[haolee0928]

Dear Openfoam ponieers

I am simulating a compressible mixing layer by means of Openfoam. My flow domain is very simple, just a rectangular. My inlet profile is tanh shape which defines a upper flow and lower flow with different velocity : 0.5*(U_1+U_2)+0.5*(U_1-U_2)*tanh(2*y/thick).

I used codeStream to do this. Now I have a trouble as following:


To promote the mixing layer instability, I add the white noise actuation in the v component of the velocity. But it won't changed every time step. the data is always the same in every time step. This has been confirmed after I extracted inlet profile of every time step.



Could you help me about this?


The next step, i will build a closed-loop in the Openfoam: the inlet v component velocity will be an actuation of the mixing layer and it is determined by an equation. The input of this equation is the velocities of a few points in the flow domain in the last time step.

Besides, there are 50 cases with 50 different equations. That means the equations should be read into the case from external files not be modified manually. Could you help me with a roadmap?



Here are my code for the inlet profile:

I tried two methods but both cannot work.

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

internalField uniform (0 0 0);

boundaryField
{
IN
{
type fixedValue;
value #codeStream
{
codeInclude
#{
#include "fvCFD.H"
#include <random> /*generate the random number*/
#include <ctime> /* get the system number */
#include <iostream> /*Input and output*/
#};

codeOptions
#{
-I$(LIB_SRC)/finiteVolume/lnInclude \
-I$(LIB_SRC)/meshTools/lnInclude \
-std=c++11
/* EXE_INC= "-std=c++11 -03"*/
/* -I...... \ */
/* $(CPP_DEP)\ */
/* EXE_INC='-std=gnu++11'*/
/* MAKE_CXX_FLAGS "-std=c++11 -03"*/
/* EXE_INC=\
'-std=c++11'*/
#};

//libs needed to visualize BC in paraview
codeLibs
#{
-lmeshTools \
-lfiniteVolume
#};

code
#{
const IOdictionary& d = static_cast<const IOdictionary&>
(
dict.parent().parent()
);
const fvMesh& mesh = refCast<const fvMesh>(d.db());
const label id = mesh.boundary().findPatchID("IN");
const fvPatch& patch = mesh.boundary()[id];
//vectorField U(mesh.boundary()[id].size(), vector(0, 0, 0));
vectorField U(patch.size(), vector(0, 0, 0));


/* const scalar pi = constant::mathematical:i;*/
const scalar U_1 = 1151.6; //the upper velocity
const scalar U_2 = 669.1; // the lower velocity
const scalar thick = 0.198; //vorticity thickness unit mm
/* const Random randObj(time(NULL));*/
/* const scalar Uy = randobj.scalar01()*10*/
/* const scalar p_r = 8. */ //patch radius*/
cout << "add white noise";
std::default_random_engine e(time(0));
std::uniform_real_distribution<double> u(-10.0,10.0);
/* generate the white noise */
/* end the white noise */
forAll(U, i)
{
const scalar y = patch.Cf()[i][1];
//U[i] = vector(U_0*sin(pi*y/r), 0., 0.);
U[i] = vector(0.5*(U_1+U_2)+0.5*(U_1-U_2)*tanh(2*y/thick), u(e), 0.);
}
for(int i = 0; i < 1000;++i)
cout << u(e) <<endl;
/*return 0;*/
/*
for (int i; i<patch.size() ; i++)
{
const scalar y = patch.Cf()[i][1];
U[i] = vector(U_0*(1-(pow(y - p_ctr,2))/(p_r*p_r)), 0., 0.);
}
*/
U.writeEntry("", os);
#};
};
}







IN
{
type fixedValue;
value #codeStream
{
codeInclude
#{
#include "fvCFD.H"
#include "Random.H"
#include "clock.H"
#include <iostream> /*Input and output*/
#};

codeOptions
#{
-I$(LIB_SRC)/finiteVolume/lnInclude \
-I$(LIB_SRC)/meshTools/lnInclude \
/* EXE_INC= "-std=c++11 -03"*/
/* -I...... \ */
/* $(CPP_DEP)\ */
/* EXE_INC='-std=gnu++11'*/
/* MAKE_CXX_FLAGS "-std=c++11 -03"*/
/* EXE_INC=\
'-std=c++11'*/
#};

//libs needed to visualize BC in paraview
codeLibs
#{
-lmeshTools \
-lfiniteVolume
#};

code
#{
const IOdictionary& d = static_cast<const IOdictionary&>
(
dict.parent().parent()
);
const fvMesh& mesh = refCast<const fvMesh>(d.db());
const label id = mesh.boundary().findPatchID("IN");
const fvPatch& patch = mesh.boundary()[id];
//vectorField U(mesh.boundary()[id].size(), vector(0, 0, 0));
vectorField U(patch.size(), vector(0, 0, 0));


/* const scalar pi = constant::mathematical:i;*/
const scalar U_1 = 1151.6; //the upper velocity
const scalar U_2 = 669.1; // the lower velocity
const scalar thick = 0.198; //vorticity thickness unit mm
/* const Random randObj(time(NULL));*/
/* const scalar Uy = randobj.scalar01()*10*/
/* const scalar p_r = 8. */ //patch radius*/
cout << "add white noise";
/* generate the white noise */
/* end the white noise */
Random ranGen( clock::getTime() + pid());
scalar v = ranGen.integer(1,100);
forAll(U, i)
{
const scalar y = patch.Cf()[i][1];
//U[i] = vector(U_0*sin(pi*y/r), 0., 0.);
U[i] = vector(0.5*(U_1+U_2)+0.5*(U_1-U_2)*tanh(2*y/thick), v, 0.);
}
/* for(int i = 0; i < 1000;++i)
cout << ranGen.integer(1,100) <<endl;
return 0;*/
/*
for (int i; i<patch.size() ; i++)
{
const scalar y = patch.Cf()[i][1];
U[i] = vector(U_0*(1-(pow(y - p_ctr,2))/(p_r*p_r)), 0., 0.);
}
*/
U.writeEntry("", os);
#};
};
}

[haolee0928]

Thanks a lot everyone. I have finished it and coded the boundary by codedFixedValue.


It can work well.