For a quasi-compressible option, density and energy are assumed to be constant. No convection-diffusion is computed:

Therefore, the performance is improved and less computation time is needed.

The quasi-compressible option can be activated in the RADIOSS Engine file by:

/INCMP

Using this option, the acoustic waves propagate as accurately as in the compressible case. However, it cannot be combined with the turbulence model.