[balkrishna]

Hi ,
How should I model flow around a flapping wing in FLUENT . The aerodynamics involves vortex based methods . The problem I am facing is how should i update the geometry at every flap of the wing

[meb]

First take a look to this Foam related thread http://www.cfd-online.com/Forums/ope...nts-shape.html.
You will find an interesting discussion, including some links about the work of my group about moving mesh for FSI simulation of reed valve motion and by Frank Bos about the problem you are addressing.

Considering Fluent you have several options:

1) You can program your own UDF to prescribe the flapping movement to the boundary and use dynamic mesh feature of Fluent (with remesh). This is a feasible way. I did it in the past in a consultancy project about the simulation of the motion of a paper sheet inside a printing device (a challenging industrial application because we managed also the dynamic of the structure). Special care is requested for parallel UDF programming!

2) You can use immersed boundary. I'm not sure if the flapping problem can be handled. A commercial module is available for use it within fluent (http://investors.ansys.com/releasede...leaseID=406049).

3) You can use a mesh morphing tool, according to the approach proposed by Frank in the cited thread. I have developed the commercial module RBF Morph (http://www.rbf-morph.com). It's development was driven for managing shape optimisation in parallel for very large models. Since version 1.2 (http://www.rbf-morph.com/RBFMorph12) we have introduced a very fast sequential morpher that allows to update the mesh in a negligible time. We are currently investigating its application for transient solutions.

Regards.