VTK - computeVelocity with GuoExternalForceBGKdynamics

Hello Everyone!

I have a question concerning the vtk velocity output using the GuoExternalForceBGK dynamics. I’m using the following line of code to write the velocity values into the vtk file:

vtkOut.writeData<3,float>(*computeVelocity(lattice), “velocity”, 1.0);

Having the above mentioned dynamics type the newly computed velocity is being shifted by “force/2”, resulting in the equilibrium velocity needed for the computation of the forced collision operator. As I’m just doing the analysis and not re-implementing the forcing scheme, the vtk velocity values are incorrect (shifted by “force/2”).

Is there any analogue to the OpenLB’s getVelocity() function, which simply extracts the velocity values and doesn’t compute them again? Thank you.

Best Regards,