SprayFoam中关于breakup model的 child parcel的速度设置问题

[星星星星晴]

各位大佬，

关于sprayFoam中的breakup model，中childparcel是如何设定其速度的？

template<class CloudType>
bool Foam::ReitzKHRT<CloudType>::update
(
    const scalar dt,
    const vector& g,
    scalar& d,
    scalar& tc,
    scalar& ms,
    scalar& nParticle,
    scalar& KHindex,
    scalar& y,
    scalar& yDot,
    const scalar d0,
    const scalar rho,
    const scalar mu,
    const scalar sigma,
    const vector& U,
    const scalar rhoc,
    const scalar muc,
    const vector& Urel,
    const scalar Urmag,
    const scalar tMom,
    scalar& dChild,
    scalar& massChild
)
{
 .......
    return addParcel;
}

上部分code节选与KHRTmodel，其中的return 的addParcel是一个boolean，true时即增加child parcel。 child parcel的mass和diameter都计算得到。

接下来进入sprayParcel.C 的calcBreakup中

 typedef typename TrackData::cloudType cloudType;
    typedef typename cloudType::parcelType parcelType;
    typedef typename cloudType::forceType forceType;

    const parcelType& p = static_cast<const parcelType&>(*this);
    const forceType& forces = td.cloud().forces();

    if (td.cloud().breakup().solveOscillationEq())
    {
        solveTABEq(td, dt);
    }

    // Average molecular weight of carrier mix - assumes perfect gas
    scalar Wc = this->rhoc()*RR*this->Tc()/this->pc();
    scalar R = RR/Wc;
    scalar Tav = td.cloud().atomization().Taverage(this->T(), this->Tc());

    // Calculate average gas density based on average temperature
    scalar rhoAv = this->pc()/(R*Tav);
    scalar muAv = this->muc();
    vector Urel = this->U() - this->Uc();
    scalar Urmag = mag(Urel);
    scalar Re = this->Re(this->U(), this->d(), rhoAv, muAv);

    const scalar mass = p.mass();
    const forceSuSp Fcp = forces.calcCoupled(p, dt, mass, Re, muAv);
    const forceSuSp Fncp = forces.calcNonCoupled(p, dt, mass, Re, muAv);
    this->tMom() = mass/(Fcp.Sp() + Fncp.Sp());

    const vector g = td.cloud().g().value();

    scalar parcelMassChild = 0.0;
    scalar dChild = 0.0;
    if
    (
        td.cloud().breakup().update
        (
            dt,
            g,
            this->d(),
            this->tc(),
            this->ms(),
            this->nParticle(),
            this->KHindex(),
            this->y(),
            this->yDot(),
            this->d0(),
            this->rho(),
            mu_,
            sigma_,
            this->U(),
            rhoAv,
            muAv,
            Urel,
            Urmag,
            this->tMom(),
            dChild,
            parcelMassChild
        )
    )
    {
        scalar Re = rhoAv*Urmag*dChild/muAv;

        // Add child parcel as copy of parent
        SprayParcel<ParcelType>* child = new SprayParcel<ParcelType>(*this);
        child->origId() = this->getNewParticleID();
        child->d() = dChild;
        child->d0() = dChild;
        const scalar massChild = child->mass();
        child->mass0() = massChild;
        child->nParticle() = parcelMassChild/massChild;

        const forceSuSp Fcp =
            forces.calcCoupled(*child, dt, massChild, Re, muAv);
        const forceSuSp Fncp =
            forces.calcNonCoupled(*child, dt, massChild, Re, muAv);

        child->age() = 0.0;
        child->liquidCore() = 0.0;
        child->KHindex() = 1.0;
        child->y() = td.cloud().breakup().y0();
        child->yDot() = td.cloud().breakup().yDot0();
        child->tc() = 0.0;
        child->ms() = -GREAT;
        child->injector() = this->injector();
        child->tMom() = massChild/(Fcp.Sp() + Fncp.Sp());
        child->user() = 0.0;
        child->setCellValues(td, dt, celli);

        td.cloud().addParticle(child);
    }

这部分Child 就包含了各个参数，且，然后在进入/basic/Cloud.C中添加进domain。
但是问题是，很多参数都是直接由parents parcel复制而来。

那么问题来了，
Q1 如果我想单独设置child parcel的速度，如何设置呢?
Q2 如果想射如多个parcel，且每个parcel有不同的size和mass如何处理呢？

[李东岳]

我想从破碎的角度来讲，单纯的破碎并没有改变气泡速度（不想碰撞），如果你想设置子粒子的速度，或许需要类似硬球模型那种模型保证动量守恒啊各种之类

[星星星星晴]

我继续看看，因为是这样，一个parent parcel breakup，他应该生成多个小液滴，但是模型里面并没有考虑数目的情况，另外一点是这样，childparcel的速度是直接从parent parcel复制过来的，

$m_{p0}\vec{v_0}=m_{prest}\vec{v_0}+\sum m_{psat}\vec{v}$

[星星星星晴]

怎么没法写公式了 = = 是不是方法用错了

质量守恒很简单，但是根据code，child的速度和数量就没办法设置。。。

我再看看哪有方法解决吧