k-Wave

1. maryam.parto
   

   Member
   Joined: Mar '15
   Posts: 12

   Hi
   I want to know that the pressure I define for a source point is force applied over an area of one meter squared or an area of one dx squared?
   Thanks for your attention.

   Posted 8 years ago #

2. bencox
   

   Developer
   Joined: Mar '10
   Posts: 292

   Good question. Sources in k-Wave can raise non-trivial issues, but if you want a one-word answer, it is dx^2 not 1 m^2. For example, a pressure source of p Pascals applied evenly over a plane of M*M pixels of size dx^2, (in other words a total force of p*M^2*dx^2 Newtons) will be approximated well by using a weight of p at each source point.

   There is another aspect to be aware of. For initial pressure distributions, defined using source.p0, or sufficiently long time-varying sources, defined using source.p, the units will stay consistent. So if source.p0 or source.p are defined in Pascals, then the measured signal will also be in Pascals. However, if the duration of the time-varying source is too short - comparable to dx/medium.sound_speed then the measured amplitude will be lower than expected. If this is your situation I can explain further, but it may take quite a long post.

   Also remember that when applying an initial pressure distribution, the resulting wave travels both outward and inward (or both left and right in the 1D case), so a factor of 2 may be required, depending on what you are trying to model.

   Hope that helps,
   Ben

   Posted 8 years ago #

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