BlogFor BusinessTalk to a counsellor
CoursesIIT ProgramsPlacementsLog in
BlogFor Business
Talk to a counsellor
Challenge

Week 12 - Validation studies of Symmetry BC vs Wedge BC in OpenFOAM vs Analytical H.P equation

RRamachandran S12 Oct 2022
CFDHTMLMATLAB

MATLAB CODE FOR CREATING BLOCKMESHDICT FILE:

clear all
close all
clc

theta=45; %wedge angle
Re =2100;%Reynold's number
D =0.01;%Diameter
R =D/2;%Radius
Le =0.05*Re*D; %hydrodynamic entry length
L =Le+0.4; %Total length

%Temperature = 25degree celsius
mu =8.90*10^-4;  %Dynamic viscosity
rho =997;  %density
nu =8.9267*10^-7; %kinematic viscosity

V_avg =(Re*mu)/(rho*D); %average velocity
V_max =2*V_avg; %maximum velocity
delta_p =(32*mu*L*V_avg)/(D^2); %pressure drop
kinematic_pressure =delta_p/rho; %kinematic pressure


%Vertices
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)];






q1 ='/*--------------------------------*- C++ -*----------------------------------*\';
q2 ='  =========                 |';
q3 ='  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox';
q4 ='   \\    /   O peration     | Website:  https://openfoam.org';
q5 ='    \\  /    A nd           | Version:  9';
q6 ='     \\/     M anipulation  |';
q7 ='\*---------------------------------------------------------------------------*/';
q8 ='FoamFile';
q9 ='{';
q10 ='    format      ascii;';
q11 ='    class       dictionary;';
q12 ='    object      blockMeshDict;';
q13 ='}';
q14 ='// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //';


%creating the blockMeshDict file

f1 = fopen('blockMeshDict','w');
fprintf(f1,'%s\n',q1);
fprintf(f1,'%s\n',q2);
fprintf(f1,'%s\n',q3);
fprintf(f1,'%s\n',q4);
fprintf(f1,'%s\n',q5);
fprintf(f1,'%s\n',q6);
fprintf(f1,'%s\n',q7);
fprintf(f1,'%s\n',q8);
fprintf(f1,'%s\n',q9);
fprintf(f1,'%s\n',q10);
fprintf(f1,'%s\n',q11);
fprintf(f1,'%s\n',q12);
fprintf(f1,'%s\n',q13);
fprintf(f1,'%s\n',q14);
fprintf(f1,'\n');

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

fprintf(f1,'%s\n','vertices');
fprintf(f1,'%s\n','(');

fprintf(f1,'\t(%f %f %f)\n',v0(1),v0(2),v0(3));
fprintf(f1,'\t(%f %f %f)\n',v1(1),v1(2),v1(3));
fprintf(f1,'\t(%f %f %f)\n',v2(1),v2(2),v2(3));
fprintf(f1,'\t(%f %f %f)\n',v3(1),v3(2),v3(3));
fprintf(f1,'\t(%f %f %f)\n',v4(1),v4(2),v4(3));
fprintf(f1,'\t(%f %f %f)\n',v5(1),v5(2),v5(3));

fprintf(f1,'%s\n',');');
fprintf(f1,'\n');

%blocks
fprintf(f1,'%s\n','blocks');
fprintf(f1,'%s\n','(');
fprintf(f1,'\t%s\n','hex (0 3 5 2 0 3 4 1) (200 50 1) simpleGrading (1 0.3 1)');
fprintf(f1,'%s\n',');');
fprintf(f1,'\n');

%edges
fprintf(f1,'%s\n','edges');
fprintf(f1,'%s\n','(');
fprintf(f1,'\t%s\n','arc 1 2 (0.000000 0.005 0.000000)');
fprintf(f1,'\t%s\n','arc 4 5 (1.450000 0.005 0.000000)');
fprintf(f1,'%s\n',');');
fprintf(f1,'\n');

%boundary
fprintf(f1,'%s\n','boundary');
fprintf(f1,'%s\n','(');
fprintf(f1,'\t%s\n','inlet');
fprintf(f1,'\t%s\n','{');
fprintf(f1,'\t\t%s\n','type patch;');
fprintf(f1,'\t\t%s\n','faces');
fprintf(f1,'\t\t%s\n','(');
fprintf(f1,'\t\t\t%s\n','(0 1 2 0)');
fprintf(f1,'\t\t%s\n',');');
fprintf(f1,'\t%s\n','}');
fprintf(f1,'\n');

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

fprintf(f1,'\t%s\n','axis');
fprintf(f1,'\t%s\n','{');
fprintf(f1,'\t\t%s\n','type empty;');
fprintf(f1,'\t\t%s\n','faces');
fprintf(f1,'\t\t%s\n','(');
fprintf(f1,'\t\t\t%s\n','(0 3 3 0)');
fprintf(f1,'\t\t%s\n',');');
fprintf(f1,'\t%s\n','}');
fprintf(f1,'\n');

fprintf(f1,'\t%s\n','front');
fprintf(f1,'\t%s\n','{');
fprintf(f1,'\t\t%s\n','type wedge;');
fprintf(f1,'\t\t%s\n','faces');
fprintf(f1,'\t\t%s\n','(');
fprintf(f1,'\t\t\t%s\n','(0 2 5 3)');
fprintf(f1,'\t\t%s\n',');');
fprintf(f1,'\t%s\n','}');
fprintf(f1,'\n');

fprintf(f1,'\t%s\n','back');
fprintf(f1,'\t%s\n','{');
fprintf(f1,'\t\t%s\n','type wedge;');
fprintf(f1,'\t\t%s\n','faces');
fprintf(f1,'\t\t%s\n','(');
fprintf(f1,'\t\t\t%s\n','(0 3 4 1)');
fprintf(f1,'\t\t%s\n',');');
fprintf(f1,'\t%s\n','}');
fprintf(f1,'\n');

fprintf(f1,'\t%s\n','top');
fprintf(f1,'\t%s\n','{');
fprintf(f1,'\t\t%s\n','type wall;');
fprintf(f1,'\t\t%s\n','faces');
fprintf(f1,'\t\t%s\n','(');
fprintf(f1,'\t\t\t%s\n','(1 2 5 4)');
fprintf(f1,'\t\t%s\n',');');
fprintf(f1,'\t%s\n','}');
fprintf(f1,'\n');

fprintf(f1,'%s\n',')');

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

BLOCKMESHDICT FILE:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
	(0.000000 0.000000 0.000000)
	(0.000000 0.004619 0.001913)
	(0.000000 0.004619 -0.001913)
	(1.450000 0.000000 0.000000)
	(1.450000 0.004619 0.001913)
	(1.450000 0.004619 -0.001913)
);

blocks
(
	hex (0 3 5 2 0 3 4 1) (200 50 1) simpleGrading (1 0.3 1)
);

edges
(
	arc 1 2 (0.000000 0.005 0.000000)
	arc 4 5 (1.450000 0.005 0.000000)
);

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

	outlet
	{
		type patch;
		faces
		(
			(3 4 5 3)
		);
	}
	
	axis
	{
		type empty;
		faces
		(
			(0 3 3 0)
		);
	}

	front
	{
		type symmetry;
		faces
		(
			(0 2 5 3)
		);
	}

	back
	{
		type symmetry;
		faces
		(
			(0 3 4 1)
		);
	}

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

)
mergePatchPairs
(
);

CONTROLDICT FILE:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     icoFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         14;

deltaT          0.001;

writeControl    timeStep;

writeInterval   20;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;


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

TRANSPORT PROPERTIES:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    location    "constant";
    object      transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

nu              [0 2 -1 0 0 0 0] 8.9267e-07;


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

VELOCITY BOUNDARY CONDITION:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    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 (0.1875 0 0);
    }

    outlet
    {
        type            zeroGradient;
    }
    
    axis
    {
        type            empty;
    }

    front
    {
        type            symmetry;
    }
    
    back
    {
        type            symmetry;
    }
    
    top
    {
        type            noSlip;
    }
    

}

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

PRESSURE BOUNDARY CONDITION:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    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;
    }
    
    axis
    {
        type            empty;
    }
    
    front
    {
        type            symmetry;
    }

    back
    {
        type            symmetry;
    }
    
    top
    {
        type            zeroGradient;
    }
    

}

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

Results

For Symmetry boundary condition

Wedge angle -10 degree

Wedge angle - 25 degree

Wedge angle - 45 degree

For Wedge boundary condition

Wedge angle - 10 degree

Wedge angle - 25 degree

Wedge angle - 45 degree

Numerical results

Vavg= 0.1875 m/s

Vmax= 0.3749m/s

τ= 0.13346 N/m^2

Conclusion

* From the results it is clear that for symmetry and wedge boundary conditions the plots are almost similar and the values are close to the analytical solution.

* The execution time is higher for symmetry boundary condition than for wedge boundary condition.

Your portfolio, next

Ship work like this
in your own course.

Talk to a career counsellor

Free 20-minute call. We'll map the right course to where you want to work.

By submitting you agree to our Terms and Privacy Policy.