COMSOL Day: Acoustics
See what is possible with multiphysics modeling
Acoustics and vibrations are critical aspects in many industries, including those dealing with loudspeakers, microphones, mobile devices, hearing aids, building acoustics, car audio systems, ultrasound imaging, and nondestructive testing (NDT).
COMSOL Multiphysics® is widely recognized in the acoustics field for its ability to model all aspects of acoustics using physics-based models. This includes the modeling of microacoustics, room acoustics, aeroacoustics, ultrasound, vibroacoustics, and electroacoustics. The software offers multiphysics modeling capabilities as well as a variety of numerical methods for creating and solving high-fidelity models of these systems and devices.
Join us for COMSOL Day: Acoustics, a free, one-day online event where you will learn about the advantages of using multiphysics modeling in acoustics studies and design. There will be presentations by invited speakers from industry and COMSOL-led technical sessions that will include demonstrations within the software.
Acoustics and vibrations play an important role in many industries and applications, from handheld devices to large concert halls and factory settings.
The demand for better design and optimization of acoustic and soundproofing devices has risen, specifically for improved performance, device size and placement, aesthetics, and material type and cost.
COMSOL Multiphysics® is commonly used to model these devices because it makes it possible to couple acoustics with other physical phenomena, such as structural vibrations and electromagnetic forces, and uses state-of-the-art optimization techniques.
In this session, we will provide an overview of various acoustics challenges and highlight the specific COMSOL Multiphysics® features designed to address them. We'll also share our insights on future development trends for the software.
Jean-Marie Henault, EDF (Électricité de France)
Reinforced concrete structures can be inspected with different nondestructive evaluation (NDE) techniques, particularly with ultrasound techniques.
Ultrasound techniques are based on mechanical wave propagation. Considering the usual working frequencies, from several 10 kHz to a few MHz, and the wave velocity in concrete, the wavelength could be from a few centimeters to a few millimeters. Therefore, these techniques are affected by wave multiscattering by the aggregates of the material. Moreover, an additional attenuation could come from the mortar matrix.
Modeling the wave propagation in concrete structures and simulating different cases to better understand the inspection results, confirm the limitation of the actual techniques, and find ways to optimize the measuring conditions represents a challenging task.
In COMSOL Multiphysics®, the Solid Mechanics interface and discontinuous Galerkin method can be used to create 2D simulations. The user can easily define the geometry of the inspected piece, the materials (homogenized concrete or concrete composed by aggregates in a mortar matrix, steel elements, etc.), and the NDE device characteristics, like the wave polarization and emitting signal.
In this keynote talk, different use cases will be presented:
- Inspection of a reinforced concrete wall including defects (void, honeycomb, and delamination) with an ultrasound tomograph
- Wave-velocity gradient assessment with a multichannel analysis of surface waves (MASW) technique
- Inspection of a concrete–steel–concrete pipe with a pulse-echo technique
Acoustic propagation in rooms, halls, car cabins, and other enclosed yet definitive spaces falls within the field of room acoustics. COMSOL Multiphysics® has studies for both wave acoustics and ray acoustics that allow you to model room acoustics according to the wavelength–room length ratio. The COMSOL® software lets you combine these methods depending on the size and geometry.
This session will go over methods for determining the acoustic properties of rooms that include sound absorbers, diffusers, and systems.
Acoustic fields can induce a steady flow in a fluid, a phenomenon referred to as acoustic streaming. Acoustic streaming occurs due to nonlinear viscous stresses in either the fluid's viscous boundary layer or bulk or due to gradients in the fluid's material properties. This phenomenon can be utilized for mixing, improved heat transfer, and manipulating particle trajectories.
Modeling acoustic streaming requires accounting for nonlinear terms, making it more intricate than standard acoustic models. The recent addition of a multiphysics coupling for acoustic streaming in COMSOL Multiphysics® version 6.1 greatly simplifies formulating and solving these types of models.
Attend this session to learn how to model acoustic streaming and gain an understanding of the mechanisms behind boundary-driven, bulk-driven, and thermoacoustic streaming.
Henrik Bruus, Technical University of Denmark (DTU)
For the past two decades, COMSOL Multiphysics® has been a crucial component of the research carried out by Prof. Bruus' research group, the Theoretical Microfluidics Group at DTU. In this keynote talk, Prof. Bruus will present some of the latest results of the group's work on the fundamental physics of ultrasound waves in microfluidic systems, a field known as acoustofluidics, and its applications within cell handling in lab-on-a-chip systems. He will emphasize the closed feedback loop between theory, COMSOL® simulations, and experiments.
Learn the fundamental workflow of COMSOL Multiphysics®. This introductory demonstration will show you all of the key modeling steps, including geometry creation, setting up physics, meshing, solving, and postprocessing.
Anton Melnikov, Bosch Sensortec GmbH
Bianisotropic acoustic metagratings, recently proposed, offer opportunities for manipulating passive acoustic wavefronts, which is of particular interest in the development of flat acoustic lenses and ultra-high-frequency ultrasound imaging. Despite this, they have never been scaled to the MHz frequencies commonly used in ultrasound imaging due to the challenges of producing complex microscopic structures. A novel fabrication technique, two-photon polymerization, can now be used to manufacture subwavelength structures in this frequency range. However, shrinking the size leads to thermoviscous effects that reduce efficiency and cause a frequency downshift of the transmission peak.
In this study, we propose three microacoustic metagrating designs that refract a normally incident wave toward -35 degrees at 2 MHz. Our approach involves utilizing the thermoviscous acoustics physics available in the Acoustics Module and leveraging topology and shape optimization tools provided by the Optimization Module to create meta-atoms that are not affected by thermoviscous effects. Our experimental findings validate the accuracy of our numerical simulations, thereby verifying the efficacy of our designs.
When devices have geometric details with dimensions close to those of the thermal and viscous boundary layers, it becomes important to consider thermoviscous losses.
Thermoviscous losses are especially pronounced in structures with submillimeter features where acoustic propagation occurs, such as in components of handheld devices, loudspeaker grilles, earbuds, hearing aids, and perforates used in mufflers and for sound insulation.
With COMSOL Multiphysics®, you can easily model such devices by utilizing the software's built-in features for modeling thermoviscous losses. For multiphysics simulations, the losses can be included in vibroacoustic settings or transducer models, where electromechanical forces can be coupled. Additionally, there are integrated solutions available for combining with and coupling to lumped electroacoustic representations.
In this session, you will learn modeling techniques for capturing these effects, including how to set up multiphysics models. You will also get an introduction to modeling microacoustics systems that include nonlinear effects.
The modeling of ultrasonic wave propagation in both solids and fluids is a crucial aspect in the development of ultrasonic nondestructive testing (NDT) devices for structural health monitoring, inline/insertion flowmeters, clamp-on flowmeters, medical imaging, therapeutic ultrasound equipment, and more.
COMSOL Multiphysics® offers prebuilt features for analyzing ultrasonic wave propagation in elastic and piezoelectric solids as well as in quiescent and moving fluids in the time and frequency domains.
This session will provide an overview of the ultrasonic and NDT modeling and simulation capabilities in COMSOL Multiphysics®. We will delve into the fundamentals of wave propagation in solids and fluids and explore various applications of ultrasound technology, including piezoelectric transducers, conventional and guided wave NDT, ultrasound flowmeters, and medical ultrasound.
When analyzing the propagation of acoustic waves in moving fluids, it is essential to examine convective effects, reflection and refraction in flow gradients, and flow-induced noise. Applications for these types of analyses include mufflers, noise from jet engines, liners and grilles, and protrusions on bodies subjected to flow. COMSOL Multiphysics® features customized functionality for the modeling and simulation of aeroacoustics, including background flow. Furthermore, the software's capability to combine a large eddy simulation (LES) or detached eddy simulation (DES) with pressure acoustics enables the simulation of flow-induced noise.
In this session, you will learn how to model aeroacoustics effects, convected acoustics, and flow-induced noise in COMSOL Multiphysics®.
The performance of acoustic devices often requires user-defined objective functions, since it is difficult to predefine the goals for all possible applications of a device. Such goals can be defined using custom variables and expressions in COMSOL Multiphysics®.
During this session, we will showcase the optimization techniques and interfaces available in COMSOL Multiphysics® in the context of pressure acoustics, structural mechanics, and magnetic problems. The presentation will cover basic parameter optimization as well as shape and topology optimization.
Additionally, we will explain how parameter estimation can be used to convert experimental data to material data for improved accuracy. Finally, we will discuss how to evaluate and minimize a design's sensitivity to various design parameters that inherently bear uncertainty.
Accurately solving equations for acoustically large models requires the use of sophisticated numerical methods and solution algorithms.
COMSOL Multiphysics® offers several space discretization options, such as the finite element method (FEM), boundary element method (BEM), and discontinuous Galerkin methods, and the ability to combine these methods within one model. For example, the COMSOL® software can be used to couple elastic waves in solids with pressure acoustics in fluids using a hybrid FEM–BEM approach.
The software also provides a range of meshing and solution algorithms for optimal performance and efficient resource utilization in acoustic modeling, allowing users to minimize memory and CPU time.
In this session, we will show you the steps involved in optimizing solver settings for robust modeling of acoustic phenomena using COMSOL Multiphysics®. Starting with a predefined solver suggestion, you will learn how to make necessary adjustments to ensure accurate and efficient modeling results.
Designing and optimizing loudspeakers calls for multiphysics modeling. Depending on the required accuracy and complexity of the loudspeaker system, this modeling can be accomplished through various numerical methods. The capabilities of COMSOL Multiphysics® enable you to model everything from lumped electroacoustics models in the frequency domain to nonlinear transient analyses of total harmonic distortion. Furthermore, it includes efficient numerical methods and optimization algorithms that help you design components with superior performance.
In this session, you will see modeling techniques for simulating loudspeakers as well as the appropriate postprocessing features in COMSOL Multiphysics® that provide you with a fully virtual testing environment.
Register for COMSOL Day: Acoustics
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