管式填充床中两相流的模拟中，循环边界压力梯度、分散相含率运算出错的问题

[Caijinjin]

最近在做管式填充床中两相流动的模拟，采用循环边界cyclicAMI达到缩短管长，减少网格的目的。网格使用snappyHexMesh画完后没有问题，动力源项给的是连续项平均速度Ubar，为0.03m/s，填充床几何为

运算时出现如下结果：

主要就是动力源计算的压力梯度一直在正负之间反复跳动，且数值非常大，压力P_rgh的迭代次数会超限。运算一段时间后会直接导致求解的相分数远远超出0-1的范围，如下图所示：

想请教一下对这种循环边界熟悉的老师同学，能够解答一下我这些问题。
另外附上我的fvSolution：

solvers
{
    "alpha.*"
    {
        nAlphaCorr      1;
        nAlphaSubCycles 3;
        implicitPhasePressure yes;
       
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-8;
        relTol          0;
        minIter         1;
    }

    p_rgh
    {
        solver          PCG;
        preconditioner  FDIC;
        tolerance       1e-6;
        relTol          0.01;
    }

    p_rghFinal
    {
        $p_rgh;
        tolerance       1e-6;
        relTol          0;
    }
    
    "U."
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-7;
        relTol          0;
        minIter         1;
    }

    "(e|h).*"
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1;
        relTol          0;
        minIter         0;
        maxIter         0;
    }

    "(k|epsilon|omega).*"
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-7;
        relTol          0;
        minIter         1;
    }
}

PIMPLE
{
    nOuterCorrectors    3;
    nCorrectors         2;
    nNonOrthogonalCorrectors 1;
    pRefPoint (0.10399 0 0);
    pRefValue 101325;
}

relaxationFactors
{
    equations
    {
        ".*"            0.7;
    }
}

fvSchemes：

ddtSchemes
{
    default         Euler;
}

gradSchemes
{
    default         Gauss linear;
    limited         cellLimited Gauss linear 1;
}

divSchemes
{
    default                         none;

    "div\(phi,alpha.*\)"            Gauss vanLeer;
    "div\(phir,alpha.*\)"           Gauss vanLeer;

    "div\(alphaRhoPhi.*,U.*\)"      Gauss linearUpwind limited;
    "div\(phi.*,U.*\)"              Gauss linearUpwind limited;

    "div\(alphaRhoPhi.*,(h|e).*\)"        Gauss linearUpwind limited;
    "div\(alphaPhi.*,f.*\)"         Gauss linearUpwind limited;
    "div\(alphaRhoPhi.*,K.*\)"      Gauss linearUpwind limited;
    "div\(alphaPhi.*,p\)"           Gauss linearUpwind limited;
    "div\(alphaRhoPhi.*,\(p\|thermo:rho.*\)\)"     Gauss linearUpwind limited;
    "div\(alphaRhoPhi.*,(k|epsilon|omega).*\)"      Gauss linearUpwind limited;

    "div\(\(\(\(alpha.*\*thermo:rho.*\)\*nuEff.*\)\*dev2\(T\(grad\(U.*\)\)\)\)\)"  Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
}

wallDist
{
    method          meshWave;
    nRequired       yes;
}

[李东岳]

你这个看起来不太好收敛。你有没有尝试单向流，压力梯度有震荡么

[Caijinjin]

@李东岳
单相流我还没尝试过，之前用过空的圆管做过一样的案例，问题都解决了。
现在我这边入口fixedValue，mapped边界条件都能是正常运行，就cyclicAMI出现问题，所以我打算先看看mapped的结果。

[李东岳]

meanVelocity这面有个phaseMeanVelocity，可用于多相流，不过不确定是否有用。

[Caijinjin]

@李东岳 好的，李老师，我去调试看看