k-Wave

1. p_acoustics
   

   Member
   Joined: Apr '24
   Posts: 3

   Hi,

   Thanks for the great software. k-wave is not only a great software, the research that comes with it and the papers published using k-wave really helps the users to understand the physics of acoustics.

   I have a question, if you have a cylinder of sources (multiple sources are arranged in a way that they shape an imaginary cylinder), how could we stop the acoustic sources to emit sound from their face in-ward and not out-ward. Because if the sound propagates in-ward (toward the inside of the cylinder), then it will eventually interfere with the outward propagation. I am interested in both far field and nearfield results.

   I looked into the research on bowl transducer (multiple sources are arranged to shape a bowl) but I did not see anything related to acoustic emission from the back of the bowl).

   http://bug.medphys.ucl.ac.uk/papers/2016-Martin-IEEETUFFC.pdf

   I tried putting hard material (high speed of sound and high density) inside the cylinder but it did not work. I also tried to increase the absorbsion inside the cylinder and was not successful. There is no PML that we could put inside the cylinder either. I also tried to go with the half of the cylinder, but the interference from inside of the cylinder eventually will happen.

   I appreciate your help.

   many thanks

   p.s: I use k-wave for python.

   Posted 7 months ago #

2. p_acoustics
   

   Member
   Joined: Apr '24
   Posts: 3

   
   

   Posted 7 months ago #

3. p_acoustics
   

   Member
   Joined: Apr '24
   Posts: 3

   I saw that maybe I did not write it clearly:

   If I have an array of rectangular sources arranged in a way (with some angle to create a convex shape) that they shape an imaginary cylinder together, and the purpose is to create sound waves outside of this cylinder, like a large cylindreical source made of mosaic of transducers.

   How could we stop the acoustic sources from emitting the sound waves inward. Because, if the sound propagates inward (toward the inside of the cylinder), then the sound waves will eventually reach the other side of the cylinder and pass it and they will interfere with the outward propagation. I am interested in both far-field and near-field results.

   Also, how could we create a baffle between the square sources.

   many thanks

   Posted 7 months ago #

4. bencox
   

   Developer
   Joined: Mar '10
   Posts: 292

   Hi p_acoustics,

   Interesting question. There's not an obvious way to do it.

   One way to make a source that is directional is to put a monopole source (source.p) and a dipole source (source.ux, ...) at the same source point, ie. source.p_mask = source.u_mask. If the scaling is right (pressure and velocity related by the acoustic impedance), the waves propagating in one direction will destructively interfere and in another constructively interfere. Also note that to have the sources at exactly the same point it will be necessary to turn off the staggered grid, setting the UseSG option to false. Also note that the pressure source is advanced in time compared to the velocity source by half-a-timestep, so source.p may have to be shifted back by that much.

   I'd be interested to know if it works!

   Best wishes
   Ben

   Posted 3 months ago #

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