# k-w SST model wall conditions

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

 March 11, 2005, 07:24 k-w SST model wall conditions #1 Sheila Guest   Posts: n/a Hello everyone, I am writing my own code for SST model and comparing the data with that given by STAR. Frustratingly enough, I cant match them. Acording to the manuel and STARs data, the w and viscosity of the near wall cell is fixed. When I carry out my calculation, it seems like the near wall k value is very small compared to that given by STAR. And also, the vorticity is VERY small relative to STARS value. From this I deduced that STAR is using some kind of WALL treatment which is not mentioined in the manuels. I wonder if anyone knows what that is or can direct me in the right direction. My velocities along y direction are similar to that of STAR, so I dont see how near wall vorticity can be so different. Please help.... Sheila

 March 11, 2005, 15:57 Re: k-w SST model wall conditions #2 4xF Guest   Posts: n/a As far as I understood, omega is not the vorticity, but rather the specific dissipation rate which has the dimension of a frequency... Are we talking about the same?

 March 11, 2005, 18:54 Re: k-w SST model wall conditions #3 Sheila Guest   Posts: n/a Hi 4xF, yeh, you are right, w is the dissipation rate, which is fixed for the near wall cell. Vorticity, or rather the magnitude of vorticity comes into action in the equation for the turbulent viscosity. Thats why I have it in my data file. I used the VELGRD to calculate the velocity gradients from which I can calculate the vorticity. Any idea on the wall condition or anything why the results dont match? I am pretty sure my implementation is correct. I have also checked it with someone with high authority in CFD. Thanks. Sheila

 March 11, 2005, 19:06 Re: k-w SST model wall conditions #4 Pauli Guest   Posts: n/a A wild guess - non-equilibrium vs equilibrium wall functions.

 March 12, 2005, 04:55 Re: k-w SST model wall conditions #5 Sheila Guest   Posts: n/a I am using low Reynolds number version of kw SST.

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post sivaramakrishnaiah CFX 2 August 21, 2008 10:25 Ana Raquel Rosado FLUENT 3 November 8, 2006 23:18 Robin K CFX 0 June 28, 2005 20:51 sourav FLUENT 1 October 24, 2004 21:38 Lior FLUENT 3 September 23, 2004 16:10

All times are GMT -4. The time now is 15:15.