[jaiswal]

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

[kmandar]

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

[fpalacios]

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