There are much more on our website: conself.com/blog/category/post-processing/

I am newer working with CFD. you can explain for me why lift = pressure * scalars y. I mean I can understand what is the scalars y. thank you .

@@HoaiThanh-wm6ze In this case, his model is set up with y axis being vertically up. So NORMAL_Y is a scalar value, it's the component of the normal of each element in the vertically up direction. Pressure times that component is the force on that cell. Add up all the forces on all the cells to get the total.

I think I agree with you, but I am not sure. To get the total lift force the pressure load on the mesh face should be multiplied with the mesh face area.

@@lucderuiter8904 To be more precise, if you change angle of attack with velocity vectors this procedure will give Normal and Axial force. On the other hand, if you change angle of attack by body rotation it wil give Lift and drag force.

So, the tutorial doesnt give dragCoeff? How can I obtain dragCoeff?

It's a late answer and you surely have figured it out by now, but for reference you need to have or compute the wall shear stress then include them in the calculation of the forces

yeah, STL are easy to import in our web application. If you want we can set up a custom tutorial for you!

I hope I'm not late. Yo have tu clivk in your .foam and then scroll down until you see your mesh regions. the you have to enable your surface.

Yeap, u r right one need to muliply pressure by density, to get actual force value

Hello I am also facing the same problem..did you find a solution to it..

I know this is old, but the solution is selecting openfoam reader from just above where the extract block filter appears in the tree in the top left and making sure the cut or wall that represents the aircraft is selected then hitting apply

well, in CFD everything is calculated and then it is up to the user considering or not these effects

Hai sir/madam i am also getting the same error. If you know how to correct the mistake please explain. Advanse Thanks.

Sorry for the late reply. Anyway, the procedure in paraview is exactly the same. The only thing you have to change in your CFD simulation is the geometry configuration!

One simple thing one could do is to maintain the flow speed aligned with the simulation main reference frame and turn the geometry accordingly around the right axis. Otherwise you con project your velocity component inside paraview using the calculator filter.

I thought about turning the geometry, but I don't like that solution. I don't quite understand what you mean by projecting the velocity component. Projecting it where?

If your inlet velocity is slightly inclined with respect to the system of reference you can define a new system of reference that is aligned with the velocity, and then calculate the velocity components with respect to it, projecting them onto it. This means you have to compute the proper coordinate transformation via the cosine matrix and project the velocity vector. But you have to pay attention also to how surface normals are defined in such a case, since they are vector too, you should take it into account in the new system of reference. So probably turning the CAD can be the most straightforward way.

But can't I just calculate it as if I didn't have an inflow angle and add both, which should give me the resulting force vector? And then I can just take out the drag and lift components depending on my own frame of reference.

It can be a solution, it should work. You can calculate lift & drag for a 0 angle geometry and inflow, then rotate both the geometry and the flow inclination and use your approach to verify if it works.