Modelling accoustic waves/Piezo transducer

MichaelM · January 21, 2016, 05:30

Hallo everyone!

I am facing quite a big problem at the moment modelling the acoustic waves emitted by a Piezo transducer. What I need is an accurate model that generates pressure waves propagating through a fluid medium. I first tried a momentum source term inside a subdomain but a reasonable pressure fluctuation has the adverse side effect of too high velocities. I also tried it with a sinusoidal mass source term at a wall but the net mass flow is somehow positive and not zero (thus also not adequate). If I use a point mass source the problem is that the pressure wave propagation isn't unidirectional. I then thought about a more sophisticated model which aims to model the Piezo membrane itself. So I set up a model with an immersed solid inside my fluid domain but unfortunately CFX doesn't support compressibility effects when using an immersed solid.

Does anyone might have an idea how an acoustic wave can be modelled in CFX beside the models I already tried? I am grateful for any suggestions

Thanks a lot in advance!
M

ghorrocks · January 21, 2016, 17:16

I have a colleague who has modelled piezo membranes in CFX. He used moving mesh to do it and it was very successful.

https://www.researchgate.net/publica...e_flow_control

https://www.researchgate.net/publica..._jet_actuators

MichaelM · January 22, 2016, 06:16

Thanks so much Glenn! What would this forum be like without you

I was already setting up an Ansys Mutli-field code coupling case but this approach seems to be more straightforward and it looks like it does exactly what I wanted it to do

I hope you have a lot more colleagues for upcoming questions in the near future

M

January 21, 2016, 05:30	Modelling accoustic waves/Piezo transducer	#1
MichaelM New Member Michael Join Date: Oct 2015 Posts: 5 Rep Power: 10	Hallo everyone! I am facing quite a big problem at the moment modelling the acoustic waves emitted by a Piezo transducer. What I need is an accurate model that generates pressure waves propagating through a fluid medium. I first tried a momentum source term inside a subdomain but a reasonable pressure fluctuation has the adverse side effect of too high velocities. I also tried it with a sinusoidal mass source term at a wall but the net mass flow is somehow positive and not zero (thus also not adequate). If I use a point mass source the problem is that the pressure wave propagation isn't unidirectional. I then thought about a more sophisticated model which aims to model the Piezo membrane itself. So I set up a model with an immersed solid inside my fluid domain but unfortunately CFX doesn't support compressibility effects when using an immersed solid. Does anyone might have an idea how an acoustic wave can be modelled in CFX beside the models I already tried? I am grateful for any suggestions Thanks a lot in advance! M

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January 21, 2016, 17:16		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	I have a colleague who has modelled piezo membranes in CFX. He used moving mesh to do it and it was very successful. https://www.researchgate.net/publica...e_flow_control https://www.researchgate.net/publica..._jet_actuators

January 22, 2016, 06:16		#3
MichaelM New Member Michael Join Date: Oct 2015 Posts: 5 Rep Power: 10	Thanks so much Glenn! What would this forum be like without you I was already setting up an Ansys Mutli-field code coupling case but this approach seems to be more straightforward and it looks like it does exactly what I wanted it to do I hope you have a lot more colleagues for upcoming questions in the near future M