Mars Entry Vehicle simulation using NEMO solver

NemanjaJanus · August 2, 2023, 13:15

Hi everyone,

I am performing hypersonic simulations of the Mars Science Laboratory entry vehicle. For this purpose, I am using NEMO NS solver coupled with Mutation++ Library. I created Mars 8 species gas mixture file (the same gas model used by NASA) and a mechanism file using Park-94 reaction rates. The scope of my analysis is to change the shape of the forebody of the capsule to investigate changes in aerodynamic characteristics and heat fluxes. Even though I managed to replicate values of aerodynamic coefficients from the NASA Aerodynamic Database, I would like to also have reliable predictions of heat fluxes, for this reason, I have several questions:

1. Is there any way to include super-catalytic wall boundary condition with a custom-made Mars 8 species gas mixture, fixing mass fraction to the freestream values? I managed to perform simulations using a super-catalytic wall boundary condition with AIR-5 gas model, but when I tried with Mars 8 species mixture, it gave me an error that the boundary condition is not compatible with the selected gas mixture.

2. I noticed that total energy at the freestream is negative for CO2-dominated gas mixtures. This is not the case for AIR-5 at the same freestream conditions, for example. Can the explanation for this be the negative enthalpy of formation for CO2 hence making the term e^o=h^o-p*v in the expression of total energy even more negative?

3. In the paper, Development of Physical and Numerical Nonequilibrium
Modeling Capabilities within the SU2-NEMO Code, I see validation cases using turbulence models with NEMO solver. Are these models also available in the latest version of SU2 within the NEMO framework, or is this something in development? I remember that before, it was stated that turbulence models are not still completely reliable within the NEMO framework and that they are under development. At the moment, since I am using laminar conditions, I get lower values away from the stagnation point with respect to NASA predictions, which is expected since flow over the MSL capsule is turbulent, and hence heat flux is augmented.

bigfootedrockmidget · August 21, 2023, 15:06

I see that nobody answered, I am not a nemo researcher so I only know that nemo+turbulence is in one of the feature branches and is in active development. For the other questions, you would need to ask one of the nemo developers directly, maybe in slack.

August 2, 2023, 13:15	Mars Entry Vehicle simulation using NEMO solver	#1
NemanjaJanus New Member Nemanja Janus Join Date: Aug 2023 Posts: 1 Rep Power: 0	Hi everyone, I am performing hypersonic simulations of the Mars Science Laboratory entry vehicle. For this purpose, I am using NEMO NS solver coupled with Mutation++ Library. I created Mars 8 species gas mixture file (the same gas model used by NASA) and a mechanism file using Park-94 reaction rates. The scope of my analysis is to change the shape of the forebody of the capsule to investigate changes in aerodynamic characteristics and heat fluxes. Even though I managed to replicate values of aerodynamic coefficients from the NASA Aerodynamic Database, I would like to also have reliable predictions of heat fluxes, for this reason, I have several questions: 1. Is there any way to include super-catalytic wall boundary condition with a custom-made Mars 8 species gas mixture, fixing mass fraction to the freestream values? I managed to perform simulations using a super-catalytic wall boundary condition with AIR-5 gas model, but when I tried with Mars 8 species mixture, it gave me an error that the boundary condition is not compatible with the selected gas mixture. 2. I noticed that total energy at the freestream is negative for CO2-dominated gas mixtures. This is not the case for AIR-5 at the same freestream conditions, for example. Can the explanation for this be the negative enthalpy of formation for CO2 hence making the term e^o=h^o-p*v in the expression of total energy even more negative? 3. In the paper, Development of Physical and Numerical Nonequilibrium Modeling Capabilities within the SU2-NEMO Code, I see validation cases using turbulence models with NEMO solver. Are these models also available in the latest version of SU2 within the NEMO framework, or is this something in development? I remember that before, it was stated that turbulence models are not still completely reliable within the NEMO framework and that they are under development. At the moment, since I am using laminar conditions, I get lower values away from the stagnation point with respect to NASA predictions, which is expected since flow over the MSL capsule is turbulent, and hence heat flux is augmented. giovanni.medici and Tomjugj like this.

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August 21, 2023, 15:06		#2
bigfootedrockmidget Senior Member bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 676 Rep Power: 21	I see that nobody answered, I am not a nemo researcher so I only know that nemo+turbulence is in one of the feature branches and is in active development. For the other questions, you would need to ask one of the nemo developers directly, maybe in slack.