Harmonic Fluids () 3 ppt Changxi Zheng Doug L. James
How to simulate synchronized physics-based sounds for familiar splashes and splatters？ What causes fluid sounds?
(2) Perhaps surprisingly, the majority of sound from a splashing droplet of water
arises from harmonic vibrations resulting from the entrainment (creation) of millimeterscale air
bubbles (see Figure 1).
(3) Basically, the bubble oscillator stores potential energy as compressed air and surface
tension, and kinetic energy as surrounding fluid vibrations. The important role of these tiny “acoustic bubbles” 微小发声水泡 in water sound generation has been recognized for nearly a century since
pioneering work by Minnaert , and large texts have since been written about them [Leighton
1994]. Recently, van den Doel  proposed bubbles as primitives for fluid sound synthesis, and
synthesized compelling sounds using stochastically excited modal sound banks.
choose to model sound wave propagation
and radiation in fluids by assuming they
are a sequence of static problems.!! Given
the harmonic nature of bubbles, we can
efficiently model sound waves in the
frequency-domain using the Helmholtz
5 Our approach:
We model the creation of bubbles by air
entrainment at the fluid surface; the
advection水平对流 of these bubbles with
the fluid flow; the surface vibrations
induced by the bubbles’ vibrations; and the
radiation of these vibrations into the air,
producing sound (see Figure 3).
We weight （加权）each oscillator by its
bubble-to-ear acoustic transfer function, which is modeled as a discrete Green’s function of the Helmholtz equation. (赫尔姆霍茨方程 核心算法)
To solve potentially millions of 3D Helmholtz problems, we propose a fast dual-domain multipole (声场多极子) boundary-integral solver.
Our main contribution is a parallel algorithm for estimating sound radiation.