A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Tosun, Nail
Ceylan, Doga
Polat, Hakan
Keysan, Ozan
The analysis of the velocity skin effect (VSE) in electromagnetic launchers (EMLs) requires a 3-D transient finite element method, unlike magnetic skin and proximity effects. However, VSE is dominant at high speeds, and this creates convergence problems when moving or deformed mesh physics is used in a transient FEM in the 3-D analysis. Commercial finite element software cannot solve the electromagnetic aspects of such a high-speed application with a transient solver in 3-D. Although 2-D approximations can be used, such an approximation overestimates VSE resistance due to geometry simplifications. In this study, we proposed a novel quasi-transient 3-D FEM model where the air-armature region's conductivity is varied to emulate the high-speed motion of the armature. Results showed that the 2-D approximation overestimates the VSE resistance by almost 40%. The proposed VSE model has been included in the EML model, and simulation results are compared for experimental results with different EMLs, EMFY-1, and EMFY-2 and showed good agreement.


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Kuzuoğlu, Mustafa (2017-07-14)
Electromagnetic scattering from rough surfaces is modeled by combining the periodic finite element method and the transformation electromagnetics approach. The behavior of the radar cross section (RCS) at both specular and backscattering directions is analyzed as a function of rms height and correlation length with the help of Monte Carlo simulations. The concept of backscattering enhancement is illustrated, and some conclusions are drawn about the RCS statistics.
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ÖZGÜN, ÖZLEM; Mittra, Raj; Kuzuoğlu, Mustafa (2020-01-01)
In this article, a hybrid numerical method, called finite element method (FEM) + dipole moment (DM), is presented for efficient solution of multiscale electromagnetic radiation and scattering problems that involve structures with fine features, such as thin-wire antennas or objects. In this method, the FEM is hybridized with the DM approach to help ease certain computational burdens, such as mesh refinement, ill-conditioning, memory overload, and long computation times, when solving multiscale problems with...
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Aşırım, Özüm Emre; Kuzuoğlu, Mustafa; Özgün, Özlem; Department of Electrical and Electronics Engineering (2013)
This thesis analyzes the problem of electromagnetic wave scattering from rough surfaces using finite element method. Concepts like mesh generation and random rough surface generation will be discussed firstly. Then the fundamental concepts of the finite element method which are the functional form of a given partial differential equation, implementation of the element coefficient matrices, and the assemblage of elements will be discussed in detail. The rough surface and the overall mesh geometry will be imp...
A coordinate transformation approach for efficient repeated solution of Helmholtz equation pertaining to obstacle scattering by shape deformations
Ozgun, Ozlem; Kuzuoğlu, Mustafa (2014-06-01)
A computational model is developed for efficient solutions of electromagnetic scattering from obstacles having random surface deformations or irregularities (such as roughness or randomly-positioned bump on the surface), by combining the Monte Carlo method with the principles of transformation electromagnetics in the context of finite element method. In conventional implementation of the Monte Carlo technique in such problems, a set of random rough surfaces is defined from a given probability distribution; ...
Comparative study on surface enhanced raman scattering activity of various silver nanostructures
Demirtaş, Özge; Bek, Alpan; Taşgın, Mehmet Emre; Department of Physics (2017)
In this work, the effect of the strong field enhancement generated in the near field of metal nanoparticles and nanowires was investigated by taking advantage of the plasmon frequencies induced by Raman laser light stimulation of free conduction electrons of these metal nanostructures. Small number of molecules that are either bound to these nanostructures or located up to a few nanometers away from the nanostructures can be detected easily through strong electromagnetic field enhancement. The aim of this w...
Citation Formats
N. Tosun, D. Ceylan, H. Polat, and O. Keysan, “A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods,” IEEE TRANSACTIONS ON PLASMA SCIENCE, pp. 1500–1507, 2021, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/90369.