CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   Main CFD Forum (http://www.cfd-online.com/Forums/main/)
-   -   NO STAGNATION POINT FOR AIRFOIL SIMULATION (http://www.cfd-online.com/Forums/main/14708-no-stagnation-point-airfoil-simulation.html)

Rif January 29, 2008 10:57

NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
Hi, I'm running an airfoil simulation on a cfd code,SWIFT. does anybody know why i cannot get a stagnation point at the leading edge of my airfoil? The velocity at the leading edge should be 0 m/s but i cannot seem to get this in my simulations. i'm running for AOA 0 degrees at high Reynolds number. what can possibly cause my simulation to have no stagnation point at all?

Cheerios Rif

Mani January 29, 2008 11:13

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
Very weird!

ag January 29, 2008 14:26

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
I would guess that the boundary conditions have either not been specified or have been specified incorrectly.

Mani January 29, 2008 17:00

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
Have you specified the airfoil as wall? Again i agree with ag something is wrong with BC.

Mani

Simon January 29, 2008 17:47

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
What type of mesh typology are you using. I would need to look at your mesh before i can say anything. Can you e-mail it to me on cfd.student@gmail.com.

Simon

Simon January 30, 2008 07:42

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
Mesh is indeed not a very good one as you mentioned in your e-mail. However, it should still give you a stagnation point. Your boundary conditions also ok. Mind boggling

Glenn February 4, 2008 08:33

Re: NO STAGNATION POINT FOR AIRFOIL SIMULATION
 
Two thoughts for your consideration on this... 1) Are you seeing the flow vectors splitting and heading towrads the pressure and suction side of the airfoil at the leading edge? If so, stagnation falls in between this split direction vectors...but if you mesh is coarse there, you may not have any mesh points to capture the actual fidelity of a stagnation point. 2) If you do not see the vectors splitting towards the pressure and suction sides, it is possible your stagnation point exists on the airfoil pressure side, slightly downstream of the leading edge. You may be experiencing a scenario where the flow wants to head around the suction side so strongly, relative to the pressure side, that the approach flow is vectorially re-oriented towards the suction side and stagnation is occuring off the leading edge onto the pressure side.

Check your solution to see if either of these scenarios makes sense to your specific problem.


All times are GMT -4. The time now is 17:08.