Turn off velocity Equations
Dear all,
I want to seek a suggestion to turn off the velocity equations, i.e. fixed U, V, W, for the Solver run. Anyone can help me? Thank you. Nelson 
Re: Turn off velocity Equations
Which solver are you using?
In CFX5 you can set fluids = f in the expert parameters. In TASCflow, in the PRM file: fluids = f; turbmd = f; tmptre = f will turn of the fluids, turbulence and energy equations respectively. In CFX4, I don't know how to do it. Regards, cfd guy 
Re: Turn off velocity Equations
Hi, excuse my ignorance please.I would like to know when & why it is suitable to turn off these eqs?

Re: Turn off velocity Equations
I can be helpfull if you want to calculate different temperatures or (passive) scalars distributions at a given flow field. Provided they do not disturb your flow field, that's what you assume..
Astrid 
Re: Turn off velocity Equations
In CFX 4 you can turn off UVW and p with the keyword:
ITERATIONS OF HYDRODYNAMIC EQUATIONS 0 in the subject: >>SOLVER DATA >>PROGRAM CONTROL Astrid 
Thank you ,Astrid

Re: Turn off velocity Equations
I use to turn off all equations (turbulence, fluids and energy) when I'm testing a new moving grid with the TASCFlow code.

Re: Turn off velocity Equations
I very often use this approach when dealing with combustion or heat transfer problems. I have noticed in such problems that the velocity and pressure field might have converged or does not change anymore but the residuals for the temperature/enthalpy is still decreasing. It can take very long time, many iterations, for settling the solution for the temperaure, solving the velocity and pressure just increase the computational time. So I normally get a converged solution on the velocities and then do a restart without solving the velocities. I have found this to be very efficient.

Re: Turn off velocity Equations
When you put fluids = f in tascflow, the momentum as well as continuity equations are turned off. Is it possible to just turn of momentum or continuity equation selectively, or even better, u, v, or w componets of momentum equations separately? I normally get mass converged very quickly but one particular momentum equations (W in my case as the main flow direction is Z) takes time to solve.
Thanks 
All times are GMT 4. The time now is 23:10. 