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Focus Session:Advanced Topics in Acoustics
Mads J. Herring JensenTechnical Product Manager, Acoustics
Boston, October 2015
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Schedule• Examples of advanced
acoustic applications• The acoustics roadmap• The invited presenters
Thermoviscous scattering off a small elastic particle modeled using thermoelasticity. See COMSOL Blog in October.
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Advanced Acoustic Applications• Non out-of-the-box problems
– Manual coupling of physics and/or spatial dimensions– User defined equations and expressions
• Optimization• Models and features that drive the development of the
Acoustics Module– Customer inputs and suggestions– Results form the academic world
• All this is possible in COMSOL Multiphysics!
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Advanced Acoustic Applications
Solve for propagatingmode in waveguide(p, u, T)
Couple:• Pressure Acoustics and Thermoacoustics• End impedance• Lumped speaker model
• Port Conditions in Thermoacoustics
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Advanced Acoustic Applications
Miniaturetransducer
Grille
• Non-linear Losses in Fluid
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Advanced Acoustic Applicationsz
• Transient model• Geometric non-linearity in solids• Material models for rubber etc.• Linear acoustics• Harmonic distortion products
(frequency doubling)• Total harmonic distortion (THD)
• Non-linear Losses in Structure
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Advanced Acoustic Applications
Yoak
Coil
Spout
Magnet
V = pin
Circuit model
I = Qin
V0 ~ ~
0
p1 p2
ear canal
pinna
ear-drum
hearingaid
• Device Modeling and System Modeling– Sub-Models
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Advanced Acoustic Applications
FEM Ray Acoustics
Intensity matchat 1 m
Phase matchat 1 m
• Realistic Ray Acoustics Speaker Source: FEM to Ray Coupling
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Special Operators and Modeling Doc• In the documentation look for Built-In Operators:
– withsol() and with()– at2(), at3()– timeint()– sum()
• In the Acoustics Module User’s Guide have a look at the Modelling chapters
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The Acoustics Roadmap• Time explicit methods using
discontinuous Galerkin (DG)• Ports in acoustics• Physics induced mesh• Boundary elements (BEM)
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The Acoustics Roadmap• Time Explicit Methods using Discontinuous Galerkin (DG)
• Memory efficient• Solve large problems in 3D!• Intrinsic numerically stable
for, for example, Linearized Euler
• Conservative form• Scales well on clusters
Flow
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The Acoustics Roadmap• Boundary Elements (BEM)
Interior BEM• Large radiating bodies• “Far-field” for vibrating structures• FEM-BEM models
Exterior BEM
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The Invited Presenters• Modeling Metamaterials with a Time-Domain Perfectly
Matched Layer FormulationHisham Assi and R. S. C. CobboldUniversity of Toronto, Toronto, ON, Canada
• PA Loudspeaker System Design Using Multiphysics SimulationRiccardo BalistreriQSC Audio Products, LLC., Costa Mesa, CA, USA