CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

Initial pressure and transverse velocity fields to initialize turbulence model

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

LinkBack Thread Tools Display Modes
Old   February 29, 2012, 11:11
Default Initial pressure and transverse velocity fields to initialize turbulence model
New Member
Nikolay Vinnichenko
Join Date: Nov 2010
Posts: 14
Rep Power: 6
nickvinn is on a distinguished road
Surprisingly, I have certain difficulties in unsteady simulations of turbulent boundary layer over flat plate using Spalart-Allmaras model.
If I fix the velocity field and calculate eddy viscosity, the final field is realistic. Moreover, if I solve energy equation for temperature then, using constant Prandtl number and eddy viscosity obtained, heat exchange is accurate. So, probably, realization of Spalart-Allmaras model equation is OK.
Solving continuity and momentum equations was tested for laminar case and it is OK too.
But: if I calculate first eddy viscosity for the fixed velocity field and then begin solving momentum and continuity equations, the fields escape from the correct solution. The reason is that the initial pressure field must correspond to those of velocity and eddy viscosity, so that the solution is stationary.
Ok, the question : How can I find this initial pressure and, perhaps, transverse velocity fields? At the moment I'm making use of solving numerically continuity dv_x/dx+dv_y/dy=0 to obtain transverse velocity and then x-momentum in the form dp/dx=... with p(0, y)=const for the pressure field. This results in pressure variations in transverse direction and program falls at the very first time step. Is there any other way to find pressure field or I should examine just the approximation of these equations?
nickvinn is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11

All times are GMT -4. The time now is 13:29.