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Model Frequency Information
Posted Mar 4, 2010, 2:46 p.m. EST 2 Replies
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Hello.
I wanted to know how I can get my wing to vibrate at specific frequencies, such as 2, 5, 8, 10 Hz, and so on. How can I input these frequencies into my model? I have attached a picture of the wing model.
The model is an airplane wing (airfoil) in a wind tunnel. The wing is held at the nose and the wing body is free to move. In the wing model I use multiple physics: Incompressible Navier-Stokes (fluid flow), Plane Strain (solid mechanics), and Moving Mesh-ALE (fluid-structure boundary). I am using the Structural Mechanics Module>Fluid-Interaction>Plane Strain setup for simulation.
The boundaries of the wing (inside the Navier-Stokes wind tunnel) are defined as “Moving wall”, and the wall boundaries of the wind tunnel are modeled as “No Slip”. I used the “Moving wall” condition for the wing surface because the wing surface moves with the velocity of the adjacent fluid-structure boundaries.
I want the wing to vibrate at specific frequencies in the air flow. So, how do I input these frequency values into the COMSOL simulation?
Thanks so much.
I wanted to know how I can get my wing to vibrate at specific frequencies, such as 2, 5, 8, 10 Hz, and so on. How can I input these frequencies into my model? I have attached a picture of the wing model.
The model is an airplane wing (airfoil) in a wind tunnel. The wing is held at the nose and the wing body is free to move. In the wing model I use multiple physics: Incompressible Navier-Stokes (fluid flow), Plane Strain (solid mechanics), and Moving Mesh-ALE (fluid-structure boundary). I am using the Structural Mechanics Module>Fluid-Interaction>Plane Strain setup for simulation.
The boundaries of the wing (inside the Navier-Stokes wind tunnel) are defined as “Moving wall”, and the wall boundaries of the wind tunnel are modeled as “No Slip”. I used the “Moving wall” condition for the wing surface because the wing surface moves with the velocity of the adjacent fluid-structure boundaries.
I want the wing to vibrate at specific frequencies in the air flow. So, how do I input these frequency values into the COMSOL simulation?
Thanks so much.
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2 Replies Last Post Apr 12, 2010, 2:12 a.m. EDT
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Posted:
1 decade ago
Hi
For me, my first toughts would be to say that to get an object to move in space one need to apply a force (or forces and moments), and you must constraint the airfoil tip or CoG or... to limit the movement to what you want.
Then either you work in the time domain and use an oscilaltory force at the correct frequency, or you can go to the harmonic domain (I'm not sure how to do that with all those physics and to get it correct, perhaps by separating it up with the segregate solver) and excite at a given frequency that you then scan over a spectra with a parametric sweep
In anycase a nice project
Good luck
Ivar
For me, my first toughts would be to say that to get an object to move in space one need to apply a force (or forces and moments), and you must constraint the airfoil tip or CoG or... to limit the movement to what you want.
Then either you work in the time domain and use an oscilaltory force at the correct frequency, or you can go to the harmonic domain (I'm not sure how to do that with all those physics and to get it correct, perhaps by separating it up with the segregate solver) and excite at a given frequency that you then scan over a spectra with a parametric sweep
In anycase a nice project
Good luck
Ivar
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Posted:
1 decade ago
Hello,
Thanks for your previous response.
I did constrain the wing (airfoil) at the tip and I am using a parametric sweep for the frequency. Force is applied to the bottom of the airfoil. However, I still do not see the displacement that I expected.
When I switch to (Post-Processing) Boundary, Deformed shape, Geometry edges, and Y-displacement, the wing does not appear to move (in the graph visualization); yet, displacement (on the y-axis) occurs according to the legend on the right.
Why don't I see the body of the airfoil move, which would be indicated by a colored outline of the airfoil shape in a new position post-simulation? What did I miss? I am not sure at this point.
Your input is most appreciated!
Thanks.
Thanks for your previous response.
I did constrain the wing (airfoil) at the tip and I am using a parametric sweep for the frequency. Force is applied to the bottom of the airfoil. However, I still do not see the displacement that I expected.
When I switch to (Post-Processing) Boundary, Deformed shape, Geometry edges, and Y-displacement, the wing does not appear to move (in the graph visualization); yet, displacement (on the y-axis) occurs according to the legend on the right.
Why don't I see the body of the airfoil move, which would be indicated by a colored outline of the airfoil shape in a new position post-simulation? What did I miss? I am not sure at this point.
Your input is most appreciated!
Thanks.
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