# High speed flows

 Register Blogs Members List Search Today's Posts Mark Forums Read

 December 31, 2005, 03:37 High speed flows #1 Raj Guest   Posts: n/a Hi, Somebody help me to model the high speed (Mach >3) flow in CFD..i try to simulate the Missile FLume studies by cold flow approximation it is not at all converging..i heard that for high mach flows, Density based algorithms would work better than Pressure based algorithms ..it is true?..if it is, then FLUENT is having Density based alogithms? i also want to know Fluent is having ROE's Schem, Van Lear and kinietic based alogithms for solving high speed compressible flows like super sonic and hypersonic.. We tried the same probs in CFD-FASTRAN (Cold flow simulation) we got some good solution...the reason for that it is having DENSITY based alogithms and i have a option of selecting ROE or VANLEAR scheme, because i thing those scheme have robust to predict the shock in high speed regime compared to other scheme like relaxation etc.. ...but the same thing i am not able to get in FLUENT (that is ROE or VANLEAR Option)..i thing may be the algorithm in FLUENT is RELAXAION Based only ...] Thanks for ur help... Rajavel B

 January 1, 2006, 07:34 Re: High speed flows #2 veinan Guest   Posts: n/a In Fluent6.3 you can select FDS-ROE or AUSM

 January 9, 2006, 08:15 Re: High speed flows #3 Raj Guest   Posts: n/a Thanks veinen... but i thing this (FDS-ROE) is FDM based instead of FVM right...but i want FVM-ROE scheme... Rajavel

 January 9, 2006, 23:43 Re: High speed flows #4 S K Prasad Guest   Posts: n/a There is nothing like FVM Roe. Actually FVM is the way you discretize the governing equations to obtain a set of discrete equations for each control volume in the computational domain. Now in FVM, the rate of change of any quantity in a control volume is equal to flux crossing its boundaries. This flux consists of inviscid and viscous flux. To calculate the inviscid flux an array of schemes are available like Roe, AUSM, Van Leer, KFVS(kinetic scheme) to name a few. FDS stands for flux difference splitting and not finite difference scheme.

 January 10, 2006, 04:14 Re: High speed flows #5 raj Guest   Posts: n/a Thanks Prasad, I thought it is Finite DIfference Scheme...yes i also learned abt Flux Difference splitting,AUSM,Peculier velocity based Kinetic Scheme etc..in compressible flow alogrithms....i will try for my future modeling.... Thanks once again... Rajavel...