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Challenge

Week 12 - Symmetry vs Wedge vs HP equation

NNishaanth Ramesh20 Jan 2021
CFDMATLAB

WEDGE BOUNDARY CONDITION :

wedge boundary condition is used for the wedge angle that is less than 5. Whereas, for more than 5 wedge symmetry condition is used.

In this challenge we are supposed to run the stimulation for different angles of 10, 25, 45 and calculate the parameter each.The intial conditipon for each case of simulation are same, The main difference is that the front and the back wedge boundary condition. Here symmetry boundary condition is used and the input is recieved from the user.

MATLAB CODE :

close all 
clear all
clc

Re=2100;
rho=1000;
d=0.02;
r=d/2;
l_in=0.06*Re*d;
mu=0.00089;
nu=mu/rho;


fprintf('Enter the wedge ange fro BC 10,25,45 \n');
theta =input('enter the angle:');

v_avg=Re*nu/d;
l=l_in+0.3;
delp=(8*v_avg*mu*l)/r^2;

v0=[0 0 0];
v1=[0 r*cosd(theta/2) r*sind(theta/2)];
v2=[0 r*cosd(theta/2) -r*sind(theta/2)];
v3=[l 0 0];
v4=[l r*cosd(theta/2) r*sind(theta/2)];
v5=[l r*cosd(theta/2) -r*sind(theta/2)];

b1=200;
b2=20;
b3=1;
grading=0.2;

h1='/*--------------------------------*- C++ -*----------------------------------*\';
h2='  =========                 ';
h3='  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox';
h4='   \\    /   O peration     | Website:  https://openfoam.org';
h5='    \\  /    A nd           | Version:  8';
h6='     \\/     M anipulation  |';
h7='\*---------------------------------------------------------------------------*/';

h8='   version     2.0;'
h9='    format      ascii;'
h10='    class       dictionary;'
h11='    object      blockMeshDict;'

h12='// ************************************************************************* //';

f1=fopen('blockMeshDict2.txt','wt');

fprintf(f1,'%s\n',h1);
fprintf(f1,'%s\n',h2);
fprintf(f1,'%s\n',h3);
fprintf(f1,'%s\n',h4);
fprintf(f1,'%s\n',h5);
fprintf(f1,'%s\n',h6);
fprintf(f1,'%s\n \n',h7);

fprintf(f1,'FoamFile \n {\n ');
fprintf(f1,'%s\n',h8);
fprintf(f1,'%s\n',h9);
fprintf(f1,'%s\n',h10);
fprintf(f1,'%s\n',h11);
fprintf(f1,'%2s\n','}');

fprintf(f1,'%2s\n\n','// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //');
fprintf(f1,'%2s\n\n','convertToMeters 1;');

fprintf(f1,'vertices \n (\n ');
fprintf(f1,'\t(%d %d %d)\n',v0);
fprintf(f1,'\t(%d %d %d)\n',v1);
fprintf(f1,'\t(%d %d %d)\n',v2);
fprintf(f1,'\t(%d %d %d)\n',v3);
fprintf(f1,'\t(%d %d %d)\n',v4);
fprintf(f1,'\t(%d %d %d)\n',v5);
fprintf(f1,'%2s\n\n',');');

fprintf(f1,'blocks \n (\n ');
fprintf(f1,'\t %s (%d %d %d %d %d %d %d %d) (%d %d %d) %s (%d %d %d) \n','hex', 0, 3, 5, 2, 0, 3, 4, 1, 200, 20, 1, 'simpleGrading', 0.2, 1, 1 );
fprintf(f1,'%2s\n\n',');');

fprintf(f1,'edges \n (\n ');
fprintf(f1,'\t %s (0 %d 0)\n','arc 1 2',r);
fprintf(f1,'\t %s (%d %d 0)\n','arc 4 5',l,r);
fprintf(f1,'%2s\n\n',');');

fprintf(f1,'boundary \n (\n ');
fprintf(f1,'\t %5s \n','inlet','{');
fprintf(f1,'\t %13s %s\n','type','patch;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(0 1 2 0)',');','}');

fprintf(f1,'\t %5s \n','outlet','{');
fprintf(f1,'\t %13s %s\n','type','patch;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(3 5 4 3)',');','}');

fprintf(f1,'\t %5s \n','frontwedge','{');
fprintf(f1,'\t %13s %s\n','type','wedge;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(0 3 4 1)',');','}');

fprintf(f1,'\t %5s \n','backwedge','{');
fprintf(f1,'\t %13s %s\n','type','wedge;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(0 2 5 3)',');','}');

fprintf(f1,'\t %5s \n','wall','{');
fprintf(f1,'\t %13s %s\n','type','wall;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(1 4 5 2)',');','}');

fprintf(f1,'\t %5s \n','axis','{');
fprintf(f1,'\t %13s %s\n','type','empty;');
fprintf(f1,'\t %14s\n %18s\n','faces','(');
fprintf(f1,'\t \t %15s\n %19s\n\n %14s\n\n','(0 3 3 0)',');','}');
fprintf(f1,'%2s\n\n',');');

fprintf(f1,'mergePatchPairs \n (\n );\n');
fprintf(f1,'%2s\n\n',h12);

fclose(f1);

CONTROLDICT FILE :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     icoFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         10;

deltaT          0.01;

writeControl    timeStep;

writeInterval   20;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;


// ************************************************************************* //

TRANSPORTPROPERTIES FILE :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

nu              [0 2 -1 0 0 0 0] 0.89e-6;


// ************************************************************************* //

PRESSURE FILE :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    inlet
    {
        type            zeroGradient;
    }
    outlet
    {
        type            fixedValue;
        value           uniform 0.018;
    }

    frontwedge
    {
        type            wedge;
    }
    backwedge
    {
        type            wedge;
    }

    wall
    {
        type            zeroGradient;
    }
     axis
    {
        type            empty;
    }
}

// ************************************************************************* //

VELOCITY FILE :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform (0.09345 0 0);
    }

    outlet
    {
        type            zeroGradient;
    }

    frontwedge
    {
        type            wedge;
    }
    backwedge
    {
        type            wedge;
    }
    wall
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    axis
    {
        type            empty;
    }
}

// ************************************************************************* //

GENERATED BlockMeshDict FILE (for wedge angle 10) :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
 
FoamFile 
 {
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
 }
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices 
 (
 	(0 0 0)
	(0 0.00996195 0.000871557)
	(0 0.00996195 -0.000871557)
	(2.82 0 0)
	(2.82 0.00996195 0.000871557)
	(2.82 0.00996195 -0.000871557)
);

blocks 
 (
 	 hex (0 3 5 2 0 3 4 1) (200 20 1) simpleGrading (0.2 1 1) 
);

edges 
 (
 	 arc 1 2 (0 0.01 0)
	 arc 4 5 (2.82 0.01 0)
);

boundary 
 (
 	 inlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (0 1 2 0)
                  );

              }

	 outlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (3 5 4 3)
                  );

              }

	 frontwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 3 4 1)
                  );

              }

	 backwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 2 5 3)
                  );

              }

	  wall 
	     { 
	          type wall;
	          faces
                  (
	 	       (1 4 5 2)
                  );

              }

	  axis 
	     { 
	          type empty;
	          faces
                  (
	 	       (0 3 3 0)
                  );

              }

);

mergePatchPairs 
 (
 );
// ************************************************************************* //

BLOCKMESH FOR WEDGE 10 :

FLOW FOR WEDGE 10 :

FULLY DEVELOPED GRAPH FOR WEDGE 10 :

GENERATED BlockMeshDict FILE (for wedge angle 25) :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
 
FoamFile 
 {
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
 }
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices 
 (
 	(0 0 0)
	(0 0.00976296 0.0021644)
	(0 0.00976296 -0.0021644)
	(2.82 0 0)
	(2.82 0.00976296 0.0021644)
	(2.82 0.00976296 -0.0021644)
);

blocks 
 (
 	 hex (0 3 5 2 0 3 4 1) (200 20 1) simpleGrading (0.2 1 1) 
);

edges 
 (
 	 arc 1 2 (0 0.01 0)
	 arc 4 5 (2.82 0.01 0)
);

boundary 
 (
 	 inlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (0 1 2 0)
                  );

              }

	 outlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (3 5 4 3)
                  );

              }

	 frontwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 3 4 1)
                  );

              }

	 backwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 2 5 3)
                  );

              }

	  wall 
	     { 
	          type wall;
	          faces
                  (
	 	       (1 4 5 2)
                  );

              }

	  axis 
	     { 
	          type empty;
	          faces
                  (
	 	       (0 3 3 0)
                  );

              }

);

mergePatchPairs 
 (
 );
// ************************************************************************* //

BLOCKMESH FOR WEDGE 25 :

FLOW FOR WEDGE 25 :

FULLY DEVELOPED GRAPH FOR WEDGE 25 :

GENERATED BlockMeshDict FILE (for wedge angle 45) :

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
 
FoamFile 
 {
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
 }
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices 
 (
 	(0 0 0)
	(0 0.0092388 0.00382683)
	(0 0.0092388 -0.00382683)
	(2.82 0 0)
	(2.82 0.0092388 0.00382683)
	(2.82 0.0092388 -0.00382683)
);

blocks 
 (
 	 hex (0 3 5 2 0 3 4 1) (200 20 1) simpleGrading (0.2 1 1) 
);

edges 
 (
 	 arc 1 2 (0 0.01 0)
	 arc 4 5 (2.82 0.01 0)
);

boundary 
 (
 	 inlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (0 1 2 0)
                  );

              }

	 outlet 
	     { 
	          type patch;
	          faces
                  (
	 	       (3 5 4 3)
                  );

              }

	 frontwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 3 4 1)
                  );

              }

	 backwedge 
	     { 
	          type wedge;
	          faces
                  (
	 	       (0 2 5 3)
                  );

              }

	  wall 
	     { 
	          type wall;
	          faces
                  (
	 	       (1 4 5 2)
                  );

              }

	  axis 
	     { 
	          type empty;
	          faces
                  (
	 	       (0 3 3 0)
                  );

              }

);

mergePatchPairs 
 (
 );
// ************************************************************************* //

BLOCKMESH FOR WEDGE 45 :

FLOW FOR WEDGE 45 :

FULLY DEVELOPED GRAPH FOR WEDGE 45 :

CONCLUSION :

  • Simulation time is larger for wedge bc compared to that of symmetry bc.
  • The accuracy is more for symmetry than wedge.
  • The CFL number increases with the wedge angle increase.
execution time clock time max CFL mean CFL
wedge 10 30.57s 49s 0.3086 0.06710
wedge 25 30.67s 51s 0.3104 0.06711
wedge 45 30.98s 52s 0.3149 0.06712
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