[RamJedi]

Thanks Jon for the response

But my first attempt was to try the code as it was posted in the forum. That itself didn't work. subsequently I tried out many options none of them worked.
g=gunits*Foam::sin(runTime.value()*pi*2.0 *freq)*vector(0,0,1);
g=gunits*vector(0,0,1);
g=vector(0,0,1);
All of them give a type mismatch.

My understanding from the error message is that g is of the type gravity whereas the expression on the RH is of the type dimensioned vector. So it isn't able to assign.

In fact the full error message is as below
interFoam2.C:113:3: error: no match for âoperator=â (operand types are âconst Fo am::meshObjects::gravityâ and âFoam::dimensioned<Foam::Vector<double> >â)
g=gunits*Foam::sin(runTime.value()*pi*2.0*freq)*ve ctor(0,0,1);
^
interFoam2.C:113:3: note: candidate is:
In file included from /scratch/OpenFOAM/OpenFOAM-v1812/src/finiteVolume/lnInclud e/fvCFD.H:24:0,
from interFoam2.C:38:
/scratch/OpenFOAM/OpenFOAM-v1812/src/finiteVolume/lnInclude/gravityMeshObject.H: 53:7: note: Foam::meshObjects::gravity& Foam::meshObjects::gravity:perator=(co nst Foam::meshObjects::gravity&) <deleted>
class gravity
^
/scratch/OpenFOAM/OpenFOAM-v1812/src/finiteVolume/lnInclude/gravityMeshObject.H: 53:7: note: no known conversion for argument 1 from âFoam::dimensioned<Foam::V ector<double> >â to âconst Foam::meshObjects::gravity&â


On a different note do you have any idea on what Foam::sin() returns? I expected that it would return a double. So I had put it inside the vector definition.