A. Weddemann, J. Jadidian, S. Khushrushahi, Y. Kim, and M. Zahn
Research Laboratory of Electronics
Massachusetts Institute of Technology
The modeling of ferromagnetic materials is a challenging task of high industrial and academic impact. Thin film and granular systems form the basis of novel spintronic devices such as modern hard drives with a high data area storage density. In order to push the current limits even further and to design more efficient devices, a strong understanding of the governing dynamics is required. We ...
The Transient Modeling of Single-Bubble Nucleate Boiling in a Sub-Cooled Liquid Using an ALE Moving Mesh
C. J. Forster, and M. K. Smith
Georgia Institute of Technology
This paper investigates the evolution of a single bubble going through growth, pinch-off, and condensation while rising due to buoyancy forces in a sub-cooled liquid. Phase change is modeled on the evolving liquid-vapor interface by considering changes in enthalpy and heat fluxes at the interface. A comparison of the ALE model is made with the same single-bubble system computed with a level-set ...
L. Desgrosseilliers, and D. Groulx
A cornerstone of Chemical and Mechanical Engineering undergraduate programs the world over is the experimental and theoretical study of heat exchange. Graduating engineering students gain some appreciation in their lab course by comparing empirical correlations combined with the thermodynamics of heat exchange with the real operation of a counter-current, double pipe, single-phase heat exchanger.
M. Gobbert, and D. Trott
University of Maryland Baltimore County
Many application problems have non-smooth forcing terms, such as the Dirac delta function. The convergence order for the FEM solution is limited by the regularity of the solution in this case. This paper presents information on the techniques needed in COMSOL 4 to enable FEM convergence studies for time-dependent problems of this type, including how to correctly implement the Dirac delta ...
S. Ni, C. Yang Koh, S. Kooi, and E. Thomas
Institute for Soldier Nanotechnologies
Dept. of Materials Science and Eng.
Recently, the concepts of fractal geometry have been introduced into electromagnetic and plasmonic metamaterials. With their self-similarity, structures based on fractal geometry should exhibit multi-band character with high Q factors due to the scaling law. However, there exist few studies of phononic metamaterials having fractal geometry. COMSOL is used to investigate vector elastic and ...
Using the Superposition Principle and Edge Current Model to Compute Impedance of the Coil in a Logging Tool
T. Zhao, G. Minerbo, J. Hunka, and G. Hazen
Sugar Land, TX
Coil antenna is the simplest form in well-logging tools for resistivity measurement of the formation. This paper introduces how to accurately compute the impedance of the coil with very thin wires at high frequency, and with the complex borehole structure, e.g., metal housing and collar. A 3D RF electromagnetic wave in frequency domain is used. An alternate array of transmitters and receivers ...
J. Raj, S. Birla, K. Pitchai, J. Subbiah, and D. Jones
Indian Institute of Crop Processing Technology, Thanjavur, Tamil Nadu, India
Dept. of Biological Systems Engineering, University of Nebraska Lincoln, Lincoln, NE
Dept. of Food-Science, University of Nebraska Lincoln, Lincoln, NE
Domestic microwave ovens are notorious for their uneven heating of food materials. This is caused by a varying electromagnetic field whose variation is caused by a number of factors dependent on the oven and the food parameters. Experimental validation of heating would therefore give highly variable results and would be labour, resource and time intensive. Thus modeling of the microwave ...
A.Weddemann, D. Kappe, and A. Hütten
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA, USA
Department of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, Bielefeld, Germany
In principal, the calculation of the magnetic state inside a magnetic object requires the evaluation of the field in the entire unbounded space. With finite element methods restricted to finite domains, commonly auxiliary domains are employed which result in a non-physical cut-off. Not only are these additional domains result in an increased number of degrees of freedom which are strictly ...
Optimization of Design Parameters of a Novel MEMS Strain Sensor used for Structural Health Monitoring of Highway Bridges
H. Saboonchi, and D. Ozevin
Civil Engineering Department
University of Illinois at Chicago
The novel Micro Electro Mechanical System (MEMS) based Piezoresistive stain sensor is presented in this paper. The main goal of this sensor is to monitor the localized strain in the highway bridges especially near the crack tips. Monitoring the crack growth on the bridges can lead to early detection and prevention of bridge failures. The COMSOL Multiphysics software was used to optimize the ...
Simulation of Dendritic Solidification in Cubic and HCP Crystals by Cellular Automaton and Phase-Field Models
M. A. Zaeem, H. Yin, and S. D. Felicelli
Center for Advanced Vehicular Systems, Mississippi State University, MS
Oak Ridge National Laboratory, TN
Mechanical Engineering Department, Mississippi State University, MS
A cellular automaton (CA)-finite element (FE) model and a phase field (PF)-FE model were used to simulate equiaxed dendritic growth during solidification of cubic and hexagonal crystals. The governing equations of PF model include three coupled partial differential equations (PDE) for evolution of concentration, temperature, and non-conserved PF variable. These PDEs were solved using the ...