Pressure field in LBM about fluidx3d HOT 1 CLOSED

Hi @mohdafeefbadri,

yes you have access to the pressure field: pressure in LBM is directly proportional to density (simulation is isothermal). The proportionality constant is c², with c=1/sqrt(3) being the LBM speed of sound.

In LBM units you have the pressure for any lattice point n: float lbm_p_n = lbm.rho[n]/3.0f;.
In SI units, it's float si_p_n = units.si_p(lbm.rho[n]/3.0f); with prior unit conversion via units.set_m_kg_s(...);.

For external data evaluation, you can .vtk-export the volumetric density field in LBM units via lbm.rho.write_device_to_vtk(); and also export the conversion constant from (density in LBM units) --> (pressure in SI units) which is float conversion_constant = units.si_p(1.0f/3.0f);.

All the best with your study!

Kind regards,
Moritz

from fluidx3d.