Standing waves on arbitrary membrane

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SUMMARY

The discussion centers on the generation of standing waves on an arbitrary membrane stretched over a closed loop of wire. The participant, Andy, posits that it is possible to vibrate the membrane at specific frequencies to produce fundamental modes of vibration, based on the 2D wave equation with zero-displacement conditions. However, the conversation reveals that real-world membranes, due to their elastic properties, may not satisfy the wave equation, leading to complications in generating multiple modes of vibration. The implications of irregular boundaries on the number and spacing of vibrational modes are also explored.

PREREQUISITES
  • Understanding of the 2D wave equation
  • Knowledge of boundary conditions in wave mechanics
  • Familiarity with the properties of elastic membranes
  • Basic concepts of vibrational modes and frequencies
NEXT STEPS
  • Research the solutions to the 2D wave equation with arbitrary boundary conditions
  • Explore the effects of elasticity on wave propagation in membranes
  • Investigate the relationship between boundary shape and vibrational modes
  • Learn about the principles of standing waves in different geometries
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Physicists, engineers, and students interested in wave mechanics, particularly those studying vibrational phenomena in elastic materials and complex geometries.

the4thamigo_uk
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My (probably misguided) intuition says the following :

'Take a closed loop of wire and bend it into any arbitrary shape so that it lies flat on a table. stretch a membrane over it (i.e. a soap membrane say). Then, I should be able to vibrate it at just the right frequency to generate (at least) a fundamental mode of vibration.'

In other words I think my intuition is telling me that there are solutions to the 2D wave equation with a zero-displacement condition on an arbitrary closed boundary.

Is my intuition right or wrong? If wrong, why?

Also, my intuition is telling me that for a complicated irregular boundary that there would be fewer modes of vibration or that they would be spaced more widely apart in terms of frequency.

Thanks

Andy

Additional:

If the intuition is incorrect, then is this something to do with the fact that a real world membrane is elastic and can stretch in ways that don't satisfy the wave equation?
 
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I would think you'd generate several modes for different spatial scales that, in a real membrane, would quickly attenuate the whole membrane to the steady state as tey compete with each other.

A circle only has one spatial scale (the radius or diameter if you like), the arbitrary shape could have several.
 

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