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Harmonic Fluids

By Troy Parker,2014-06-30 13:50
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Harmonic Fluids

    Harmonic Fluids () 3 ppt Changxi Zheng Doug L. James

    Cornell University

Introduction

(1)

    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 [1933], and large texts have since been written about them [Leighton

    1994]. Recently, van den Doel [2005] proposed bubbles as primitives for fluid sound synthesis, and

    synthesized compelling sounds using stochastically excited modal sound banks.

    4 we

    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

    wave equation.!!

    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)

    6

    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.

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