CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Parallel airfoils - Negative drag coefficient

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

LinkBack Thread Tools Search this Thread Display Modes
Old   April 10, 2017, 11:59
Default Parallel airfoils - Negative drag coefficient
New Member
Fernando Avelino
Join Date: Apr 2017
Location: Sao Jose dos Campos, Brazil
Posts: 6
Rep Power: 7
godeny_mecaer is on a distinguished road
Hello everybody!

I'm doing some simulations in FLUENT to study aerodynamic interference between two parallel airfoils (as the attached image), varying AoA, separation of the airfoils and the Reynolds number. Also, I'm using Spalart-Allmaras model for turbulence (in fact, I'm more interested in viscous effects, since I wasn't getting the laminar model to converge) and incompressible flow.

After a series of simulations, I checked the force report in FLUENT and it shows the drag coefficient due pressure and viscosity for both airfoils, and all of them are positive, except for the coefficient due pressure in the upper airfoil. I also checked the lift coefficients and they're OK.

The mesh is fine enough and the direction of the drag vector is correct (I think so). I tried to simulate the airfoils very spaced form each other and the results were similar to just one airfoil alone.

Any idea?
Attached Images
File Type: png airfoils.png (2.1 KB, 3 views)
godeny_mecaer is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Explicitly filtered LES saeedi Main CFD Forum 16 October 14, 2015 11:58
simpleFoam parallel AndrewMortimer OpenFOAM Running, Solving & CFD 12 August 7, 2015 18:45
Why the drag coefficient has negative value? suiede STAR-CCM+ 3 December 4, 2013 06:36
Lift & drag coefficient for NACA airfoil's for VAWT application akku Main CFD Forum 0 April 3, 2013 02:36
Great lift coefficients but negative drag coefficient?! nez FLUENT 0 November 28, 2011 13:57

All times are GMT -4. The time now is 02:45.