Torque calculation

[QuentinMercier]

Hello Everyone

Here i come because i have some trouble with a torque calculation on a simple problem. My purpose is making simple modification on a savonius wind turbine to kill the dead angle but i have some trouble with the torque calculation.

Here is a picture that illustrate my problem

Boundaries: plan(y=0)=> pressure=1bar and velocity=5m/s

                    plan(y=468)=> pressure=1bar

Here you ca see i have a torque (M_o1) of 4Nm (which should be near 0), but look at the forces!! let's do the torque calculation together: -M_o2=y.Fz-z.Fy         y=(y(o)-y(application point of my force)) same for z

                                  -o=(---,-40,0)

So M_o2=0.18*1.2*10^(-3)+0.04*8*10^(-3)<<<<M_o1.

I can't explain that 4Nm calculation, here is what I have done to test and solve my problem:

-> modify boundaries (putting pressure all around the part)

->reconstruct a simple geometrie with strait cylinders

->solve step by step (one cylinders, then solve, good results, then 2nd cylinder, then solve, then BUG)

But always the same weird result....

Something you need to know moreover! When i put the velocity to 0m/s....the torque calculated by the solver is .... 4Nm!!! I have my perpetual movement here.

Does anyone have an idea, would be so cool?

I'm totaly blocked.

Quentin

[QuentinMercier]

Hello everyone,

Here are some news about my problem.

First of all, this weird torque was due to my boundaries conditions: I tried to put a 1Pa instead of 1bar pressure and this weird torque just disappeared. But I can't understand this phenomenum, does anyone have any explication to that?

Technically, puting 1Pa instead of 1bar must not change anything (Navier Stockes).