|
[Sponsors] |
February 18, 2003, 13:10 |
Low mach number
|
#1 |
Guest
Posts: n/a
|
Hi,everyone Simple question. Why can't we solve the low mach number flow by compressible navier-stokes code.
Someone say, bacause range of eigen value of flux jacobian (eg. U+C>>U>>U-C) is broaden. And preconditioning method adjusts magnitude of eigenvalue. I can't understand above reason. Give me a advice please. thanks kei-tee |
|
February 18, 2003, 22:28 |
Re: Low mach number
|
#2 |
Guest
Posts: n/a
|
You can if you solve for the pressure as a primitive variable and use the the proper adimensional quantity to scale it (rho*u*u or (p-pinf)/(rho*u*u) ).
A good reference on this subject is: Principles of Computational Fluid Dynamics. Author: Wesseling (Very good book). |
|
February 19, 2003, 04:02 |
Re: Low mach number
|
#3 |
Guest
Posts: n/a
|
A low Mach number flow (weakly compressible) is hard to solve when you use a code which solves for density (as a lot of high speed Euler codes do). For low Mach numbers the density doesn't change (much) so this is the wrong variable to solve for. pressure based codes will not have a problem with these flows as the pressure does change. There is no point in solving for density in an incompressible case (density is constant anyway). Low Mach number flows tend to go to this limit.
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
pre-conditioning for low mach number compressible flow solver | Shenren_CN | Main CFD Forum | 0 | April 29, 2011 22:07 |
Development of a Low mach PISO solver | nishant_hull | OpenFOAM Programming & Development | 0 | August 25, 2009 13:48 |
Strong oscillation at transonic mach number | martingariepy | FLUENT | 2 | May 12, 2009 12:40 |
compressible at low Mach number with uniteration | ricklee | Main CFD Forum | 2 | October 21, 2005 00:15 |
Multicomponent fluid | Andrea | CFX | 2 | October 11, 2004 06:12 |