How to Model Fundamental Sources in Enclosed Spaces

James Gaffney January 17, 2019

As the story goes, Archimedes was struggling with a case of suspected golden crown fraud. While taking a bath, inspiration hit: Submerging an object displaces the same amount of water as the object’s volume, so he could expose any dilutions to the gold. Archimedes was so pleased, he yelled “eureka!” But would anyone have heard the now-famous shout? Using simulation, we can evaluate the acoustics of resonant and reverberant enclosed spaces, like bathrooms, and how they respond to fundamental sources.

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Jinlan Huang December 20, 2018

Piezoelectric devices are widely used as sources to generate sound waves or receivers to detect acoustic signals. In applications such as ultrasound imaging and nondestructive testing, the same transducer can be used as a transmitter to send a source signal and receiver to detect echoes. Modeling these devices often requires transient analyses with time of flight as output. Let’s discuss how to use the COMSOL Multiphysics® software to model a piezoelectric device as both a transmitter and receiver.

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Thomas Forrister December 4, 2018

When modeling acoustic devices, it’s often enough to account for linear propagation alone, even though nonlinearities are always present. However, when the signaling amplitude reaches high levels in a design, nonlinear effects become important. Engineers can include nonlinear effects in simulations by taking advantage of the Nonlinear Acoustics (Westervelt) feature in the COMSOL Multiphysics® software, as demonstrated by an exponential horn example.

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Brianne Christopher August 30, 2018

In 1880, Alexander Graham Bell wrote a letter to his father, saying: “I have heard articulate speech by sunlight! I have heard a ray of the sun laugh and cough and sing!” He was talking about his latest success, the photophone, which he called his “greatest invention” shortly before his death. The photophone did not revolutionize the field of imaging, but an unintended effect Bell noticed while developing it did…

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Thomas Forrister August 17, 2018

“If you want to find the secrets of the universe, think in terms of energy, frequency, and vibration.” — Nikola Tesla Can we “see” sound? Not directly, but we can come close. By changing our perspective, we can learn a lot about the nature of acoustics. One way to observe acoustics phenomena is by studying standing waves in a solid medium known as a Chladni plate. A special technique creates patterns on the plate that reveal sound’s physical nature.

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Thomas Forrister July 23, 2018

The main design goal for a loudspeaker array is to achieve wider sound coverage than a single speaker could provide. At the same time, the radiation pattern of the array must be indistinguishable from that of a single speaker. One method for producing radially distributed sound for multiple loudspeakers is with a Bessel panel. By analyzing a benchmark model of a Bessel panel system, engineers can optimize the design of loudspeaker arrays and other acoustics systems.

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Kirill Shaposhnikov June 18, 2018

A thorough analysis of a loudspeaker driver is not limited to a frequency-domain study. Some desirable and undesirable (but nonetheless exciting) effects can only be caught by a nonlinear time-domain study. Here, we will discuss how system nonlinearities affect the generated sound and how to use the COMSOL Multiphysics® software to perform a nonlinear distortion analysis of a loudspeaker driver.

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Brianne Christopher May 29, 2018

The Doppler effect, or Doppler shift, occurs when the movement of an observer relative to a source (or vice versa) causes a change in wavelength or frequency. Discovered by Austrian physicist Christian Doppler in 1803, this phenomenon is experienced in many different ways, such as when an ambulance passes you by and you hear an audible change in pitch. Using the COMSOL Multiphysics® software, you can model the Doppler effect for acoustics applications.

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Caty Fairclough April 27, 2018

Picture a classroom filled with students. At the front, a teacher discusses room acoustics, including the underlying theories and acoustics phenomena involved. To help students visualize these concepts, the teacher has created a simulation app. This app, which is accessible through a web browser, enables students to dynamically alter parameters and see the results, creating a vivid learning experience. At the Technical University of Munich (TUM), several such apps are already being used, providing benefits to teachers and students alike…

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Henrik Sönnerlind April 13, 2018

When a tuning fork is struck, and held against a tabletop, the peak frequency of the emitted sound doubles — a mysterious behavior that has left many people baffled. In this blog post, we explain the tuning fork mystery using simulation and provide some fun facts about tuning forks along the way.

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Mads Herring Jensen March 19, 2018

The boundary element method (BEM) is included in the Acoustics Module as a physics interface. This interface, available as of version 5.3a of the COMSOL Multiphysics® software, can be seamlessly combined with interfaces based on the finite element method (FEM) to model, for example, acoustic-structure interaction problems. This functionality expands the range of problems that can be solved with the Acoustics Module. Here, we look into the BEM functionality, examples, and BEM-specific postprocessing.

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