|May 21, 2015, 13:40||
Porblem getting resonable results using KomegaSST for an airfoil case
Join Date: Nov 2010
Location: United States
Posts: 186Rep Power: 8
I have been using OpenFoam for about four months so far. I’ve learned the basics through some tutorials and I’ve been recently trying to obtain some good results for a 2D airfoil case.
I’m using simpleFoam with both Spalart-Almaras and kOmegaSST turbulence models to simulate the flow around a NACA 0015 airfoil (Reynolds number approximately 2.575*10^6 and 0 degrees angle of attack). After finishing the grid convergence study, which gave a value of Cd = 0.016 at zero mesh spacing, I have obtained values of Cl and Cd 1.042858e-03 and 1.675878e-02 respectively. The experimental result, especially for Cd shows a value of 1.4e-02. However, after finishing the validation using Spalart-Almaras, I am unable to get reasonable results when I switch to KomegaSST turbulence model.
I’m really asking for some help.
This is how the mesh looks like in Paraview:
I’m using freestream BC for U both at inlet and outlet, and obviously zero velocity condition on airfoil patch.
For p, freestreampressure at inlet/outlet and zerogradient on airfoil.
For k, freestream BC at inlet/outlet and fixedValue on airfoil.
For omega, freestream BC at inlet/outlet and fixedValue on airfoil.
For nut, calculated BC at inlet/outlet and fixedValue on airfoil.
Down here you’ll find the complete case directory with all the files
|May 22, 2015, 06:16||
Join Date: Dec 2011
Location: Bristol, United Kingdom
Posts: 196Rep Power: 6
What is your Y+ value and did you try your cases with and without wallfunctions ?, In my experience this factor is one of the most important for validation Please have a look here http://www.cfd-online.com/Forums/ope...provement.html
What is the final validation you are trying to acheive ? just Cl/Cd or Cp and boundary layer growth aswell ?
If you want Cp and boundary data aswell did you consider them during mesh independency study
"Real knowledge is to know the extent of one's ignorance." - Confucius
|Thread||Thread Starter||Forum||Replies||Last Post|
|Unphysical Results of Low-Re Airfoil Simulations||ericthefatguy||SU2||2||February 2, 2015 06:07|
|How to build current blower fan model in Flotherm||eric0722||FloEFD, FloWorks & FloTHERM||1||January 27, 2015 03:06|
|Free surface boudary conditions with SOLA-VOF||Fan||Main CFD Forum||10||September 9, 2006 12:24|
|oscillating airfoil test case||Akbar||Main CFD Forum||1||July 22, 2005 11:49|
|flow simulation across a small fan||jane luo||Main CFD Forum||15||April 12, 2004 17:49|