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sanjay January 18, 2012 00:25

simulating wing motion of an insect???
2 Attachment(s)
Hi, I am trying to simulate the motion of a insect wing (uniaxial motion i.e just rotation) in CCM+. I have selected the following physical conditions.

3 dimesnsional
implicit unsteady
constant density
segregated flow
K-epsilon model

Can nay one tell me how to specify motion for the wing.


ping February 13, 2012 03:17

simple next step - create a field function which specifies the rotation velocity of the wing as a function of radius - eg using a sin function and a local cylindrical coordinate system. then for the wing change morpher setting to grid velocity and apply the field function.
we are promised overset mesh is version 7.02 coming soon and this will make this case faster to solve since the morpher adds another set of equations to solve.

sanjay February 13, 2012 04:27

thanks for the reply, Il work on it and get back for more discussion


ryancoe February 16, 2012 09:41

You could also create a field function, as ping suggests, but use the rotation and translation motion module to move the entire domain. This would be less computationally intensive than morphing the mesh.


abdul099 February 18, 2012 08:26

Ryan, he needs to morph the mesh since not all of the domain will rotate. Just the wing will do the rotation while the body won't.

Sanjay, you can also directly apply a motion as boundary condition for the morpher. That's much easier than creating a field function specifying the grid velocity etc.
I agree to ping that overset mesh (once it's released, should be at beginning of march) will be a better approach, since morphing sometimes needs much more computing time than the flow solver and needs a significant amount of memory, especially on big meshes.

ryancoe February 18, 2012 10:54

Didn't realize there was a body involved. Good catch!

sanjay March 6, 2012 02:53

2 Attachment(s)
thanks a lot for those replies.
I decided that I will first do 2D simulation of flapping and then go for 3D

Can any one tell me how to create the flapping in 2D


alireza_b May 11, 2012 06:44

Dear users.
I write a UDF for flapping wing for fluent and compiled it and dont have any problem.
But i can not use dynamic mesh?
can you help me.
1- in gambit creat a zone aroud airfoil and implement a interface boundary condition.
2- in fluent i use define-interface
3- enable dynamic mesh with layering and smoothing.
4- selected airfoil and use UDF.
But airfoil is fixed and dont move!
fluent have this error:
cg motion is incorrect.

abdul099 May 11, 2012 17:40

alireza_b, this is the star-ccm+ forum.

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