Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Rigorous Science

Popping "vacuum bubbles" loudness

+1
−0

Stun-wizards specialize in blinding and deafening opponents at a distance. To do so, they can exert their magical power to manifest a spherical region of vacuum by essentially "telekinetically" pushing air out of the region. When the wizard releases their spell, air rushes back into the space, presumably with a loud "bang".

How do you calculate the acoustic loudness (in sound pressure, dB) of a sphere of vacuum, with arbitrary radius r, collapsing at a regular atmospheric pressure?

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

This post was sourced from https://worldbuilding.stackexchange.com/q/166370. It is licensed under CC BY-SA 4.0.

0 comment threads

1 answer

+0
−0

The collapse of bubbles on various scales has actually been an area of research for quite some time. Analyses are typically numerical, and rely on something known as the Rayleigh-Plesset equation, which tells you how the bubble's radius varies as it oscillates or collapses. If you know the pressure inside the bubble and the pressure far from the bubble, you can adequately predict its collapse by numerically solving the differential equation - you're not going to get an analytic solution in the general case.

Sound waves emitted by oscillating and collapsing bubbles - due to external perturbations - are discussed in Section 7 of Lauterborn & Kurz (2010). One of the earliest papers on solving the requisite equations is Hickling & Plesset (1964), which discusses the case of a bubble collapsing (and rebounding) in water. You may find that to be a good starting point. Regrettably, you'll have to carry out the numerical simulations on your own.

Some notes:

  • The study of bubbles typically involves bubbles on the centimeter to nanometer scale; beware of assumptions that may become invalid at macroscopic scales.
  • Solving the equations should give you the pressure of the shock waves; from there, you'll have to convert to decibels given the pressure of the external medium.
  • This is a problem for which there is, unfortunately, no simple (i.e. analytic) solution.
History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.

0 comment threads

Sign up to answer this question »