Technical Papers and Presentations

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.

3D Acoustic Streaming Field in High-Intensity Discharge Lamps

B. Baumann[1], J. Schwieger[1], M. Wolff[1], F. Manders[2], J. Suijker[2]
[1]Hamburg University of Applied Sciences, Hamburg, Germany
[2]Philips Lighting, Turnhout, Belgium

High-intensity discharge lamps will in the foreseeable future be important light sources despite a growing market share of LEDs. Cost and energy efficient high frequency (300 kHz) operation is hampered by the excitation of acoustic resonances inside the arc tube, which results in low frequency (10 Hz) light flicker. Our aim is to calculate the acoustic streaming velocity field, which is related ...

Analyzing Muffler Performance Using the Transfer Matrix Method 

K. Andersen
Dinex Emission Technology A/S, Middelfart, Denmark

Exhaust noise must meet legislation targets, customer expectations and cost reduction which call for design optimization of the exhaust systems in the design phase. One solution is to use 3 dimensional linear pressure acoustics and calculate the transfer matrix of the muffler. The transfer matrix is the basis for calculating either the insertion loss or transmission loss of a muffler. The 3D ...

An Investigation of Loudspeaker Simulation Efficiency and Accuracy Using i) A Conventional Model, ii) The Near-To-Far-Field Transformation and iii) The Rayleigh Integral

R. Christensen[1], U. Skov[1]
[1] iCapture ApS, Roskilde, Denmark

Simulation on loudspeaker drivers require a conventional fully coupled vibro-acoustic model to capture all effect. An accurate vibroacoustic model can be time-consuming to solve, especially in 3D. In practical applications, this results in poor efficiency concerning the decision-making process to move on to the next simulation model. To overcome this the loudspeaker designer can use either the ...

Modeling Scattering from Rough Poroelastic Surfaces Using COMSOL Multiphysics®

A. Bonomo[1], M. Isakson[1]
[1]Applied Research Laboratories, The University of Texas at Austin, Austin, TX, USA

COMSOL Multiphysics® is used to address the problem of acoustic scattering from one-dimensional rough poroelastic surfaces. The poroelastic sediment is modeled following the Biot-Stoll formulation. The rough surfaces are generated using a modified power law spectrum. Both monostatic and bistatic scattering strengths are calculated. These results are compared with more conventional scattering ...

Numerical Modelling of Wave Propagation in Particulate Composites

P. S. K. Mylavarapu, and S. Boddapati
Defence Metallurgical Research Laboratory

Syntactic foams are hollow particle filled composites that have recently emerged as attractive materials for use in advanced structural applications in aerospace and defence industry. Ultrasonic characterization of these foams is performed extensively in order to understand the effect of porosity and particle size on the ultrasonic properties such as longitudinal velocity and attenuation. ...

Effects of Fluid and Structural Forces on the Dynamic Performance of High Speed Rotating Impellers.

C. Thiagarajan[1], G. Shenoy[2], B. S. Shenoy[3]
[1]ATOA Scientific Technologies Pvt Ltd, Whitefield, Bangalore, India.
[2]Department of Mechanical & Manufacturing Engineering, Manipal Institute of technology, Manipal, India
[3]Department of Aeronautical & Automobile Engineering, Manipal Institute of Technology, Manipal, India

Vibration and Dynamic performances of the rotating machinery are conventionally evaluated based on the dominant structural forces such as the centrifugal forces. The increase in rotational speed, miniaturization and performance, demands for improved and accurate evaluation of the vibration performance. The inclusion of coupled effects of fluid and centrifugal forces can contribute significantly ...

Modelling and Analysis of Acoustic Emissions and Structural Vibration in a Wind Turbine

B. Marmo, and B. Carruthers
Reactec Ltd., Edinburgh, United Kingdom

The onshore wind turbine industry must overcome many technical, commercial, and environmental difficulties. A significant element for planning consent is operational noise. Acoustic limits are strictly enforced and can lead to near-neighbour complaints as well as contractual disputes. Reactec have diagnosed, analysed and solved a problematic tonal resonance for a major wind turbine generator ...

Multiphysics Modelling of Sound Absorption in Rigid Porous Media Based on Periodic Representations of Their Microstructural Geometry

T.G. Zielinski[1]
[1]Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland

Sound absorption in porous materials with rigid frame and open porosity can be very effectively estimated by applying the Johnson-Allard model in order to substitute a porous medium with an equivalent effective fluid and then utilise the Helmholtz equation for time-harmonic acoustics. The model uses several parameters which characterize the micro-geometry of porous material from the macroscopic ...

Development of a Reactive Silencer for Turbo Compressors

J. Smeulers[1], N. Gonzalez Diez[1]
[1]TNO, Delft, The Netherlands

Turbo compressors can generate high frequency tonal noise, causing nuisance in the environment. As the noise is radiated from the piping, a silencer is installed between the compressor and the pipe system. Commonly an absorption silencer is applied, which is a vessel that contains acoustic absorption material. Due to high flow velocities and vibrations the absorption material may be blown out of ...

Nondestructive Testing of Composites Using Model Based Design

E. Nesvijski[1]
[1]ACOUSTICS@MBD CONSULTANTS, LLC, Westborough, MA, USA

There is a practical interest among composite materials manufacturers to high-speed accurate non-destructive evaluation (NDE) technology for voids inspection when these voids are natural components of such complex structures like resin insulated layer of double-sided copper-clad laminates. Model based design (MBD) of NDE system is one of principal solutions for voids inspection in such composites ...

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