Seeing Through Solids: Discovery and Applications of Photoacoustics

Brianne Costa 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 Costa 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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Guest René Christensen February 28, 2018

Today, guest blogger René Christensen of GN Hearing discusses including thermoviscous losses in the topology optimization of microacoustic devices. Topology optimization helps engineers design applications in an optimized manner with respect to certain a priori objectives. Mainly used in structural mechanics, topology optimization is also used for thermal, electromagnetics, and acoustics applications. One physics that was missing from this list until last year is microacoustics. This blog post describes a new method for including thermoviscous losses for microacoustics topology optimization.

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Caty Fairclough January 29, 2018

Micromirrors have two key benefits: low power consumption and low manufacturing costs. For this reason, many industries use micromirrors for a wide range of MEMS applications. To save time and money when designing micromirrors, engineers can accurately account for thermal and viscous damping and analyze device performance via the COMSOL Multiphysics® software.

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Ajit Bhuddi November 8, 2017

Suppose you have a very long system with a constant cross section: a fluid-filled pipe. Modeling this system is computationally expensive and time consuming. Using a guided wave propagation approach, you can model a cross section of the system and compute the guided waves along it. You can represent such waves by means of dispersion curves. Here, we discuss a coupled analysis considering air and water as the internal fluids. We also analyze the system dynamics using dispersion curves.

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