如何获得流域中等值面的最小流向坐标？

数值仿真 OpenFOAM
1

最近在写一个燃烧流场后处理的代码，目的是要提取出以燃烧释热率（Qdot）为1E+9J/m3/s的等值面在流向（y方向）的最小坐标，将其定义为Flame lift-off，代码如图1所示。目前在OF教程中的aachenBomb案例（图2）基础上进行测试，编译成功后输出的Flame lift-off值（图3）和paraview中提取的流场数据（图2）不一致；比如在0.0004s时Flame lift-off值大概是y=0.07,但是后处理程序输出的是0.0005；而且所有时刻的Flame lift-off都是0.0005，请问大家知道怎么解决么？个人C++小白，如果需要C++语句的撰写修改，请前辈指出方向，我去学习下，非常感谢！

图片
图片1180×720 67.5 KB 

\*---------------------------------------------------------------------------*/

#include "argList.H"
#include "Time.H"
#include "timeSelector.H"
#include "fvCFD.H"
#include "transformGeometricField.H"

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

int main(int argc, char *argv[])
{
    timeSelector::addOptions();
    #include "addRegionOption.H"
    #include "setRootCase.H"
    #include "createTime.H"
    instantList timeDirs = timeSelector::select0(runTime, args);
    #include "createMesh.H"

    std::ofstream file("Flame-lifty.plt",ios_base::app); // open a file ++
    forAll(timeDirs, timeI)
    {
    runTime.setTime(timeDirs[timeI], timeI);
    Info<< "Reading field Qdot\n" << endl;

    volScalarField Qdot
    (
        IOobject
        (
            "Qdot",
            runTime.timeName(),
            mesh,
            IOobject::MUST_READ,
            IOobject::NO_WRITE
        ),
        mesh
    );

    scalar MinYlocation = 0.1;// 0.1 is the maximum y position in the domain
    label index_ = 0;

    forAll(Qdot, cellI)
    {
      
      if (Qdot[cellI] == scalar(1e9))
      
      {
        scalar y = mesh.C()[cellI].component(vector::Y);
        if (y < MinYlocation)
        {
          MinYlocation = y;
        }
      }
    }
    MinYlocation = mesh.C()[index_].component(vector::Y);

    Info << "   Time= " << runTime.value()<<"," << " flame lift_off=" << MinYlocation  << endl ;
    file << runTime.value() << " " <<MinYlocation << " " << std::endl;
         
    }    
    file.close();  //close the file ++
    return 0;
}