Here you will find presentations given at COMSOL Conferences around the globe. The presentations explore the innovative research and products designed by your peers using COMSOL Multiphysics. Research topics span a wide array of industries and application areas, including the electrical, mechanical, fluid, and chemical disciplines. Use the Quick Search to find presentations pertaining to your application area.

Analysis of a Plasma-Mediated Photoacoustic Response From Plasmonic Nanoparticles in Ultrashort Regime

A. Hatef [1], B. Darvish [1], A. Dagallier [2], C. Boutopoulos [2], M. Meunier [2],
[1] Nipissing University, North Bay, ON, Canada
[2] École Polytechnique de Montréal, Montréal, QC, Canada

Over the last decade, plasmonic nanoparticles (PNPs) have received growing interest as exogenous contrast agents in the thermal expansion based photoacoustic (PA) imaging technique in biomedical applications [1]. Such functionality is due to the localized surface plasmon resonance (LSPR) created by the light-induced coherent oscillation of the conduction electrons in the PNPs. In the near-field ...

The Effect of Resistance on Rocket Injector Acoustics

C. J. Morgan [1], S. R. Fischbach [1],
[1] Jacobs ESSSA Group, NASA Marshall Space Flight Center, Huntsville, AL, USA

This study evaluates the effect of injector resistance on the mode shapes and complex eigenfrequencies of an injector/combustion chamber system by defining a high Mach-flow, potential flow form of the convective wave equation in the Coefficient Form PDE Mathematics interface. Background steady-state flow conditions are determined through a NASA Marshall Space Flight Center in-house fluid ...

Friction Factor for Perforated Pipes

D. Neihguk [1], M. L. Munjal [2], A. Prasad [1],
[1] Mahindra & Mahindra Ltd, Chennai, India
[2] Indian Institute of Science, Bangalore, India

Perforated pipes are extensively used to control exhaust noise in automobiles [1-4]. The energy loss associated with the perforations leads to back pressure which needs to be quantified and minimized [5]. An objective approach presented in [6] is the introduction of friction factor for perforated ducts as a function of the porosity. In this article, the utilization of the CFD Module of COMSOL ...

Improving the Performance of Hearing Aids Using Acoustic Simulations

Mads Jakob Herring Jensen
Dr., Widex A/S, Denmark

In modern hearing aids, the performance of directional microphone systems is dependent on both the acoustics around thehearing aid and on the specific signal processing algorithms. The sound pressure at the microphone inlets depends on microphone location in the hearing-aid shell, the inlet shape, and on the placement of the hearing aid on the head of the user. In the present work, the ...

Finite Element Modeling of Ultrasonic Transducers for Polymer Characterization

S. De Paolis[1], F. Lionetto[1], and A. Maffezzoli[1]

[1]Department of Innovation Engineering, University of Salento, Lecce, Italy

Finite element analysis has been used to model the ultrasonic wave propagation both in a custom made transducer and in the tested polymer sample. The model consists of acoustic (passive elements) and electroacoustic (active elements) transmission lines. The simulation of the acoustic propagation accounts for the interaction between the transducer and the materials in the buffer rods, and the ...

Study of an Electroacoustic Absorber

A-S. Moreau[1], H. Lissek[1], and R. Boulandet[1]
[1]EPFL-STI-IEL-LEMA, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

In this paper, the underlying concept of electroacoustic absorbers is studied with the help of Comsol Multiphysics® Acoustics Module. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face, there is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impedance that the transducer's membrane presents ...

Guided Wave in Engineering Structures Using Non-Contact Electromagnetic Acoustic Transducers: A Numerical Approach for the Technique Optimisation

S. Soua[1], A. Raude[1], and T-H. Gan[1]
[1]NDT Technology Group, TWI Ltd, Cambridge, United Kingdom

There are over 10 million kilometers of pipes and pipelines around the world that carry hazardous fluids and gases. Fluids include oil, oil products, chemicals such as solvents, caustics, acids, corrosives and combustibles often at high pressure and temperature. These pipes are susceptible to corrosion if they are not protected properly by the environment or the contents. Inspection of pipes is ...

Modeling the response of photoacoustic gas sensors

S.L. Firebaugh[1], F. Roignant[2], and E.A. Terray[3]

[1]United States Naval Academy, Annapolis, Maryland, USA
[2]Polytechnique Nantes, Nantes, France
[3]Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

A fast, high-sensitivity detector is required for studies of environmentally relevant gases. Photoacoustic spectroscopy (PAS), an absorption spectroscopy technique in which absorption is detected as sound, is explored as a possible solution. A tuning-fork based PAS sensor is modeled using COMSOL. The model combines the acoustic and piezoelectric modules and also includes viscous damping. The ...

FEM Simulation of Generation of Bulk Acoustic Waves and their Effects in SAW Devices

A.K. Namdeo[1], N. Ramakrishnan[2], and H.B. Nemade[1]
[1]Department of Electronics and Communication Engineering, Indian Institute of Technology Guwahati, Guwahati, India
[2]Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, India

This paper presents finite element method (FEM) simulation study of the generation of bulk acoustic waves (BAWs) and their effect on the performance of surface acoustic wave (SAW) devices, using COMSOL Multiphysics. A SAW delay line structure using YZ-cut lithium niobate substrate is simulated. The radiation of the bulk waves in all angles into the interior of the substrate is analyzed. The bulk ...

Effects Of The Microstructure Of Fibrous Media On Their Acoustic Properties

C. Peyrega, and D. Jeulin
Center of Mathematical Morphology, Mines ParisTech, Fontainebleau, France

This study is a part of the Silent Wall ANR project, to which the Center of Mathematical Morphology is associated. Its main objective is to build an acoustical and thermal insulating system for buildings, composed of fibrous materials. The material is composed of two phases: the fibrous network and the air surrounding it. At the microscopic scale the absorption of the acoustic wave is mainly ...