Acoustics & Vibrations Blog Posts
Seas of Change for Wind Turbines
Wind turbine noise is a (hotly disputed) topic that we’ve mentioned on the blog before. While research into noise production by wind farms is still being debated among researchers, one way we’ve found to overcome these noisy turbine troubles is to place turbines offshore where they can’t be heard and, conveniently, high winds with more regularity make energy production more effective. However, a question that comes to mind is: What impact do offshore wind farms have on marine life?
Natural Frequencies of Immersed Beams
Today, we invite guest blogger Nagi Elabbasi of Veryst Engineering to share a modeling example of immersed beams. When thin structures such as beams, plates, or shells are immersed in a fluid, their natural frequencies are reduced. The fluid also affects their mode shapes and is a source of damping. This phenomenon affects structures across a wide range of industries and sizes, from micro-scale structures (e.g. MEMS actuators) to larger structures (e.g. ships).
How to Model Thermoviscous Acoustics in COMSOL Multiphysics
When modeling acoustics phenomena, particularly of devices with small geometric dimensions, there are many complex factors to consider. The Thermoviscous Acoustics interface offers a simple and accurate way to set up and solve your acoustics model for factors such as acoustic pressure, velocity, and temperature variation. Here, we will demonstrate how to model your thermoviscous acoustics problems in COMSOL Multiphysics and provide some tips and resources for doing so.
Theory of Thermoviscous Acoustics: Thermal and Viscous Losses
When sound propagates in structures and geometries with small dimensions, the sound waves become attenuated because of thermal and viscous losses. More specifically, the losses occur in the acoustic thermal and viscous boundary layers near the walls. This known phenomenon needs to be considered to evaluate how these losses affect thermoviscous acoustics systems in order to build accurate models and match experimental measurements.
MEMS Microphone Model Presented at ASA 166 in San Francisco
I recently had the pleasure of preparing a small contribution to the 166th Meeting of the Acoustical Society of America (Fall 2013) together with Wade Conklin and Jordan Schultz from Knowles Electronics. Wade presented our paper entitled “Characterization of a microelectromechanical microphone using the finite element method”. The work consisted of implementing a virtual prototype of a Knowles MEMS microphone (the SPU0409LE5H microphone, see picture below) using COMSOL Multiphysics.
Thermoacoustics Simulation for More Robust Microphone Analysis
When performing an analysis on small-scale audio equipment, such as hearing aids, cell phones, and microphones, the obvious physical phenomenon that’s analyzed is pressure acoustics. However, there are other physics interactions that significantly affect these small devices, including electromechanical interactions and viscothermal losses. Most notably, thermoacoustics (the detailed modeling of acoustics including thermal conduction and viscous losses) is an often overlooked effect that can alter the results of a model. These effects are important in all devices with small length […]
Starting Small with Sonar Dome Design
Starting the design process by testing on a small scale is often the best way to tackle issues affecting large objects, like a ship. Detailed in COMSOL News 2013, researchers at INSEAN, The Italian Ship Model Basin, used small-scale testing and then simulation to analyze the effect of placing a sonar system within the bulbous bow at the hull of a ship. Using a small-scale model of a bulbous bow, the researchers at INSEAN performed fluid-structure interaction experiments, and subsequently […]
Modeling Magnetostriction Using COMSOL Multiphysics®
If you have ever stood next to a transformer, you have probably heard a humming sound coming from it and wondered if there were bees close by. When you hear that sound the next time, you can rest assured that it’s not bees but the magnetostriction of the transformer core that is making that humming sound.
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