# Forces Calculations

I’m doing an incompressible flow sim called “1 Moderate Incompressible (Average Wind Speed Crosswinds)”. I’m confused about some of the results that came from the forces calculations. https://www.simscale.com/workbench/?pid=1777385904090276987&mi=spec%3Ae30e51f9-5a5b-4972-a064-682d18e230b9%2Cservice%3ASIMULATION%2Cstrategy%3A6

So I set the sim to calculate the forces on the entirety of the upper and lower surface. Then, I did the same calculation but where the forces were calculated for each face on the body. When I compare the results, the “total surface force” is about equal to the force calculated on a single face. So I’m confused as my expectation was that the sum of the faces would add up to that of the total surface.

Hi @rafaelg,
could you in detail describe your doubts. I quickly checked the forces and they seem totally coherent.
For example for the lower part of the car we have:
Total lower force: Fx = 178.5N Fy = -308N
---------------------------------------------------------
Front wheels: Fx = 143.2 N Fy = -145.5N
Lower Floor: Fx = 0 N Fy = -108.8 N
Rear wheels: Fx = 36.2 N Fy = -52.3 N
---------------------------------------------------------
Total sum: Fx = 179.4 N Fy = -306.6 N (< 1% diff)

Best,
Richard

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@rszoeke Thanks for the clarification. I think I must’ve just been mixing up values when I was scrolling from surface to surface in the tests list.