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pressure boundary condition for inviscid flow

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Old   November 10, 2007, 03:21
Default pressure boundary condition for inviscid flow
  #1
kharati
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As we know, if an airfoil oscillates in a fluid, pressure boundary condition on airfoil surface can be calculate by dp/dn=Du/Dt.n. if flow is viscous, acceleration of fluid on airfoil surface is aqual to accelaration of airfoil. how can we calculate acceleration of fluid on airfoil surface if flow is invicsid?
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Old   November 10, 2007, 12:15
Default Re: pressure boundary condition for inviscid flow
  #2
Peter Attar
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You asked this already..You are either prescribing the airfoil motion in which case you have a explicit expression for u(t) or you are doing a coupled simulation which you are computing u(t) using a set of structural equations of motion. Either way you have u(t)...
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Old   November 10, 2007, 17:20
Default Re: pressure boundary condition for inviscid flow
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Deepak
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Since this is a potential flow, there is a concept called "Apparent mass" to calculate acceleration of the fluid due to a body in motion. This is basically calculating the change in kinetic energy of the fluid.

for further assistance, go through Mechanics of Fluids by Currie.
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Old   November 10, 2007, 21:57
Default Re: pressure boundary condition for inviscid flow
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Peter Attar
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He said it was inviscid..not inviscid,incompressible and irrotational. Sounds to me like he's solving the Euler equations. This isn't rocket science..his/her airfoil is oscillating ie he/she has u(t) on the surface so he/she can differentiate analytically or numerically to get the acceleration.
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Old   November 11, 2007, 01:17
Default Re: pressure boundary condition for inviscid flow
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Deepak
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Oh..yeah i think I misunderstood it as a potential flow. But apparent mass is not restricted to Rocket Science.Its very well used in Fluid flow.

I think your suggestion is valid.
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Old   November 12, 2007, 03:27
Default Re: pressure boundary condition for inviscid flow
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winslow
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