CFD Online Discussion Forums - volVolumeField from volSurfaceField

Greetings !

To make a volVolumeField consisting of 3 volScalarField i tried this code? but it doesn't work.

Code:

volTensorField gradq = fvc::grad(q);



volScalarField qx = gradq.component(vector::X);

volScalarField qy = gradq.component(vector::Y);

volScalarField qz = gradq.component(vector::Z);



diaggradq.internalField() = vectorField(qx,qy,qz) ;

there q is volVectorField and diaggradq is volVectorField too.

The main goal is to make a vector (dq/dx , dq/dy , dq/dz), and I can't think how to do it without extracting diagonal elements from grad(q) tensor.

Thanks for helping, best regards.