Help setting angular velocity in rad/s

[galinaDor]

excuse me for the very basic question: I am checking the Cessna example in the setup.cpp file. I would like to set the angular velocity of the rotor in rad/s but I am not able to understand how to do it.

[ProjectPhysX]

Hi @galinaDor,

check the Bell 222 setup here as a better example.
The conversion goes like this: rotation speed in RPM or rad/s --> bladetip velocity in SI units --> blade tip velocity in LBM units (should not be >0.1) --> rotation speed in rad/(LBM time step).

Kind regards,
Moritz

[galinaDor]

thanks very much, it was usefull.
I still am having difficulties understanding why you are defining si_rpm (from which si_u is afterwards derived) ... I see that later on the angular velocity of the two rotating parts is defined in lbm and radius of the components.

[galinaDor]

or is it possible to set oblique (not y direction only) streamwise velocity?

[ProjectPhysX]

You can also start from rad/s instead of rpm.

For non-axis-aligned rotation, just set the vector of angular velocity (points in the direction of rotation axis) accordingly in lbm.voxelize_mesh_on_device and mesh->rotate.

[galinaDor]

I am not sure I can use a rpm not aligned with the streamline velocity (u/radious)