[WIP] Implementation of Simplified LM Transition model #1901

rois1995 · 2023-01-27T18:26:29Z

Proposed Changes

Hi everyone! I am starting to implement the Simplified version of the Langtry-Menter transition model following the work in https://doi.org/10.2514/6.2012-672. More updates will follow.

Related Work

This follows the implementation of the LM model as #1751.

I am submitting my contribution to the develop branch.
My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
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.

rois1995 · 2023-01-27T18:28:50Z

Technically, this model has only one equation, the one for intermittency. Most of the functions are the same as the original LM model. Should I consider the Simplified model (SLM) as an option for the LM model to avoid duplicates? This is how I started, but I am open to discussions and suggestions.

pcarruscag

If the changes to the solver don't become too intrusive this approach sounds good to me

SU2_CFD/src/solvers/CTransLMSolver.cpp

- Added correlations for Simplified LM. - There is a bug on the computation of grad(n*U)*n

rois1995 · 2023-01-31T17:28:58Z

I have a question: for each point in the mesh I am trying to compute the dot product between the velocity vector and the normal to the wall of the nearest point on the wall. How do I access such information? I've found that in the CPoint class I have the ClosestWall_Elem variable which stores the index of the closest element on a wall. However, when I try to assess the information with a number of cores greater than 2, it crashes. Moreover, to recover the normal of the element I perform a mean of the normals on the nodes of that element. Is there a structure that has the normals saved for each element of the primal grid? The part that I am referring to is from line 208 in CTransLMSolver.cpp .

SU2_CFD/include/numerics/turbulent/transition/trans_correlations.hpp

+    switch (options.Correlation_SLM) {
+      case TURB_TRANS_CORRELATION_SLM::MENTER_SLM: {
+
+        /*-- Thwaites parameter ---*/
+        su2double  lambda_theta_local = 7.57e-3 * du_ds * wall_dist * wall_dist * Density / Laminar_Viscosity + 0.0128;
+        lambda_theta_local = min(max(lambda_theta_local, -1.0), 1.0);
+
+        /*-- Function to sensitize the transition onset to the streamwise pressure gradient ---*/
+        su2double FPG = 0.0;
+        const su2double C_PG1 = 14.68;
+        const su2double C_PG1_lim = 1.5;
+        const su2double C_PG2 = -7.34;
+        const su2double C_PG2_lim = 3.0;
+        const su2double C_PG3 = 0.0;
+        if (lambda_theta_local >= 0.0) {
+          FPG = min(1+ C_PG1 * lambda_theta_local, C_PG1_lim);
+        } else {
+          const su2double FirstTerm = C_PG2 * lambda_theta_local;
+          const su2double SecondTerm = C_PG3 * min(lambda_theta_local + 0.0681, 0.0);
+          FPG = min(1 + FirstTerm + SecondTerm, C_PG2_lim);
+        }
+
+        FPG = max(FPG, 0.0);
+
+        const su2double C_TU1 = 100.0;
+        const su2double C_TU2 = 1000.0;
+        const su2double C_TU3 = 1.0;
+        rethetac = C_TU1 + C_TU2 * exp(-C_TU3 * Tu_L * FPG);
+
+        break;
+      } case TURB_TRANS_CORRELATION_SLM::CODER_SLM: {
+
+        /*-- Local pressure gradient parameter ---*/
+        const su2double H_c = max(min(wall_dist * VorticityMag / VelocityMag, 1.1542), 0.3823);
+
+        /*-- Thwaites parameter ---*/
+        su2double lambda_theta_local = 0.0;
+        const su2double H_c_delta = 0.587743 - H_c;
+        if ( H_c >= 0.587743 ) {
+          const su2double FirstTerm = 0.1919 * pow(H_c_delta, 3.0);
+          const su2double SecondTerm = 0.4182 * pow(H_c_delta, 2.0);
+          const su2double ThirdTerm = 0.2959 * H_c_delta;
+          lambda_theta_local = FirstTerm + SecondTerm + ThirdTerm;
+        } else {
+          const su2double FirstTerm = 4.7596 * pow(H_c_delta, 3.0);
+          const su2double SecondTerm = -0.3837 * pow(H_c_delta, 2.0);
+          const su2double ThirdTerm = 0.3575 * H_c_delta;
+          lambda_theta_local = FirstTerm + SecondTerm + ThirdTerm;
+        }
+
+        /*-- Function to sensitize the transition onset to the streamwise pressure gradient ---*/
+        su2double FPG = 0.0;
+        if (lambda_theta_local <= 0.0) {
+          const su2double FirstTerm = -12.986 * lambda_theta_local;
+          const su2double SecondTerm = -123.66 * pow(lambda_theta_local, 2.0);
+          const su2double ThirdTerm = -405.689 * pow(lambda_theta_local, 3.0);
+          FPG = 1 - (FirstTerm + SecondTerm + ThirdTerm) * exp(-pow(Tu_L/1.5,1.5));
+        } else {
+          FPG = 1 + 0.275 * (1 - exp(-35.0 * lambda_theta_local)) * exp(-Tu_L/0.5);
+        }
+
+        // This is not reported in the paper
+        //FPG = max(FPG, 0.0);
+
+        const su2double C_TU1 = 100.0;
+        const su2double C_TU2 = 1000.0;
+        const su2double C_TU3 = 1.0;
+        rethetac = C_TU1 + C_TU2 * exp(-C_TU3 * Tu_L * FPG);
+
+        break;
+      } case TURB_TRANS_CORRELATION_SLM::MOD_EPPLER_SLM: {
+
+        /*-- Local pressure gradient parameter ---*/
+        const su2double H_c = max(min(wall_dist * VorticityMag / VelocityMag, 1.1542), 0.3823);
+
+        /*-- H_32 Shape factor --*/
+        const su2double H_32 = 1.515095 + 0.2041 * pow((1.1542 - H_c), 2.0956);
+
+        rethetac = exp(127.94 * pow((H_32-1.515095), 2.0) + 6.774224);
+
+        break;
+      }
+      case TURB_TRANS_CORRELATION_SLM::DEFAULT:
+        SU2_MPI::Error("Transition correlation for Simplified LM model is set to DEFAULT but no default value has ben set in the code.",
+                       CURRENT_FUNCTION);
+        break;
+    }


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

SU2_CFD/src/solvers/CTransLMSolver.cpp

SU2_CFD/include/numerics/turbulent/transition/trans_correlations.hpp

@@ -25,6 +25,7 @@
 */

 #pragma once
+//#include <cmath>


- Modified LM_OPTIONS to include cross-flow effects: from LM2015 to CROSSFLOW

pcarruscag · 2023-01-31T19:25:16Z

See what is done at the bottom of CGeometry.cpp in CGeometry::ComputeWallDistance.
You need to communicate the normals you need first.

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CodeQL found more than 10 potential problems in the proposed changes. Check the Files changed tab for more details.

WallyMaier · 2023-02-01T05:47:54Z

Common/include/geometry/dual_grid/CPoint.hpp

+   * \brief Get the index of the closest wall element.
+   * \param[in] iPoint - Index of the point.
+   */
+  inline unsigned long GetClosestWall_Elem(unsigned long iPoint) {return ClosestWall_Elem(iPoint);}


Can you add the param[out] for these please

Sure, I'll do it now.

WallyMaier · 2023-02-01T05:50:10Z

Common/include/option_structure.hpp


  if (NFoundCorrelations > 1) {
    SU2_MPI::Error("Two correlations selected for LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);
  }
+  if (NFoundCorrelations_SLM > 1) {
+    SU2_MPI::Error("Two correlations selected for Simplified model into LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);


Suggested change

SU2_MPI::Error("Two correlations selected for Simplified model into LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);

SU2_MPI::Error("Two correlations selected for simplified LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);

I'd stick with my change since the options are for the simplified model. They are not simplified options.

WallyMaier · 2023-02-01T05:50:50Z

Common/src/CConfig.cpp

@@ -3471,9 +3471,9 @@ void CConfig::SetPostprocessing(SU2_COMPONENT val_software, unsigned short val_i
  if (Kind_Trans_Model == TURB_TRANS_MODEL::LM) {
    lmParsedOptions = ParseLMOptions(LM_Options, nLM_Options, rank, Kind_Turb_Model);

-    /*--- Check if problem is 2D and LM2015 has been selected ---*/
-    if (lmParsedOptions.LM2015 && val_nDim == 2) {
-      SU2_MPI::Error("LM2015 is available only for 3D problems", CURRENT_FUNCTION);


is LM2015 gone? or is crossflow the same?

I have changed the option to CROSSFLOW, since I will use it also for the Simplified model.

WallyMaier · 2023-02-01T05:54:18Z

SU2_CFD/include/numerics/turbulent/transition/trans_correlations.hpp

+        // This is not reported in the paper
+        //FPG = max(FPG, 0.0);
+


Suggested change

// This is not reported in the paper

//FPG = max(FPG, 0.0);

I have left it there since I do not know if I have to keep it or not.

bigfooted · 2023-02-10T16:02:42Z

I have a question: for each point in the mesh I am trying to compute the dot product between the velocity vector and the normal to the wall of the nearest point on the wall. How do I access such information? I've found that in the CPoint class I have the ClosestWall_Elem variable which stores the index of the closest element on a wall. However, when I try to assess the information with a number of cores greater than 2, it crashes. Moreover, to recover the normal of the element I perform a mean of the normals on the nodes of that element. Is there a structure that has the normals saved for each element of the primal grid? The part that I am referring to is from line 208 in CTransLMSolver.cpp .

There is the geometry toolbox for dot product and normal:
https://github.com/su2code/SU2/blob/master/Common/include/toolboxes/geometry_toolbox.hpp
just look in the code for examples, in vscode you can search for GeometryToolbox::DotProduct or GeometryToolbox::Norm

rois1995 · 2023-02-14T11:50:53Z

I have a question: for each point in the mesh I am trying to compute the dot product between the velocity vector and the normal to the wall of the nearest point on the wall. How do I access such information? I've found that in the CPoint class I have the ClosestWall_Elem variable which stores the index of the closest element on a wall. However, when I try to assess the information with a number of cores greater than 2, it crashes. Moreover, to recover the normal of the element I perform a mean of the normals on the nodes of that element. Is there a structure that has the normals saved for each element of the primal grid? The part that I am referring to is from line 208 in CTransLMSolver.cpp .

There is the geometry toolbox for dot product and normal: https://github.com/su2code/SU2/blob/master/Common/include/toolboxes/geometry_toolbox.hpp just look in the code for examples, in vscode you can search for GeometryToolbox::DotProduct or GeometryToolbox::Norm

The problem is more related to the finding of the wall-normal for a point within the volume mesh, not to the computations that it will be involved in.

pcarruscag · 2023-02-14T15:05:26Z

The solution I suggested didn’t work?

rois1995 · 2023-02-14T15:46:22Z

The solution I suggested didn’t work?

I still have to check if the implementation is correct but with more than two cores the code breaks. However, I found out that the wall-normal of a volume point can be computed as the normalized gradient of the wall-distance. Does this sound correct to you?

However, there is a problem: I am using the aux variables to compute these gradients, but to compute dot(n, U) I first need n, thus I cannot compute them simultaneously. Since these computations are performed in the Preprocessing of the solvers, I was thinking to compute the normal within the FLOW_SOL preprocessing and the dot(n, U) in the TRANS_SOL preprocessing since the flow solver comes before the trans solver. Is this right?

pcarruscag · 2023-02-14T16:09:19Z

It's not correct. You need to follow the pattern from CGeometry::ComputeWallDistance
First you collect all the normals that are local to the rank
Then you collect the normals across all ranks (using the NDFlatner), then you access this information by (ClosestRank, ClosestMarker, ClosestVertex)
You cannot access the local information directly because ClosestMarker and ClosestVertex may refer to a different rank.

- Added variables only for debug

rois1995 · 2023-02-24T13:15:26Z

I managed to implement the computation of grad(n*U)*n, but at the moment it is located into CTransLMSolver::PreProcessing. It seems to work with a structured mesh on a flat plate. Currently, I am testing with a 2D profile too. However, being into the PreProcessing of the transition solver, the normals are computed at each iteration, thus it is not computationally efficient if non-deforming meshes are used. I am looking into where to put it such that it is computed just if the mesh is updated (and at the first iteration of course).

Plus, I have added a whole lot of variables to the output, but they will be removed in the final version. They are just used as debug.

pcarruscag · 2023-02-24T15:11:00Z

Do what we do with wall roughness and do it in the same place (computewalldistance and store in CPoint)

rois1995 · 2023-02-24T18:28:36Z

Ok, I think I managed to add it to the ComputeWallDistance function. I tested it on a 2D cylinder and it works just fine. However, when I use it on a profile with a sharp trailing edge it gives me strange results on the region behind the TE.

Cylinder:

Profile:

I guess it is intrinsic within the computation of the wall distances.

pcarruscag · 2023-02-24T18:57:40Z

My guess is that the closest element for those regions is somewhere on the trailing edge and the normals there change very quickly.

rois1995 · 2023-02-27T08:30:26Z

Yeah, I do not think that it is solvable. Plus, I do not think that it will affect the solution either.

pcarruscag · 2023-08-07T00:47:32Z

Any updates @rois1995? Is this almost ready?

rois1995 · 2024-06-28T14:09:23Z

I am sorry for leaving this hanging. I am currently back on working on it.

These are the results on the Eppler E367 case with the new SLM model implemented and with three different correlation functions.

Using the L2Roe scheme

Using the Roe scheme

I will update the branch to the last develop commit and proceed from there.

EDIT: I think this one is too far behind with respect to the develop. Should I create another branch, make the changes there and then remove this one?

bigfooted · 2024-06-28T18:10:42Z

@rois1995 I'd just merge it with develop and have a look at the conflicts in vscode. It's probably just some lines that have moved around.

rois1995 · 2024-06-28T18:13:43Z

The problem is that I am behind more than 1100 commits. I have already created another branch starting from the current develop and I am running the test cases from the paper in the description. I may be able to merge the new branch into this one and then I'll be on par with the develop, right?

…re_Trans_SLM (update this branch with develop)

Common/src/geometry/CGeometry.cpp

+        if (config->GetViscous_Wall(iMarker)) {
+          WallNormal_container[iZone][iMarker].resize(geometry->GetnElem_Bound(iMarker), 3);
+
+          // cout << "geometry->nVertex[iMarker] = " << geometry->nVertex[iMarker] << endl;


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

+    if (dist_i > 1e-10) {
+      su2double Tu_L = 1.0;
+      if (TurbFamily == TURB_FAMILY::KW) Tu_L = min(100.0 * sqrt(2.0 * ScalarVar_i[0] / 3.0) / (ScalarVar_i[1]*dist_i), 100.0);
+      // if (TurbFamily == TURB_FAMILY::KW) Tu_L = min(100.0 * sqrt(2.0 * ScalarVar_i[0] / 3.0) / (Velocity_Mag), 100.0);


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

+      //   for (int j = 0; j < nDim; j++)
+      //     du_ds = du_ds + Velocity[i]*Velocity[j]*PrimVar_Grad_i[i][j];
+
+      // du_ds = du_ds/(Velocity_Mag*Velocity_Mag);


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

+
+      // du_ds = du_ds/(Velocity_Mag*Velocity_Mag);
+
+      // const su2double lambda_theta = -7.57e-3 * du_ds * dist_i * dist_i * Density_i / Laminar_Viscosity_i + 0.0128;


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

+      // const su2double lambda_theta = du_ds * dist_i * dist_i * Density_i / Laminar_Viscosity_i;
+      // duds_Here = du_ds;


SU2_CFD/include/numerics/turbulent/transition/trans_sources.hpp

+      duds_Here = AuxVar;
+      lambda_theta_Here = lambda_theta;
+
+      // const su2double lambda_theta = 7.57e-3 * AuxVar * dist_i * dist_i * Density_i / Laminar_Viscosity_i + 0.0128;


SU2_CFD/src/solvers/CTransLMSolver.cpp

+      // cout << Re_t << " " << Corr_Rec << endl; 
+      // if (geometry->nodes->GetDomain(iPoint)) cout << "Point is on boundary" << endl;


SU2_CFD/src/solvers/CTransLMSolver.cpp

+      if(TurbFamily == TURB_FAMILY::SA)
+        f_wake = 1.0;
+
+      //cout << "StrainMag = " << StrainMag << " rho = " << rho << " dist = " << dist << " Re_v = " << Re_v << " Corr_Rec = " << Corr_Rec << endl; 


SU2_CFD/src/solvers/CTransLMSolver.cpp

+      const su2double var2 = 1.0 - pow(var1,2.0);
+      const su2double f_theta = min(max(f_wake*exp(-pow(dist/delta, 4)), var2), 1.0);
+      su2double Intermittency_Sep = 2.0*max(0.0, Re_v/(3.235*Corr_Rec)-1.0)*f_reattach;
+      //if (Intermittency_Sep>1.0) cout << "StrainMag = " << StrainMag << " rho = " << rho << " dist = " << dist << " Re_v = " << Re_v << " Corr_Rec = " << Corr_Rec <<  " Intermittency: " << Intermittency_Sep << " f_reattach = " << f_reattach << endl;


rois1995 added 3 commits January 27, 2023 18:21

- Just copied the CTransLMSolver header and source to commit

a7136d3

- Start of implementation of Simplified LM transition model

e9226db

- Modify number of variables if SLM option is used

d03742a

pr-triage bot added the PR: unreviewed label Jan 27, 2023

pcarruscag changed the title ~~Implementation of Simplified LM Transition model [WIP]~~ [WIP] Implementation of Simplified LM Transition model Jan 27, 2023

pr-triage bot removed the PR: unreviewed label Jan 27, 2023

pcarruscag reviewed Jan 27, 2023

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SU2_CFD/src/solvers/CTransLMSolver.cpp Fixed Show fixed Hide fixed

- Updates on the transition model.

e17872d

- Added correlations for Simplified LM. - There is a bug on the computation of grad(n*U)*n

github-advanced-security bot found potential problems Jan 31, 2023

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- Added Cross flow effects for SLM

4b9c615

- Modified LM_OPTIONS to include cross-flow effects: from LM2015 to CROSSFLOW

github-advanced-security bot found potential problems Jan 31, 2023

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WallyMaier reviewed Feb 1, 2023

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- Fixed Intermittency_Sep computation for SLM.

04cd56d

- Added computation for normals of grid points

e29b4df

- Added variables only for debug

Fixed normal extraction from structure

0319d62

Added computation of wall normals to the CPoint structure

b1edf61

rois1995 added 8 commits April 27, 2023 10:06

Check For changes

7eee4ab

Removing changes for SA-R

c461518

Fixed vertex indexing for wall normal computation

e68a9e4

Removed a cout

bcdd671

Fixed division by zero with Corr_Rec

9bb2435

Removed cout

a9a6ce4

Fixed Max Velocity-Z output for Incompressible flow

86b068c

Fixed output of Normals in volume

73c0a4b

rois1995 added 5 commits July 1, 2024 10:55

- Added Simplified Langtry Menter model

8d5148e

- corrected bu in output

9db7301

Merge branch 'develop' into feature_Trans_SLM_v8

1e7e7a3

Merge remote-tracking branch 'origin/feature_Trans_SLM_v8' into featu…

ab2d71b

…re_Trans_SLM (update this branch with develop)

- finish update

a6fe9bc

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[WIP] Implementation of Simplified LM Transition model #1901

[WIP] Implementation of Simplified LM Transition model #1901

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	SU2_MPI::Error("Two correlations selected for Simplified model into LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);
	SU2_MPI::Error("Two correlations selected for simplified LM_OPTIONS. Please choose only one.", CURRENT_FUNCTION);


		// du_ds = du_ds/(Velocity_Mag*Velocity_Mag);

		// const su2double lambda_theta = -7.57e-3 * du_ds * dist_i * dist_i * Density_i / Laminar_Viscosity_i + 0.0128;

		// const su2double lambda_theta = du_ds * dist_i * dist_i * Density_i / Laminar_Viscosity_i;
		// duds_Here = du_ds;

		// cout << Re_t << " " << Corr_Rec << endl;
		// if (geometry->nodes->GetDomain(iPoint)) cout << "Point is on boundary" << endl;

[WIP] Implementation of Simplified LM Transition model #1901

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