## How to Use the Boundary Element Method in Acoustics Modeling

##### 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.

Weiterlesen##### Mads Herring Jensen July 25, 2017

Detailed modeling of the complex interaction of flow and acoustics is achieved in the COMSOL Multiphysics® software and add-on Acoustics Module using the linearized Navier-Stokes interfaces. With the release of version 5.3, the capabilities were further extended with the addition of a new stabilization scheme. This allows robust simulations of systems with acoustic properties that are modified by or depend on a turbulent background flow; e.g., automotive exhaust systems. Here, we introduce important modeling concepts and present application examples.

Weiterlesen##### Mads Herring Jensen January 26, 2017

Modeling acoustically large problems requires a memory-efficient approach like the discontinuous Galerkin method. To make solving these types of problems easier, we’ve added a new physics interface based on this method to the Acoustics Module: the Convected Wave Equation, Time Explicit interface. It can include a stationary background flow and is suited for modeling linear ultrasound applications. Today, we will explore how to use this interface with the example of an ultrasound flow meter.

Weiterlesen##### Mads Herring Jensen January 21, 2016

COMSOL Multiphysics version 5.2 introduced a number of new features and functionality, including an acoustics-specific plot type called the Octave Band plot. This plot type provides you with an easy and flexible way to represent any frequency response, transfer function, sensitivity curve, transmission loss, or insertion loss — all of which are essential plots in many acoustics applications. Let’s learn a bit more about the Octave Band plot, while highlighting its various options and settings.

Weiterlesen##### Mads Herring Jensen October 1, 2015

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.

Weiterlesen##### Mads Herring Jensen February 25, 2015

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.

Weiterlesen##### Mads Herring Jensen February 28, 2014

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.

Weiterlesen##### Mads Herring Jensen February 27, 2014

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.

Weiterlesen##### Mads Herring Jensen January 2, 2014

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.

Weiterlesen##### Mads Herring Jensen July 8, 2013

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 […]

Weiterlesen##### Mads Herring Jensen May 23, 2013

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.

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