Ahmed Body Drag Validation Problem

[DaleKramer]

@Ricardopg

this is what intuitively makes sense to me

There were a lot of people who intuitively thought the world was flat

I am trying to take intuition out of the picture… As I said, I would LIKE to find out that I have made a mistake by not magically multiplying my integration results by -1. It will take more than intuition to convince me that I should multiply by -1.

@Ricardopg

• If you take viscous forces as positive, then the resulting drag force = 0.7437 + 0.00055 N (viscous + pressure).
• If you take viscous forces as negative (integrating y wall shear stress on paraview), then the resulting drag force = - 0.7437 + 0.00055 N (viscous + pressure), which happens to be lower than zero.

Could you provide a link to the sim run that gave you those results?

@Ricardopg

It doesn’t make sense because negative drag would imply that the flow is gaining energy between the inlet and outlet.

Could you calculate for me the energy that is gained here?