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Mehdi Naderi (mnader4)
Member
Username: mnader4

Post Number: 19
Registered: 12-2006
Posted on Friday, November 02, 2007 - 05:33 pm:   

Hi,
I will appreciate if you answer my question.
Suppose we have a fin (clamped at one end and free at the other end) which fluctuates sinusoidally. Can flexpde solve the velocity field around fin?
If no how can I make it easier untill my problem be solved?
Is there any topic posted here similar my problem?
Thank you so much again,
Mehdi
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Robert G. Nelson (rgnelson)
Moderator
Username: rgnelson

Post Number: 981
Registered: 06-2003
Posted on Friday, November 02, 2007 - 06:07 pm:   

You should be able to do this with a moving mesh along the lines of our sample problem "Samples|Moving_Mesh|2d_cyl_piston.pde"

You will need an analytic expression for the boundary of the fin vs time.

The piston problem treats a compressible gas, but you can replace the equations with incompressible ones.

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Mehdi Naderi (mnader4)
Member
Username: mnader4

Post Number: 20
Registered: 12-2006
Posted on Tuesday, November 06, 2007 - 12:41 pm:   

Dear Mr. Nelson,
Thank you so much.
I am working on that problem.
I will appreciate if you answer my questions about pressure equation:
Note: my problem is time dependent
1-For air as fluid around the fin: I used pressure equation of 2d_cyl_piston.pde.
P: dt(P) + u*dx(P)+v*dy(P) + gamma*P*(dx(u)+dy(v)) = div(grad(P))
2- for water as fluid:
I used:
p: dt(p) +u*dx(p)+v*dy(p)= (p-p0+penalty*rho)*(dx(u)+dy(v))
(I simplified dt(dens) + div(dens*U) = 0 and replaced dens with pressure: dense=(p-p0)/penalty+dens0)
Am I right?
Regards,
Mehdi

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