I am using CFX I want to simulate the motion of sphere(structure). 2D: The motion of cylinder in channel flow 3D: The motion of sphere in tube flow

But I don't know what i have to do.

Welcome any advice and any examples(very good)

Thanks a lot

Hi there,

I can give you some references for the theoretical point of view:

Concerning the motion of the sphere, you might want to have a look at the paper

Maxey and Riley, 1983, Physics of Fluids, vol.26, page 883, "Equations of motion for a small rigid sphere in a nonuniform flow".

This should give you some introduction and details on the problem in general (you don't need to look at all the equations, just the physical processes).

You can also find some good textbook on a cylinder moving in a fluid, with the fameous Von Karman vortex street, etc.. for example: the book of Schischling (not sure about the spelling) on the theory of the boundary layer. This should also give you a first approach to the problem.

What symmetry are you looking at? if any?

Then you will have to decide on boundary conditions and initial conditions (if the problem is time dependent). This depends on exactly how you specify your problem, but I guess you will have mainly an inflow and outflow, together with some (moving) wall boundary condition (since you probably want to move the flow/channel, rather than the cylinder/sphere).

PG