# Pressure distribution

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 December 7, 2001, 05:01 Pressure distribution #1 Lennart Wern Guest   Posts: n/a Hi evereybody I am interested in studying pressure distribution on different objects. Is there anyone that know which turbulence model, differencing scheme and solution algorithm is best to use? The K-E model seemes to overpredict the pressure at the stagnation point a lot. I am also interested in studying the frequency of the von Karman's vortex street in transient analysis. Is there anyone that know which turbulence model, differencing scheme and solution algorithm is best to use in this case? Regards Lennart

 December 7, 2001, 06:41 Re: Pressure distribution #2 john Guest   Posts: n/a It seems that the best combination is: cubic k-e turbulence model (especially the lower Reynolds number version if you can afford the mesh density near wall) and MARS scheme for convection term discretisation. The solution algorithm should not afttect converged results. The v2f model is very good - but you have to pay for it since it's an external model from Standford. CD should be able to send you its case of flow pass the square cylinder with von Karman vortex. It seems K-e model is good enough to do it with above 95% blending between Centeral and upwind schemes. But you have to have reasonable mesh density around the obstacle to resolve the vertex. Also set your upstream boundary (inlet?) far enough from the obstacle with proper profile of boundary condition.

 December 11, 2001, 09:46 Re: Pressure distribution #3 Lennart Wern Guest   Posts: n/a Hi John Thank you for your answer. I have tested different turbulence models (heigh Reynolds only) and MARS. I have compared the Cp-factor at the stagnation point. As I think you know Cp = (P-Pref) / (½·Rho·U·U) Theoretically it should be 1.0 at the stagnation point. My little test givs that the RNG turbulence model gives the best result. It was also much easier to get STAR to converge with RNG than "Cubic Heigh Reynolds". Wth the standard K-E model I got the highest (=worst) values. Have you compared the pressure calculated with STAR with measurements?

 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 sometime1990 CFX 1 November 13, 2008 09:08 sam CFX 1 September 13, 2008 17:09 DAK565656 CFX 4 September 21, 2005 08:20 Sham FLUENT 3 August 23, 2005 01:16 Achilleas Tsompanos Main CFD Forum 0 March 7, 2000 11:50

All times are GMT -4. The time now is 19:30.

 Contact Us - CFD Online - Privacy Statement - Top