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Modeling pressure waves

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Hi, I want to model pressure waves induced by a thermal load. Is there any way to do this in comsol? Perhaps by using the plane stress module? But how do I couple it to temperature, or make it temperature dependent?
Thanks

5 Replies Last Post 2012/04/12 17:16 GMT-4
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Hello Trent Mclellan

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Posted: 1 decade ago 2012/04/11 14:31 GMT-4
I'm trying to do something similar. COMSOL support told me to use the linear elastic model, defining pressure and shear wave velocities, but I haven't had any luck in producing a wave from thermal load. Have you made any progress?
I'm trying to do something similar. COMSOL support told me to use the linear elastic model, defining pressure and shear wave velocities, but I haven't had any luck in producing a wave from thermal load. Have you made any progress?

Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 2012/04/12 8:25 GMT-4
If you are trying to model wave propagation you should do a transient solid mechanics analysis with very small time steps to capture the propagation. The wave propagation speeds will depend on the material properties. Can you elaborate on the type of problem you’re modeling, because usually thermal transients have a much larger time scale than that associated with wave propagation in solids.

Nagi Elabbasi
Veryst Engineering
If you are trying to model wave propagation you should do a transient solid mechanics analysis with very small time steps to capture the propagation. The wave propagation speeds will depend on the material properties. Can you elaborate on the type of problem you’re modeling, because usually thermal transients have a much larger time scale than that associated with wave propagation in solids. Nagi Elabbasi Veryst Engineering

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Posted: 1 decade ago 2012/04/12 11:41 GMT-4
I'm using thermal stresses in a transient study, pressure wave velocity of 1000 m/s, time steps of 1e-4, and a heat input that lasts for one time step. I see a temperature increase, as well as a local acceleration in the appropriate direction, but no wave propagation.
I'm using thermal stresses in a transient study, pressure wave velocity of 1000 m/s, time steps of 1e-4, and a heat input that lasts for one time step. I see a temperature increase, as well as a local acceleration in the appropriate direction, but no wave propagation.

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Posted: 1 decade ago 2012/04/12 14:12 GMT-4
If the wave speed is 1000 m/s and your step size is 1e-4 you will at most see waves that are propagating in steps of 0.1 meters. Also make sure that COMSOL is actually using the step size you specify, and not allowed to grow the step automatically.

Nagi Elabbasi
Veryst Engineering
If the wave speed is 1000 m/s and your step size is 1e-4 you will at most see waves that are propagating in steps of 0.1 meters. Also make sure that COMSOL is actually using the step size you specify, and not allowed to grow the step automatically. Nagi Elabbasi Veryst Engineering

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Posted: 1 decade ago 2012/04/12 17:16 GMT-4
My time scale is .0001 s to .01 s, in .0001 s steps. I specified step size in the study parameters, and while I see an acceleration at the side where I introduce the heat flux, it never propagates through the model.
My time scale is .0001 s to .01 s, in .0001 s steps. I specified step size in the study parameters, and while I see an acceleration at the side where I introduce the heat flux, it never propagates through the model.

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