AD Neumann BC for a vector variable

[ABallisat]

Hello all,

I have a need to set a Neumann BC for a vector variable, specifically setting a component of the gradient of a component of a vector to be a value (probably zero), for example something along the lines of

partial v_x / partial y = 0

for vector v with components x and y (and naturally extend to 3D). I am using AD so would prefer it to be within that system. I have been looking at the ADIntegratedBC.C as a basis for this but cannot figure out how to get it to work with vector variables. Could someone point me in the right direction?

I have looked at VectorNeumannBC.C but cannot figure out how it iterates over a vector variable, my understanding in this area is lacking. My guess is that the

for (_i = 0; _i < _test.size(); _i++)

line iterates over the components as _test.size() returns the number of components of the vector, is this understanding correct? If so, then i could be passed through to work out what component you are on.

Thanks for the help!

Alex

[GiudGiud]

Hi Alex

VectorNeumannBC are definitely a good start to create an AD version of that BC.
_i will indeed be the component the BC is currently considering.

You may want to look at ADVectorDirichletBC as well btw.

Guillaume