SU2 config file solver settings (Dimensional vs freestream_press_eq_one)
 

Hi all,

In SU2 config file solver settings, I am confused regarding flow non-dimensionalization. When should i use dimesional or when should i use freestream_press_eq_one? what is the difference? Will the results be different for both of them?

These are the lines from the SU2 config file:
% Flow non-dimensionalization (DIMENSIONAL, FREESTREAM_PRESS_EQ_ONE,
% FREESTREAM_VEL_EQ_MACH, FREESTREAM_VEL_EQ_ONE)
REF_DIMENSIONALIZATION= FREESTREAM_PRESS_EQ_ONE

Thanks in advance

Hi,

You may want to look at
CEulerSolver::SetNondimensionalization in solver_direct_mean.cpp

which has the equations for nondimensionalization.

Here is related thread.

Hope this helps,
Mandar

Remember that some numerical algorithms have been designed to work with nondimensionalized values. Our recommendation is to use FREESTREAM_PRESS_EQ_ONE.

When you run the code you can see the effect of the non dimensionalization in the console output.

For example:

Free-stream static pressure: 101325 Pa.
Free-stream total pressure: 154454 Pa.
Free-stream temperature: 273.15 K.
Free-stream density: 1.29225 kg/m^3.
Free-stream velocity: (264.994, 5.78219) m/s. Magnitude: 265.057 m/s.
Free-stream total energy per unit mass: 231152 m^2/s^2.
-- Reference values:
Reference specific gas constant: 287.058 N.m/kg.K.
Reference pressure: 101325 Pa.
Reference temperature: 273.15 K.
Reference density: 1.29225 kg/m^3.
Reference velocity: 280.018 m/s.
Reference energy per unit mass: 78409.9 m^2/s^2.
-- Resulting non-dimensional state:
Mach number (non-dim): 0.8
Specific gas constant (non-dim): 1
Free-stream temperature (non-dim): 1
Free-stream pressure (non-dim): 1
Free-stream density (non-dim): 1
Free-stream velocity (non-dim): (0.946348, 0.0206494). Magnitude: 0.946573
Free-stream total energy per unit mass (non-dim): 2.948

Maybe you can play with the different kinds of non-dimensionalization, and look at the console output.

Best,
Francisco