[coops]

Is it possible to take the Lagrangian derivative of a volVectorField (U) and (in a seperate equation) also a volScalar Field (T)? At the moment when I try to use these I get the following errors:

fvc::DDt(U) + ....

error: no matching function for call to 'DDt(Foam::volVectorField&)'

and for T:

fvc::DDt(T)+....

error: no matching function for call to 'DDt(Foam::volScalarField&)'

If it is not possible can anyone suggest a solution?

Thanks in advance,

Shaun

[hjasak]

Sorry for stating the obvious, but the substantial derivative requires a velocity field, right? Therefore in order to evaluate it, fvc:: (or fvm:: for that matter), needs access to the fluxes - that's why you need to arguments. Have a look at fvcDDt.H for the list of available function signatures.

Hrv