[fernexda]

Dear all,

I'm currently computing forces around a body, but the forces are surprisingly high, therefore I'm trying to review every aspects to check if those values are realistic. Two things are still unclear :

1.Pressure : I was wondering if the boundary and initial values of the pressure matter. What I did until now is apply a zeroGradient on the Inlet, and p=0 on the outlet. But since the simulation takes place at atmospheric conditions, shouldn't I impose p=p_atm on the outlet ? Would that make any difference ? Would it affect either the viscous forces or the pressure forces ? In what manner ?

2.Density : I don't know the influence of the density on the resulting forces (viscous and pressure forces). As far as I know, the only place where I can choose the density is in the forces dictionary where I have the two following lines :

rhoName            rhoInf;
rhoInf                1;

Should I change this value to make it equal to my fluide density (which is equal to 1.225 kg/m³) to get the real forces ?
And does this value have anything to do with the input values (boundary conditions for U, p, viscosity) ?

Thanks a lot for any answer !

Daniel