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 Bortolazzi July 23, 2013 09:42

Drag under Euler formulation

Hi developers,

I would like to ask you how the drag of a profile is computed using Euler analysis. In another post, I've been told the total drag was computed by integrating over the surface, but how is the shear stress tension localy computed?
Are the concepts of displacement thickness and momentum thickness employed?

Andre

 fpalacios August 19, 2013 12:32

Hi Andre,
To compute the Drag (inviscid and viscous) we perform a direct integration of the forces on the surface. More details in http://su2.stanford.edu/documents/SU2_AIAA_ASM2013.pdf

And the subroutines in the code:
void CEulerSolver::Inviscid_Forces(CGeometry *geometry, CConfig *config)
void CNSSolver::Viscous_Forces(CGeometry *geometry, CConfig *config)

Best,
Francisco

Quote:
 Originally Posted by Bortolazzi (Post 441503) Hi developers, I would like to ask you how the drag of a profile is computed using Euler analysis. In another post, I've been told the total drag was computed by integrating over the surface, but how is the shear stress tension localy computed? Are the concepts of displacement thickness and momentum thickness employed? Thanks in advance, Andre

 Bortolazzi August 20, 2013 08:14

Hi Francisco,

Thanks for your reply. In the end, I guess I was just strugling with spurious drag, because SU2 provided some small values for drag coefficient when running a bidimensional Euler analysis in low Mach flow (thus, no drag). I was confused, because the spurious drag was increasing with the angle of attack, but after some research, I found out this is the normal behaviour for numerical drag.