Using Cp polynomial

Idanst · July 23, 2024, 02:39

Hello,

I am looking to simulate a real gas using a Cp(T) polynomial instead of the constant value of 1004.703 J/kg*K for air.

I noticed a line for CP_POLYCOEFFS in the template SU2 file, but I couldn't find any information on how to enable it. Can this be used with the STANDARD_AIR fluid model, or do I need to select a different model?

Thanks,

bigfootedrockmidget · July 23, 2024, 14:54

It can be used when you set the fluid to incompressible polytropic gas.

From config_template.cfg:

Code:

% ---- IDEAL GAS, POLYTROPIC, VAN DER WAALS AND PENG ROBINSON CONSTANTS -------%
%
FLUID_MODEL= INC_IDEAL_GAS_POLY
SPECIFIC_HEAT_CP= 1004.703
MOLECULAR_WEIGHT= 28.96
CP_POLYCOEFFS= ( 1004.703, 0.1, 0.0, 0.0, 0.0)

An example can be found in Testcases/incomp_navierstokes/cylinder/

Idanst · July 24, 2024, 02:27

Thank you!

I am looking to simulate compressible flow at high Mach numbers, around Mach 5. Could you recommend a more suitable fluid model for this scenario? I plan to account for variations in the heat capacity ratio caused by the high pressures and temperatures.

bigfootedrockmidget · August 1, 2024, 17:49

Hi, sorry for the long wait, so you could maybe also use the NEMO solver, which targets hypersonic flows. There are some examples in the testcases repository.

Idanst · August 8, 2024, 08:08

I'll check it, thank you

July 23, 2024, 02:39	Using Cp polynomial	#1
Idanst New Member Join Date: Nov 2017 Posts: 7 Rep Power: 9	Hello, I am looking to simulate a real gas using a Cp(T) polynomial instead of the constant value of 1004.703 J/kg*K for air. I noticed a line for CP_POLYCOEFFS in the template SU2 file, but I couldn't find any information on how to enable it. Can this be used with the STANDARD_AIR fluid model, or do I need to select a different model? Thanks,

July 23, 2024, 14:54		#2
bigfootedrockmidget Senior Member bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 657 Rep Power: 19	It can be used when you set the fluid to incompressible polytropic gas. From config_template.cfg: Code: % ---- IDEAL GAS, POLYTROPIC, VAN DER WAALS AND PENG ROBINSON CONSTANTS -------% % FLUID_MODEL= INC_IDEAL_GAS_POLY SPECIFIC_HEAT_CP= 1004.703 MOLECULAR_WEIGHT= 28.96 CP_POLYCOEFFS= ( 1004.703, 0.1, 0.0, 0.0, 0.0) An example can be found in Testcases/incomp_navierstokes/cylinder/

July 24, 2024, 02:27		#3
Idanst New Member Join Date: Nov 2017 Posts: 7 Rep Power: 9	Thank you! I am looking to simulate compressible flow at high Mach numbers, around Mach 5. Could you recommend a more suitable fluid model for this scenario? I plan to account for variations in the heat capacity ratio caused by the high pressures and temperatures. ShengZhang likes this.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Fluent UDF - polynomial profile description	mihnea333	FLUENT	0	February 26, 2021 04:19
Error: GENERAL CAR CDR - User-Defined-Material-Database	EvaKn	FLUENT	0	December 21, 2020 09:01
Add piecewise polinomial material property	EvaKn	FLUENT	0	December 21, 2020 07:03
thermophysicalProperties with polynomial values	Gerrit	OpenFOAM Running, Solving & CFD	4	April 21, 2020 11:51
polynomial BC from 3d vector data	map	OpenFOAM Programming & Development	0	March 30, 2015 09:48

August 1, 2024, 17:49		#4
bigfootedrockmidget Senior Member bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 657 Rep Power: 19	Hi, sorry for the long wait, so you could maybe also use the NEMO solver, which targets hypersonic flows. There are some examples in the testcases repository.

August 8, 2024, 08:08		#5
Idanst New Member Join Date: Nov 2017 Posts: 7 Rep Power: 9	I'll check it, thank you