Investigation of Mean-Flow Effects on Tubular Combustion Chamber Thermoacoustics Using a Burner Transfer Matrix Approach - new
A. Andreini, B. Facchini, A. Innocenti, D. Pampaloni
University of Florence, Florence, Italy
The paper presents a methodology to account for local mean-flow effects on thermo-acoustic instabilities to improve typical calculations performed under the zero-Mach number assumption. A 3D FEM model of a simplified combustor is solved with COMSOL Multiphysics® Pressure Acoustics interface. The Helmholtz equation is used to model the combustor and the classical k-τ model for the Flame Transfer ...
E. Lacatus, G. C. Alecu, A. Tudor, M. A. Sopronyi
Polytechnic University of Bucharest, Bucharest, Romania
Student-Polytechnic University of Bucharest, Bucharest, Romania
INFLPR -National Institute for Laser Plasma and Radiation Physics, Bucharest, Romania
Vibration and music therapies are non-invasive treatments having effective results although their basics are still disputed. By the application of COMSOL Multiphysics® software for modeling and analysis, some of the nonlinear physical phenomena laying on these applications may be clarified. Acoustic environmental stimuli at different intensities are continuously interacting with our bodies, ...
Finite Element Model for Simulating the Inspection of Steel Tubes Using Electromagnetic Acoustic Transducers - new
P. Sun, X. Ding, X. Wu, M. Cong
School of Mechanical Science & Engineering, Huazhong University of Science and Technology, Wuhan, China
Steel tubes are widely used in industries. In order to ensure the safety and reliability of industrial processes, electromagnetic acoustic transducers (EMATs) based guided wave technology has been developed for inspecting stainless steel tubes regularly. Theoretical models and finite element modes have been built to investigate the EMAT technology. However, existing models mainly focused on ...
L. Fromme , J. Waßmuth , D. Wehmeier ,
 Bielefeld University of Applied Sciences, Bielefeld, Germany
The knowledge of the acoustical transfer paths in active noise control systems is very important for the performance of the system. Unfortunately, simulation is challenging since even simple configurations require comprehensive experience in physics and modeling. Two test setups were chosen for basic investigations on modeling, simulation and validation. The first results presented here are ...
JBL Professional, Northridge, CA, USA
The author presents an overview of methods to build virtual prototypes of both horns and loudspeaker drivers which allows a significant reduction in the number of physical prototypes, as well as reduced development time. This paper will present some of the practical results from work the author has performed in the course of designing both transducers and horns using COMSOL Evolution of the ...
T. H. Hanley, H. T. D. Grigg, B. J. Gallacher
Newcastle University, Newcastle-Upon-Tyne, UK
Introducing a disorder into a finite periodic oscillatory system induces the presence of a 'trapped mode': a mode in which the displacement field is localised to the region of the disorder. A main inhibitor to MEMS resonators achieving a high quality (Q) factor is energy radiation through the support to the substrate. The trapped modes present a way to tune this to a minimal value. An initial ...
Finite Element Analysis into Eigenfrequencies of a Total Hip Stem with Different Levels of Loosening
T. Bender , M. Sass , W. Mittelmeier , R. Bader , D. Kluess 
 Department of Orthopaedics Research Laboratory for Biomechanics & Implant Technology, University Medicine Rostock, Rostock, Germany
A finite element model of a total hip replacement (THR) has been developed from the approach of modal analysis. The model is capable of determining the first 15 Eigenmodes of a THR with an artificial bone model. The model was equipped with several different defects to simulate a loosening of THR and to enforce a shifting of the frequency spectrum of the system’s Eigenfrequencies. Using the ...
G. Rosi, L. Teresi, A. DiCarlo, and F. dell'Isola
LaMS - Università degli Studi Roma Tre, Roma, Italy
Università degli Studi di Roma "La Sapienza", Roma, Italy
Liquid crystals - as all liquids - are generally modelled as incompressible media. In fact, mass-density changes occurring in these mesophases are minuscule and inconsequential in most regimes of interest. However, liquid crystals exhibit also phenomena that call for a more refined theory. In particular, it is experimentally well established that the Fréedericksz transition - i.e., the sudden ...
Y.F. Wang, Y.S. Wang, L. Wang
Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing, China
Department of Mechanical Engineering, Østfold University College, Halden, Norway
We show in this paper that by careful design of the geometry of the resonators, complete bandgap with relatively low center frequency can be obtained for 2D and 3D Phononic Crystals with resonators. The generation of the bandgap is due to the local resonance of the unit cell. Spring-mass and spring-pendulum models are developed to predict the boundaries of the complete bandgap. The predicted ...
SRM University & BITS Pilani University, Chennai, Tamil Nadu, India
Vibration analysis of perforated plates is extremely important when designing structures where resonance is the possible mode of failure. This paper deals with the vibration analysis of rectangular perforated plates with three different types of perforations. Vibration analysis is to be carried out by both COMSOL Multiphysics® Software and Experimental set-up. The applications of perforated ...