检索结果-南通市图书馆

DNS of compressible turbulent boundary layer around a sharp cone

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2008年第6期51卷 699-714页

作者： li xinliang fu dexun ma yanwen State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100080China

Direct numerical simulation of the turbulent boundary layer over a sharp cone with 20° cone angle (or 10° half-cone angle) is performed by using the mixed seventh- order up-wind biased finite difference scheme and sixth-order central difference scheme. The free stream mach number is 0.7 and free stream unit Reynolds number is 250000/inch. The characteristics of transition and turbulence of the sharp cone boundary layer are compared with those of the flat plate boundary layer. Statistics of fully developed turbulent flow agree well with the experimental and theoretical data for the turbulent flat-plate boundary layer flow. The near wall streak-like structure is shown and the average space between streaks (normalized by the local wall unit) keeps approximately invariable at different streamwise locations. The turbulent energy equation in the cylindrical coordinate is given and turbulent en-ergy budget is studied. The computed results show that the effect of circumferen-tial curvature on turbulence characteristics is not obvious.

关键词： direct numerical simulation boundary layer transition sharp-cone turbulent kinetic energy budget

Optimization of the MUSCL scheme by dispersion and dissipation

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2012年第5期55卷 844-853页

作者： LENG Yan li xinliang fu dexun ma yanwen The State Key Laboratory of High-temperature Gas Dynamics(LHD) Institute of MechanicsChinese Academy of SciencesBeijing 100190China The State Key Laboratory of Nonlinear Mechanics(LNM) Institute of MechanicsChinese Academy of SciencesBeijing 100190China

A second-order optimized monotonicity-preserving MUSCL scheme(OMUSCL2) is developed based on the dispersion and dissipation optimization and monotonicity-preserving *** new scheme(OMUSCL2) is simple in expression and is easy for use in CFD *** with the original second-order or third-order MUSCL scheme,the new scheme shows nearly the same CPU cost and higher resolution to shockwaves and small-scale *** new scheme has been tested through a set of one-dimensional and two-dimensional tests,including the Shu-Osher problem,the Sod problem,the Lax problem,the two-dimensional double mach reflection and the RAE2822 transonic airfoil *** numerical tests show that,compared with the original MUSCL schemes,the new scheme causes fewer dispersion and dissipation errors and produces higher resolution.

关键词： MUSCL scheme monotonicity-preserving resolution dissipation/dispersion error optimization

Receptivity to free-stream disturbance waves for hypersonic flow over a blunt cone

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1682-1690页

作者： ZHANG YuDong fu dexun ma yanwen li xinliang China Academy of Aerospace Aerodynamics Beijing 100074China LNM Institute of MechanicsChinese Academy of SciencesBeijing 100190China

A high-order shock-fitting finite difference scheme is studied and used to do direc-tion numerical simulation (DNS) of hypersonic unsteady flow over a blunt cone with fast acoustic waves in the free stream, and the receptivity problem in the blunt cone hypersonic boundary layers is studied. The results show that the acoustic waves are the strongest disturbance in the blunt cone hypersonic boundary layers. The wave modes of disturbance in the blunt cone boundary layers are first, second, and third modes which are generated and propagated downstream along the wall. The results also show that as the frequency decreases, the amplitudes of wave modes of disturbance increase, but there is a critical value. When frequency is over the critial value, the amplitudes decrease. Because of the discontinuity of curvature along the blunt cone body, the maximum amplitudes as a function of frequencies are not monotone.

关键词： receptivity shock-fitting compact upwind scheme DNS blunt cone

A 5th order monotonicity-preserving upwind compact difference scheme

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第3期54卷 511-522页

作者： HE ZhiWei li xinliang fu dexun ma yanwen The Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China The State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

Based on an upwind compact difference scheme and the idea of monotonicity-preserving, a 5th order monotonicity-preserving upwind compact difference scheme （m-UCD5） is proposed. The new difference scheme not only retains the advantage of good resolution of high wave number but also avoids the Gibbs phenomenon of the original upwind compact difference scheme. Compared with the classical 5th order WENO difference scheme, the new difference scheme is simpler and small in diffusion and computation load. By employing the component-wise and characteristic-wise methods, two forms of the new difference scheme are proposed to solve the N-S/Euler equation. Through the Sod problem, the Shu-Osher problem and tbe two-dimensional Double mach Reflection problem, numerical solutions have demonstrated this new scheme does have a good resolution of high wave number and a robust ability of capturing shock waves, leading to a conclusion that the new difference scheme may be used to simulate complex flows containing shock waves.

关键词： upwind compact scheme monotonicity-preserving compressible flows shock capturing scheme

Complex Transition of Double-Diffusive Convection in a Rectangular Enclosure with Height-to-Length Ratio Equal to 4: Part I

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第7期6卷 247-268页

作者： Xian liang xinliang li dexun fu yanwen ma Shanghai Institute of Applied mathematics and Mechanics Shanghai UniversityNo.149 Yanchang RoadShanghai 200072China LNM Institute of MechanicsChinese Academy of SciencesNo.15 Beisihuanxi RoadBeijing 100190China

This is the first part of direct numerical simulation(DNS)of double-diffusive convection in a slim rectangular enclosure with horizontal temperature and concentration *** consider the case with the thermal Rayleigh number of 105,the Pradtle number of 1,the Lewis number of 2,the buoyancy ratio of composition to temperature being in the range of[0,1],and height-to-width aspect ration of 4.A new 7thorder upwind compact scheme was developed for approximation of convective terms,and a three-stage third-order Runge-Kutta method was employed for time *** DNS suggests that with the buoyancy ratio increasing form 0 to 1,the flow of transition is a complex series changing from the steady to periodic,chaotic,periodic,quasi-periodic,and finally back to *** are two types of periodic flow,one is simple periodic flow with single fundamental frequency(FF),and another is complex periodic flow with multiple *** process is illustrated by using time-velocity histories,Fourier frequency spectrum analysis and the phase-space trajectories.

关键词： Double diffusive convection transition periodic motion chaotic motion high order compact

DNS of compressible turbulent boundary layer over a blunt wedge

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2005年第2期48卷 129-141页

作者： li xinliang fu dexun ma Yanwan LNM Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China LNM Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China LNM Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Direct numerical simulation of spatially evolving compressible boundary layer over a blunt wedge is performed in this paper. The free-stream mach number is 6 and the disturbance source produced by wall blowing and suction is located downstream of the sound-speed point. Statistics are studied and compared with the results in incompressible flat-plate boundary layer. The mean pressure gradient effects on the vortex structure are studied.

关键词： boundary layer, transition, direct numerical simulation, compressible turbulence.

Difference schemes on non-uniform mesh and their application

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:materials International 2004年第10期14卷 8-14页

作者： ma yanwen ,GAO Hui,fu dexun and li xinliang (Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing100080,China) Chinese Acad Sci Inst Mech Lab Nonlinear Mech Beijing 100080 Peoples R China

High order accurate schemes are needed to simulate the multi-scale complex flow fields to get fine structures in simula-tion of the complex flows with large gradient of fluid parameters near the wall,and schemes on non-uniform mesh are desirable for many CFD(computational fluid dynamics)*** construction methods of difference approximations and several difference approxima-tions on non-uniform mesh are *** accuracy of the methods and the influence of stretch ratio of the neighbor mesh increment on accuracy are *** comments on these methods are given,and comparison of the accuracy of the results obtained by schemes based on both non-uniform mesh and coordinate transformation is made,and some numerical examples with non-uniform mesh are present-ed.

关键词： scheme on non-uniform mesh high order accurate scheme compact difference approximation

Direct numerical simulation of shock/turbulent boundary layer interaction in a supersonic compression ramp

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1651-1658页

作者： li xinliang1,fu dexun2,ma yanwen2 & liANG Xian1 1 Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China 2 The State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China 1. Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China2. The State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

A direct numerical simulation of the shock/turbulent boundary layer interaction flow in a supersonic 24-degree compression ramp is conducted with the free stream mach number *** blow-and-suction disturbance in the upstream wall boundary is used to trigger the *** the mean wall pressure and the velocity profiles agree with those of the experimental data,which validates the *** turbulent kinetic energy budget in the separation region is *** show that the turbulent production term increases fast in the separation region,while the turbulent dissipation term reaches its peak in the near-wall *** turbulent transport term contributes to the balance of the turbulent conduction and turbulent *** on the analysis of instantaneous pressure in the downstream region of the mean shock and that in the separation bubble,the authors suggest that the low frequency oscillation of the shock is not caused by the upstream turbulent disturbance,but rather the instability of separation bubble.

关键词： compression ramp shock/turbulent boundary layer interaction direct numerical simulation shock oscillation

在线全文

学校读者我要写书评

暂无评论

捕捉激波的群速度控制方法

空气动力学学报 2014年第5期32卷 575-580页

作者：李新亮傅德薰马延文中国科学院力学研究所高温气体动力学国家重点实验室北京100190

回顾及综述了群速度控制方法基本原理、发展过程及最新进展。群速度控制方法是通过控制色散误差以捕捉间断的一种数值方法。该方法通过在间断两侧采用不同色散类型的格式,将数值波的传播压制在间断附近,避免数值振荡向周围扩散,从而达... 详细信息

回顾及综述了群速度控制方法基本原理、发展过程及最新进展。群速度控制方法是通过控制色散误差以捕捉间断的一种数值方法。该方法通过在间断两侧采用不同色散类型的格式,将数值波的传播压制在间断附近,避免数值振荡向周围扩散,从而达到抑制数值振荡的效果。该方法主体上采用数值色散抑制振荡,实际使用中仅需补充较低水平的数值耗散就可将振荡压制在可接受的范围内。因而群速度控制格式的总体耗散水平较低,易于实现小尺度波的高分辨率捕捉,是复杂流动高分辨率数值模拟的有效方法。

关键词：群速度控制格式激波捕捉格式高分辨率色散耗散