Add in Sutherland's law for NEMO problems#1702

WallyMaier · 2022-07-07T15:36:01Z

Proposed Changes

Here I am adding Sutherland's law for viscosity and thermal conductivity for NEMO problems using the native library. Experiments for these types of problems often are run using very low temperatures (~65K). Our current models aren't suited well for these temperature ranges.

There is also some general clean up work in the still-not-working Gupta-Yos model and viscous numerics.

PR Checklist

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I am submitting my contribution to the develop branch.
[X ] My contribution generates no new compiler warnings (try with the '-Wall -Wextra -Wno-unused-parameter -Wno-empty-body' compiler flags, or simply --warnlevel=2 when using meson).
My contribution is commented and consistent with SU2 style.
I have added a test case that demonstrates my contribution, if necessary.
I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp) , if necessary.

…functions

SU2_CFD/src/fluid/CSU2TCLib.cpp

WallyMaier · 2022-07-07T15:39:04Z

SU2_CFD/src/fluid/CSU2TCLib.cpp

  if(Kind_TransCoeffModel == TRANSCOEFFMODEL::GUPTAYOS)
   DiffusionCoeffGY();
+  if(Kind_TransCoeffModel == TRANSCOEFFMODEL::SUTHERLAND)
+   DiffusionCoeffWBE();


The diffusion coefficient used in the Sutherland model is still computed using the WBE routine

WallyMaier · 2022-07-07T15:39:46Z

SU2_CFD/src/fluid/CSU2TCLib.cpp


    /*--- Translational contribution to thermal conductivity ---*/
-    ThermalCond_tr    += (15.0/4.0)*kb*gam_i/denom_t;
+    if (denom_t != 0) ThermalCond_tr += (15.0/4.0)*kb*gam_i/denom_t;


This is general cleanup. The code doesn't behave just yet.....though this is a problem for another day.

This is a bit ugly. Is denom always positive? If so the standard way of protecting against division by zero is using fmax(x, EPS)

Yes denom should always be positive. I think the issue is if demon= 0 then ThermalCond_tr += 0 .
But I agree this is ugly.

Still, equality comparisons of floating point numbers with 0 are generally a bad idea, because things will also blow up with 1e-100, checking for > EPS should be safer.

Gotcha. Is there a cleaner/efficient way to make sure that if denom_t = 0, then there is no contribution to thermal conductivity? fmax(x, EPS)

I changed these around to maybe be less ugly.

SU2_CFD/include/fluid/CSU2TCLib.hpp

Common/src/CConfig.cpp

SU2_CFD/include/fluid/CSU2TCLib.hpp

pcarruscag · 2022-07-07T16:45:43Z

SU2_CFD/src/fluid/CSU2TCLib.cpp


    /*--- Translational contribution to thermal conductivity ---*/
-    ThermalCond_tr    += (15.0/4.0)*kb*gam_i/denom_t;
+    if (denom_t != 0) ThermalCond_tr += (15.0/4.0)*kb*gam_i/denom_t;


This is a bit ugly. Is denom always positive? If so the standard way of protecting against division by zero is using fmax(x, EPS)

SU2_CFD/src/fluid/CSU2TCLib.cpp

pcarruscag · 2022-07-07T16:50:27Z

SU2_CFD/src/numerics/NEMO/CNEMONumerics.cpp

+  const su2double rho = val_primvar[RHO_INDEX];
+  const su2double T = val_primvar[T_INDEX];


…to feature_NEMO_suth

jtneedels · 2022-07-11T04:02:54Z

SU2_CFD/src/fluid/CSU2TCLib.cpp

    ElDegeneracy(0,6) = 15;

+    if (viscous) {
+      mu_ref[0] = 2.125E-5;


Worth adding a comment with a reference for these values?

Good point. I can add a quick reference.

jtneedels · 2022-07-11T04:08:15Z

Common/src/CConfig.cpp

-  if (Kind_FluidModel == SU2_NONEQ && Kind_TransCoeffModel != TRANSCOEFFMODEL::WILKE ) {
-    SU2_MPI::Error("Only WILKE transport model is stable for the NEMO solver using SU2TClib. Use Mutation++ instead.", CURRENT_FUNCTION);
+  if (Kind_FluidModel == SU2_NONEQ && (Kind_TransCoeffModel != TRANSCOEFFMODEL::WILKE && Kind_TransCoeffModel != TRANSCOEFFMODEL::SUTHERLAND) ) {
+    SU2_MPI::Error("Only WILKE and SUTHERLAND transport models are stable for the NEMO solver using SU2TClib. Use Mutation++ instead.", CURRENT_FUNCTION);


How hard would it be to add this routine so it is supported by MPP?

Also, just to confirm, Sutherland is just used for viscosity then WBE is used for diffusion coeffs and thermal conductivity?

Great question. I don't know if MPP has sutherland's law, but if it does....it should be fairly simple to implement.
I guess with that thought, the Sutherlands law would be the identical implementation, but it would need additional errors if someone tried to used not AR, N2, or Air5/7.

Yes, Sutherland is used for viscosity and thermal conductivity. Blottner part of WBE is still used for diffusion coefficients.

jtneedels · 2022-07-11T04:10:59Z

config_template.cfg

 % -------------------- NEMO NUMERICAL METHOD DEFINITION -----------------------%
 %
-% Mixture transport properties (WILKE,GUPTA-YOS,CHAPMANN-ENSKOG)
+% Mixture transport properties (WILKE,GUPTA-YOS,CHAPMANN-ENSKOG, SUTHERLAND)


Overall looks good! I think this will be a good addition for running the lower temperature experimental verification cases with NEMO, where the T_{\inf} is low but he Ma_{\inf} is high.

SU2_CFD/src/fluid/CSU2TCLib.cpp

Add in Sutherland's law for NEMO problems + some clean up to viscous …

3205992

…functions

pr-triage bot added the PR: unreviewed label Jul 7, 2022

WallyMaier commented Jul 7, 2022

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WallyMaier commented Jul 7, 2022

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WallyMaier requested a review from jtneedels July 7, 2022 15:59

WallyMaier added the changelog:feature label Jul 7, 2022

pcarruscag approved these changes Jul 7, 2022

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Merge branch 'develop' into feature_NEMO_suth

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pr-triage bot added the PR: unreviewed label Jul 10, 2022

WallyMaier added 2 commits July 10, 2022 12:26

PR comments

6c3eff1

Merge branch 'feature_NEMO_suth' of https://github.com/su2code/SU2 in…

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…to feature_NEMO_suth

jtneedels approved these changes Jul 11, 2022

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Merge branch 'develop' into feature_NEMO_suth

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Merge branch 'develop' into feature_NEMO_suth

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WallyMaier commented Jul 15, 2022

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WallyMaier merged commit f2add99 into develop Jul 15, 2022

WallyMaier deleted the feature_NEMO_suth branch July 15, 2022 16:46

pr-triage bot removed the PR: unreviewed label Jul 15, 2022

pr-triage bot added the PR: merged label Jul 15, 2022

		const su2double rho = val_primvar[RHO_INDEX];
		const su2double T = val_primvar[T_INDEX];

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WallyMaier commented Jul 7, 2022

Proposed Changes

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