Could somebody explain to me,
 

Could somebody explain to me, how I can implement a fixedGradient boundary condition looking like this:

d(u(i+1))/dn = f(u(i)) with time index i.

In words: I'd like to get the value of the normal derivation of u(i+1) from a function f depending on u(i), but as far as I've found out till now, fixedGradient sets the gradient to a constant value. Is it possible to replace the constant value by a function calculated during the iteration process? And if yes, could somebody give me a hint or an example how I could do this?

Many thanks in advance!!!

Hello Stefan, It is possibl
 

Hello Stefan,

It is possible the gradient to a value that is calculated during the iteration process. Have you had a look at the fixedFluxBuoyantPressure boundary condition.
(/home/you/OpenFOAM/OpenFOAM-1.4/src/finiteVolume/fields/fvPatchFields/derivedFv PatchFields/fixedFluxBuoyantPressure
)

I hope this helps.

Shaun

Hello Shaun, thank you very
 

Hello Shaun,

thank you very much for your reply - I'll check it out ;-)

best regards, Stefan

try GroovyBC
 

Hi Stefan,

Search for groovyBC. That is an external package that lets you set boundary conditions based on any formula you want. I am sure it will help your case. Easy to install too..

Prapanj

Hi to evrybody!
Is there any inplementation of this time dependent fixed value for the 1.5 release?
Tanx