Confusion about pressures in CFX5.6

Forrest

Hi, everyone

I am modelling natural convection flow in a simple rectangular box with openings connected to external. Buoyancy model with Boussinesq assumption is used. I am getting confused about the different types of pressures in CFX5.6.

It says on page 10 of Solver Modelling menu: "Note that the Results file 'pressure' values do not contain the hydrostatic contribution to 'pressrue', and this should be added to obtain actual values of pressure relative to the 'Reference Pressure' in these cases. If the flow is buoyant and the 'Reference Pressure' is set to 0 Pa, then the hydrostatic pressure contribution will be included".

1. is this true if you set 'reference pressure = 0' then the dydrostatic pressure contribution is automatically included?

2. What is the 'pressure' in the results file? Is it the 'Modified Pressure' defined as: P_stat + 2*rho*k/3 ?

3. Is the 'total pressure' in the results file defined as: P_tot =P_stat + 0.5*(U*U)? then what is the difference between the 'total pressure' and the 'modified pressure'?

4. Which pressure value is representing the natural driving force?

5. I understand that in CFX4 the 'modified pressure' was further modified to P_modified = P_stat + 2*rho*k/3 –rho_ref*g*xi. when using eddy viscosity models. Then the scalar 'Real Pressure' will represent its value in output file. Am I right?

Thank you very much for your help

Regards Forrest