@李东岳 感谢李老师的解答！老师，我用的也是openfoam8，截取代码的时候没全截取给您带来误解了，抱歉。我是将代码添加在了writePositions()函数的最前面，如下：
void Foam::functionObjects::movingInterfaceHeight::writePositions()
{
scalar time = time_.value();
locations_[0][0] = 0.5 + 0.001*sin(5.3*time); locations_[0][1] = 0; locations_[0][2] = 0.5;
const uniformDimensionedVectorField& g =
mesh_.lookupObject<uniformDimensionedVectorField>("g");
const vector gHat = g.value()/mag(g.value());
const volScalarField& alpha =
mesh_.lookupObject<volScalarField>(alphaName_);
autoPtr<interpolation<scalar>>
interpolator
(
interpolation<scalar>::New(interpolationScheme_, alpha)
);
writePositions()函数下，最前面的两行即为添加的代码，后来我将整个interfaceHeight工具的代码复制了重新构建了一个“movingInterfaceHeight”工具，重新编译后问题解决了。
按照老师您说的，将其添加在const point p = locations_[li] - gHat*hIL的定义中存在一定的问题：
// Position of the interface
const point p = locations_[li] - gHat*hIL;
其中的locations_[li]为三维坐标点，point p = locations_[li] - gHat*hIL对xyz坐标均进行了计算，按照我的简谐运动规律$\lambda=0.001sin(5.0498t)$，仅x坐标发生改变，y与z应在坐标不变的情况下完成```point p``的计算，是否可以修改成以下代码：
// Position of the interface
const point p = locations_[li]; //首先定义一个point p
scalar time = time_.value();
//分别对p的xyz坐标进行计算
p.x() = 0.5 + 0.001*sin(5.0498*time) - gHat*hIL;
p.y() = 0 - gHat*hIL;
p.z() = 0.5 - gHat*hIL;
感谢李老师指导！
