Large Eddy Simulation Of Compressible Turbulent Channel Flow At Low Reynolds Number

Compressible turbulence is a great challenge and major topic in fluid dyna mics.With the rapid development of computational fluid dynamics technology,continuous increase of computing method and science, and the wide use oflarge-scale parallel computing techno logy, large-eddy simulation method is playingan increasingly important role in revealing the mechanism of complex flowphenomena.In this paper, the LES development history was initially analyzed. In addition,the present domestic and foreign researching situation, as well as the implicatedcharacteristics was obtained. According to the fundamental algorithm of large-eddysimulation method, compressible LES governing equations that can be applieduniversally on engineering practice were derived.Based on the existing LES solver, a new LES code was finished which wasused to solve the compressible turbulent questions. LES code possessed thefollowing features: the governing equations of the code are compressibleNavier-Stokes equations, at the same time two types of the subgrid stress (SGS)models are brought in the equations, which are Smagorinsky model and dynamicmodel. The finite volume method was used to discretize the equations, theconvective terms are fourth order centered schemes, viscous terms are second ordercentered scheme and time integration was third-order three-stage compactRunge-Kutta method. The code has a strong ability to the simulation of realphysical environment.It is maintained that fully developed turbulent channel flow was used tovalidate the new code. The basic principles and characteristics of turbulent channelflow were analyzed. The flowfield analysis was carried on. Mean properties,turbulence intensities, Reynolds shear stress statistics, higher-order statistics wereall consistent with the results of DNS. Test results indicate that this LEScomputation code has used relatively few grid points while the results arereasonably modified to obtain a better result, which is of importance for LEScomputation applied on the practical engineering purposes. A fully developedcompressible turbulent flow in a channel with an arc-shaped bump at a lower walland an upper-flat wall was numerically studied. Compressible turbulentcharacteristics for different altitudes of the arc-shaped bump and the dynamicbehavior of the near-wall turbulence were investigated. Near the bump, theturbulent kinetic energy budgets are significantly different from that of the channel.And the near wall turbulent struetures are also changed. The code is able to dealflow problems with complex geometry or physical boundary conditions, so it is suitable for the applications of complex flow phenomena.