Discussion Forum

COMSOL has an application module (actually, it will take two application modules) to solve the FSI problem. I do not see the advantage of doing it again yourself unless you just want to do that for some reason. It will be a challenge enough just to figure out from the example FSI problems that come with COMSOL how to do it. Then learn from that, and apply it to your problem.

Hi,
I want to solve the set of equations by considering the effect of deformation of beam on the fluid pressure at each time step. For this, I can use either finite difference method which is difficult to program or Comsol(PDE mode or writing own script)
I saw the example in comsol which uses ALE method to solve the flow from moving boundaries.
My problem is that I don't know how to integrate this set of equations in Comsol which would be a different and a little simpler approach.
I am using following set of equations.

1. Steady state Incmpressible Navier-Stokes equations

rho(u*du/dx + v*du/dy) = -dp/dx + mu(d2u/dx2 + d2u/dy2)

rho(u*dv/dx + v*dv/dy) = -dp/dy + mu(d2v/dx2 + d2v/dy2)

du/dx + dv/dy = 0

2. Deformation of the beam

y = Po*sin(omega*t)*x^3/(3EI)
where Po*sin(omega*t) is the assumed initial pressure causing deflection of the beam. I am assuming steady state velocity of the fluid since the deformation from the initial calculation is small.



Thanks
Pranav

Interestingly, we just watched an FSI webinar on this subject from COMSOL. The FSI application mode comes with the structural mechanics and/or MEMS module. The ALE capability comes with the base package as well as the general PDE solver capability.

If you are not going to purchase the extra modules, and you don't want to use the built-in solvers for Navier-Stokes and ALE, but you want to use the base modules instead, then you will have all the tools you need. You just need to learn how to program up the equations in PDE mode. There are several examples on how to do that available in the model library and online papers.

I am going through the PDE modes. I think that, for my problem, General form of pde is most suitable since the equations are non-linear.
Would you please send me an example of a problem solved using pde modes or give me a direction to begin with?


Thanks
Pranav