Acoustics

The field of acoustics is diverse and so is the need for computational tools supporting it.  Veryst provides acoustic simulation expertise in applications including room acoustics, miniature speakers, musical instruments, MEMS acoustic sensors and actuators, medical devices, and nondestructive testing.  We also help clients with noise reduction in automotive applications, rotating machinery, and turbulent flow.  We assist engineers with valuable and timely design insights that help optimize their products and evaluate new design concepts.  We also have in-house acoustic testing and vibration testing capabilities, which help identify sources of noise/vibration and how to mitigate them.

In many cases, the acoustic problem cannot be solved in isolation from other physics, specifically structural, fluid, electric, and heat transfer.  This multiphysics coupling between acoustics and other phenomena additionally becomes more significant as the devices get smaller.

Veryst is experienced in a wide range of acoustic simulations, including acoustic tissue heating, pressure acoustics, acoustophoresis, aeroacoustics, linearized Navier-Stokes, thermoviscous acoustics, and ray acoustics for high frequency acoustic simulations.

The first example here involves a lab-on-a-chip device for bodily fluids based on acoustophoresis.  This involves the motion of particles resulting from an oscillatory acoustic field.  This particular model, developed using COMSOL Multiphysics, involves pressure acoustics, solid mechanics, electric field, fluid flow, and particle tracing.  Geometry and particle properties used in this example are taken from available literature.  Figure 1 shows the particle distribution across the channel, demonstrating effective particle focusing toward the channel center.  The computational model helps designers select the dimensions, materials, operating frequency, and flow rate of the device.

Acoustics Piezoelectric Actuator
Figure 1. Acoustophoretic particle focusing in a microchannel, as well as deformation and von Mises stress in the device

A second example demonstrates Veryst’s acoustic simulation expertise in applications involving thermal ablation driven by an acoustic pressure source, which has considerable potential for the treatment of certain types of diseased tissue.  Using COMSOL Multiphysics, Veryst designed a catheter ablation system with an array of piezoelectric acoustic transducers.  The catheter system included a hollow central shaft to allow for a cooling fluid to circulate through the device.  We modeled the acoustic pressure field from the piezoelectric actuators (Figure 2) and used the results to specify a heat source in a bioheat transfer analysis to predict the temperature in the tissue.  Veryst evaluated several changes to the geometry and operating parameters of the ablation device, and predicted their effect on the efficacy of tissue damage.  Click here to learn more about Veryst’s work designing and simulating a catheter-based acoustic ablation device.

 

Acoustics Ablation Fig3
Figure 2. Plot showing pressure in the due resulting from the acoustic ablation device

The third example here addresses how immersion in a fluid affects the harmonic response of structures, whether they are micro-scale structures such as MEMS actuators or larger structures such as ships.  In this example, Veryst developed a coupled acoustic-structure eigenvalue analysis in COMSOL Multiphysics to determine the natural frequencies and mode shapes of a cantilever beam immersed in water, shown in Figure 3.  In this case, the beam size is large enough such that thermoviscous losses are negligible.  Click here to learn more about immersed beam vibrations.

Immersed Beam--animation1
Figure 3. Animation showing the fourth mode of deformation for a beam immersed in water

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Design and Simulation of a Catheter-Based Acoustic Ablation Device

Thermal ablation is a minimally invasive way to treat tumors, and simulating the physics of ablation can help in the design of ablation devices. Veryst designed and simulated a catheter-based acoustic ablation device relying on acoustic pressure waves to heat tissue to induce necrosis.

Guest editorial in COMSOL News 2017 Acoustics Edition

July 7, 2017
Dr. Nagi Elabbasi has a guest editorial article in COMSOL News 2017 Acoustics Edition. The article is titled “How Computational Acoustics Benefits from Multiphysics” and discusses some of the developments and challenges in acoustic simulation

Acoustics panel moderator

October 3, 2018
Dr. Elabbasi moderated a panel discussion on “Modeling Strategies for Acoustics Simulations” at COMSOL Conference 2018 Boston.  The panel discussed the use of different modeling strategies depending on the frequency range, model size, and details included in the physics used. 

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