How to Use Dispersion Curves to Analyze Fluid-Filled Pipes

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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Caty Fairclough November 7, 2017

From cocktail parties to public transit, there are competing sound sources in many everyday environments. If you want to listen to one specific sound, say a friend’s question, in a complex auditory setting, you have to distinguish between the sounds around you and focus on the one of interest. This situation is known as “the cocktail party problem”. Understanding how humans solve this problem can lead to advancements in hearing aid designs.

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Caty Fairclough November 1, 2017

You’re listening to music when you bump into your loudspeaker, knocking it off the table. Fortunately, it still works! In his keynote presentation at the COMSOL Conference 2017 Boston, Richard Little discussed how Sonos, Inc. ensures that loudspeakers are durable enough to withstand certain stresses and how they use simulation to improve the robustness of the transducer component. If you missed his talk, you can watch the video recording below, followed by a quick summary of his presentation.

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Brianne Costa October 31, 2017

My favorite novel to read around the Halloween season is Stephen King’s It. A common misconception about the book is that “It” is just a scary clown — It is actually the embodiment of whatever you fear most. If what scares you the most is the possibility of ghosts, don’t worry: a researcher used acoustics analysis to explain that whatever scares you this Halloween, like It, is just a trick of the mind (and vibroacoustic effects…)

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Guest Linus Fagerberg October 3, 2017

Guest blogger Linus Fagerberg from Lightness by Design picks up where he left off in his previous blog post to discuss how radiated sound depends on the shell thickness of a muffler. Here, we discuss different entities for gauging the performance of mufflers. One important parameter is the thickness of the muffler’s casing and how this affects its performance. By performing acoustic-structure interaction simulations, we can see how shell thickness affects muffler performance.

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Guest Linus Fagerberg September 14, 2017

Guest blogger Linus Fagerberg from Lightness by Design returns to share a novel approach for predicting external noise generation in muffler designs. In recent years, the European Union has introduced stricter noise emission limits for road vehicles. For those designing mufflers, these limits make it important to create more efficient ways of developing and assessing the performance of their designs. At Lightness by Design, we’ve developed a novel approach that accomplishes this goal.

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Guest Thomas Clavet August 31, 2017

Today, guest blogger Thomas Clavet of EMC3 Consulting, a COMSOL Certified Consultant, discusses simulating phased array and geometrically focused probes. Ultrasound focusing is widely used in various industrial applications, such as nondestructive testing (NDT) and medical imaging. For clinical applications, high-intensity focused ultrasound (HIFU) is a specific aspect of this technology where most of the power provided by the probe is carried to a targeted zone to coagulate biological tissues. This blog post discusses ultrasound focusing simulation.

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Brianne Costa August 25, 2017

A leading cause of smog and particulate pollution is the harmful emissions from automobiles, especially those that run on diesel engines. Today, most vehicles with diesel engines are required to install a diesel particulate filter (DPF) to catch carbon-based particulates that are emitted from their exhaust. Using the COMSOL Multiphysics® software, we can analyze the acoustics of a DPF.

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Caty Fairclough July 31, 2017

One application of acoustic streaming (AS), the process of using sound waves to generate steady fluid motion, is adjusting grain morphology during the metal solidification process. Since ensuring the best product possible is key, engineers in the metal processing industry must improve AS, which can require costly field tests and test rigs. To see if simulation can be used to reduce this need, researchers analyzed AS treatment with the COMSOL Multiphysics® software.

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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.

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Bridget Cunningham July 10, 2017

Of the 72 million potential hearing aid users around the world, each needs a device fitted to meet their needs. In-the-ear measurements are performed to ensure both comfort and effectiveness. These measurements require the use of a microphone — the size of which can cause issues. The device can be too large to fit into the measured sound field. Alternatively, it can be too big compared to the wavelength and disturb the acoustic field. One solution is a probe tube…

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