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Janice April 3, 2001 22:36

Fluid-Structure Interaction
I have been working on comparing water wave loads(force) on partially submerged circular cylinders ,my objective is to compare the numerical results for wave loads with those of experimental values.

I have been working on such a flow visualisation system where I can estimate the velocity and vorticity around the submerged cylinder at all over the fluid-domain and I wish to estimate the fluid force (due to water waves) on the cylinder making use of this velocity and vorticity data.Is there any software available in any public-domain that could solve the above problem for me?

PS:= please suggest me any literature on the above problem

Peter Attar April 4, 2001 12:49

Re: Fluid-Structure Interaction
Unless I've misunderstood your problem I don't think you really want a true fluid-structure solver..unless the cylinder deforms and this deformation interacts with the flow over the body you should just be able to use a pure fluid solver.

Janice April 4, 2001 18:53

Re: Fluid-Structure Interaction
Mr Attar i sincerely appreciate your suggestion and I would be very glad if you could suggest me some literature on the problem i put forth in my last message.

Thank You

Peter Attar April 4, 2001 20:32

Re: Fluid-Structure Interaction
Take a look at some potential flow solution methods. A web search for codes that are designed for the interaction of waves with ships(of which I've seen a couple..can't remember the names though sorry) should give you an idea of how they are done. Katz and Plotkin is a good low speed aerodynamics book which will also help you with the potential flow codes.

clifford bradford April 10, 2001 17:52

Re: Fluid-Structure Interaction
I don't think you need a CFD program at all. If you're abe to measure the velocity in your flowfield then you should be able to determine the amount of force on the cylinder by integrating the momentum flux over a control volume enclosing the cylinder to get the force. this is how wind tunnel measurements are used to obtain the drag. See Chapter five of "Fundamentals of Fluid Mechanics" by Munson, Young and Okiishi or any other intruductory fluid mechanics book.

Apurva Shukla April 11, 2001 01:54

Re: Fluid-Structure Interaction

There is a good review article in this years (2001) Annual Review of Fluid Mechanics by Kenneth Hall titled "Modeling of FSI", pp.445-490.

Hope it may help you.

Good Luck


Abhijit Tilak April 13, 2001 01:09

Re: Fluid-Structure Interaction
hey apurva,

The volume u mentioned is not available in our insti library as yet, do u remember what month was that published? Do you know any website where it can be downloaded? Let me know

Abhijit Tilak Aero Engg Dept IIT Bombay

Apurva Shukla April 13, 2001 02:06

Re: Fluid-Structure Interaction
Hi Abhijit,

"Annual Review of Fluid Mechanics" is a yearly publication. You find it in the reference section of the IITB library, not in the Journal Section. Hopefully by now the 2001 volume might have come.



ananda himansu May 3, 2001 16:37

Re: Fluid-Structure Interaction
if the waves are not large enough relative to the cylinder to cause it to deform, then peter attar is right: you do not need a fluids-structure interaction program, just a CFD program.

to find the forces at any instant, what you need is to integrate the pressure over the submerged surface of the cylinder at that instant of time. you can average such an instantaneous force over time to find the average force.

from the velocity and vorticity fields, you must first recover the pressure by solving a pressure poisson equation. sorry, i cannot point you to any specific reference paper/book or any public domain software.

some books on CFD will explain the velocity/vorticity formulation and how the pressure is recovered using a pressure poisson equation, and they would provide references. as for software, you can search CFD-ONLINE.

ananda himansu May 3, 2001 16:46

Re: Fluid-Structure Interaction
oops, i forgot to mention in my response that if the cylinder moves due to the wave forces, you do need a fluid-structure interaction program. you still solve the pressure poisson equation in the same way at any instant, but thereafter you have to use the resultant forces on the cylinder to integrate the motion of the cylinder (knowing its mass distribution) to find the cylinder position and orientation at the next time level. then you compute the pressure again, etc.

i have no clue as to how you obtained the velocity and vorticity fields, but it may be that that program has an option to provide the pressure field, or could be modified to calculate also the pressure field.

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