How to define a value that is evaluated through iteration in COMSOL 4.0

[Urmi Roy]

Hi,

Here are the details in as concise a manner as possible:
1. I'm using In-compressible Navier Stokes Module in laminar flow, time dependent solution.
2.I have a rectangular region in which I have some fluid.
3.there are cilia inside the fluid, which move with a time and space-varying velocity V=ycos(5t+6x)\
4. However, the movement of the cilia is oscillatory, so the net velocity of the fluid is some other value, say U
5. there is a bulk/volume force acting on the fluid, which is a function of both U and V...say |F|=(U-V)...
6. Obviously, U is also time varying, and determined by V...so how do I define it in COMSOL?

 

[NateD]

To define U in COMSOL, you can set up a time-dependent expression for U that contains the velocity of the cilia, V. This expression can then be used in the definition of the bulk/volume force, |F|. For example, you may set up U as U = ycos(5t+6x) + A, where A is a constant that determines the magnitude of the net velocity of the fluid. You would then use this expression for U in the definition of |F|, such that |F|=(U-V). Additionally, you may need to set up a time-dependent expression for the pressure gradient in order to solve the Navier Stokes equations.Hope this helps!