All posts by Mads Herring Jensen
A Thermoviscous Analysis of Acoustic Radiation Forces
This past July, I had the pleasure of attending the 22nd International Congress on Sound and Vibration. In addition to running the COMSOL vendor booth with my Italian colleague Gabriele, I was also a presenter at the event. My presentation was based on a paper I wrote with Henrik Bruus and Jonas Karlsen that focuses on how to determine acoustic radiation forces including thermoviscous effects. Let’s explore acoustophoretic effects in greater detail and the research findings highlighted in my presentation.
Modeling Room Acoustics with COMSOL Multiphysics
When inside a room — a conference room, concert hall, or even a car — everyone has an opinion of when the “acoustics” are good or bad. In room acoustics, we want to study this notion of sound quality in a quantitative way. In short, room acoustics is concerned with assessing the acoustics of enclosed spaces. The Acoustics Module of COMSOL Multiphysics has several tools to simulate the acoustics of rooms and other confined spaces. I will present those here.
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.
Report from the Joint CAA-ASA Acoustics Conference
Last month, the Acoustical Society of America (ASA) and the Canadian Acoustical Association (CAA) held the 21st joint meeting of the International Congress on Acoustics (ICA) in Montreal, Canada. This joint congress is one of the major acoustics conferences of 2013, featuring a range of parallel sessions that covered most topics in acoustics. These included, among other things, psycho acoustics, underwater acoustics, transducer modeling, acoustics of musical instruments, nonlinear acoustics, and many more. This year’s acoustics conference also featured a […]
Modeling Acoustic Damping Processes
Mufflers are often located in exhaust systems or on heat, ventilation, and air conditioning (HVAC) systems, where their key functionality is to dampen the noise that is emitted from the system. A correct description of the acoustic damping (absorption and attenuation) processes in the muffler is important when designing and modeling these systems.
Acoustofluidic Multiphysics Problem: Microparticle Acoustophoresis
The use of acoustic waves to manipulate suspensions of particles, such as cells, has inspired the work of many researchers, paving the way for the field of ultrasound acoustofluidics. The manipulation is achieved in many ways, including using bulk acoustic waves (BAW) and surface acoustic waves (SAW), as well as acoustic radiation forces and acoustic streaming-induced drag. The latter two combine to produce the acoustophoretic motion of the suspended particles; i.e., movement by means of sound, and the methods provide […]
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