodynamic noise of the bogie region are ***,the noise reduction strategy determined by the results of the simplified cavity-bogie model is applied to a three-car marshaling train model to verify its effectiveness when applied to the real *** results reveal that the forward inclination of the cavity front wall enlarges the influence area of shear vortex structures formed at the leading edge of the cavity and intensifies the interaction between the vortex structures and the front wheelset,frontmotor,and front gearbox,resulting in the increase of the aerodynamic noise generated by the bogie *** backward inclination of the cavity rear wall is conducive to guiding the vortex structures flow out of the cavity and weakening the interaction between the shear vortex structures and the cavity rear wall,leading to the reduction of the aerodynamic noise generated by the bogie *** the rear end wall of the foremost bogie cavity of the head car is a feasible aerodynamic noise reduction measure for high-speed trains.

关键词： Bogie cavity flow aerodynamic noise end wall inclination

Reynolds number dependence of flow past a shallow open cavity

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Science China(Technological Sciences) 2014年第11期57卷 2161-2171页

作者： CHEN Huai ZHONG Qiang WANG XingKui LI DanXun State Key Laboratory of Hydroscience and Engineering Tsinghua University

Measurements were carried out in a shallow open cavity with particle image velocimetry *** cavity has a lengthto-depth ratio of 4:1,and the upstream inflow conditions include laminar,transient,and turbulent regimes at seven different Reynolds *** measured instantaneous velocities were analyzed through ensemble average,vortex extraction,and proper orthogonal decomposition(POD)to investigate overall flow circulations,Reynolds stress distribution,spanwise vortex population,and the characteristics of the POD *** results reveal distinctive Reynolds number dependence of the cavity flow,*** increase in Reynolds number results in constant migration of the overall circulation,enhancement of Reynolds stress,reduction of correlation between vortex and Reynolds stress,and decrease of fractional energy of the characteristic POD ***,a phenomenological model was proposed to describe various features of cavity flow.

关键词： cavity flow Reynolds number Reynolds stress spanwise vortex particle image velocimetry

SIMULATION OF SEDIMENT DEPOSITION IN A cavity WITH FREE SURFACE

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Journal of Hydrodynamics 2010年第5期22卷 626-633页

作者： ZHANG Xiao-feng CUI Zhan-feng LU Xin-hua State Key Laboratory of Water Resource and Hydropower Engineering Science Wuhan University Wuhan 430072 China Yangtze River Scientific Research Institute Wuhan 430010 China

Studies of the flow and sediment movement in a cavity with free surface were mostly limited to physical modeling experiments. In this study, the sediment movement is characterized in detail using a 3-D turbulent numerical model. To close the Reynolds equations, the standard k-ε model is employed. The VOF method is adopted to capture the time varying free surface and the porosity method is introduced to deal with the irregular boundary and the varying bed deformation. The computation results agree well with the experimental data in major aspects such as the vertical distribution of the sediment concentration and the deposition topography in the cavity. The comparisons show that this model can well predict the flow structure and the sediment movement and also the river bed deformation in a cavity.

关键词： 3-D turbulent flow cavity flow free surface VOF porosity sediment transport

Coiflet Wavelet-Homotopy Solutions to Bio-Thermal Convection in a Square cavity

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Advances in Applied Mathematics and Mechanics 2023年第3期15卷 684-718页

作者： Sohail Ahmed Hang Xu Qiang Sun State Key Lab of Ocean Engineering School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Australian Research Council Centre of Excellence for Nanoscale BioPhotonics School of ScienceRMIT UniversityMelbourneVIC 3001Australia

In this paper,the natural convection of a complex fluid that contains both nanoparticles and gyrotactic microorganisms in a heated square cavity is *** Buongiorno model is applied to descirbe the nanofluid *** the top and bottom horizontal walls of the cavity are adiabatic,and there is a temperature difference between the left and right vertical *** non-dimensional governing equations are obtained when the stream-vorticity formulation of function is used,which are solved by the recently developed robust Coiflet wavelet homotopy analysis method.A rigid verification for the solver is ***,the effects of various physics parameters including the Rayleigh number,the buoyancy ratio parameter,the bioconvection Rayleigh number,the Prandtl number,the Brownian motion parameter,the thermophoresis parameter,the heat generation parameter,the Lewis number,the bioconvection Peclet number and the Schmidt number on this complicated natural convection are *** is known that natural convection is closely related to our daily life owing to its wide existence in nature and engineering *** believe that our work will make a significant contribution to a better understanding of the natural convection of a complex fluid in a cavity with suspensions of both inorganic nanoparticles and organic microorganisms.

关键词： cavity flow natural convection bio-thermal convection Coiflet wavelet homotopy analysis method