Sometimes a simulation does not have a pressure specification set through the boundary conditions. In this case, the solver automatically sets a pressure level at a reference location. By default, the reference value is zero, and the reference location is at the first finite volume number. There are two methods to override this default behavior if necessary.

The first (and recommended) method is to set a pressure level using the Pressure Level Information option on the Solver Control form in CFX-Pre. The Cartesian coordinates option enables you to specify an X, Y, Z location for the reference pressure location. The nearest node to this location is used as the pressure reference location. A value for the reference pressure can also be entered.

The Compressible Transient Option determines whether the pressure field is shifted to accelerate mass conservation for compressible transient simulations that have no pressure boundaries.