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-   -   Pressure around an airfoil in boundary-fitted coordinates (https://www.cfd-online.com/Forums/main/107501-pressure-around-airfoil-boundary-fitted-coordinates.html)

 nw_ds September 28, 2012 15:16

Pressure around an airfoil in boundary-fitted coordinates

I am trying to solve the viscous flow around an airfoil NACA 0012 using the vorticity streamfunction formulation in boundary-fitted coordinates , I have managed to find the velocity field everywhere but I can't seem to find a way to calculate the pressure field around the airfoil or at least on its surface to calculate the lift.

I have tried many things no thing seems to work. I started to doubt the velocity field,but the velocity field looks correct but I am not sure anymore.

So I would appreciate it if anyone can get me a version of the pressure equation ( static or total ) in boundary fitted coordinates with the appropriate boundary conditions

 michujo September 29, 2012 12:27

Hi, this answer might seem a little dumb but, can't you use Bernouilli equation to calculate pressure at every point?

Where and are the pressure and velocity modulus far upstream of the airfoil.

This is valid for a incompressible flow (M<0.3). If your flow is compressible then you'll have to use the compressible version of the expression.

I don't think the fact that you're using body-fitted coordinates changes anything, you just calculate p (or p-p_infinity) at every point of your domain.

Cheers,
Michujo.

 nw_ds September 30, 2012 10:06

Thanks but that's not what i am looking for

 michujo September 30, 2012 11:21

I don't know if you speak spanish but you might want to check this MSc. Thesis. The algorithm to compute pressure (along with the appropriate boundary conditions) in body-fitted coordinates is all explained.

http://e-archivo.uc3m.es/bitstream/1...ranjo_2009.pdf

What she does essentially is to compute pressure at every point from the computed velocity field, regardless of the system of coordinates.

Could you explain your question a little bit more in detail?

Cheers,
Michujo.

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