CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

Pressure around an airfoil in boundary-fitted coordinates

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 28, 2012, 15:16
Default Pressure around an airfoil in boundary-fitted coordinates
  #1
New Member
 
Mido
Join Date: Mar 2011
Posts: 19
Rep Power: 6
nw_ds is on a distinguished road
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
nw_ds is offline   Reply With Quote

Old   September 29, 2012, 12:27
Default
  #2
Senior Member
 
Join Date: Dec 2011
Location: Madrid, Spain
Posts: 133
Rep Power: 6
michujo is on a distinguished road
Hi, this answer might seem a little dumb but, can't you use Bernouilli equation to calculate pressure at every point?

p_{\infty}+\frac{1}{2} \cdot \rho U_{\infty}^2=p+\frac{1}{2} \cdot \rho U^2

Where p_{\infty} and U_{\infty} 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.

Was this answer helpful?

Cheers,
Michujo.
michujo is offline   Reply With Quote

Old   September 30, 2012, 10:06
Default
  #3
New Member
 
Mido
Join Date: Mar 2011
Posts: 19
Rep Power: 6
nw_ds is on a distinguished road
Thanks but that's not what i am looking for
nw_ds is offline   Reply With Quote

Old   September 30, 2012, 11:21
Default
  #4
Senior Member
 
Join Date: Dec 2011
Location: Madrid, Spain
Posts: 133
Rep Power: 6
michujo is on a distinguished road
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.
michujo is offline   Reply With Quote

Reply

Thread Tools
Display Modes

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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
domain imbalance for enrgy equation happy CFX 14 September 6, 2012 01:54
Domain Reference Pressure and mass flow inlet boundary AdidaKK CFX 12 February 11, 2010 21:28
RPM in Wind Turbine Pankaj CFX 9 November 23, 2009 05:05
Pressure Boundary Problems Chris CD-adapco 2 June 21, 2005 08:20
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 22:02


All times are GMT -4. The time now is 14:34.