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.


A Numerical Model for Investigating the Effect of Rough Surface Parameters on Radar Cross Section Statistics
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.
Multiscale Modeling of Thin-Wire Coupling Problems Using Hybridization of Finite Element and Dipole Moment Methods and GPU Acceleration
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...
Investigation of rough surface scattering of electromagnetic waves using finite element method
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; ...
Two dimensional modeling of electromagnetic radiation and scattering by spectral element method
Mahariq, İbrahim; Tarman, Işık Hakan; Kuzuoğlu, Mustafa; Department of Engineering Sciences (2014)
In this thesis, the spectral element method is utilized in numerical modeling of two-dimensional, frequency-domain electromagnetic scattering and radiation problems. We perform domain truncation by the well-known perfectly matched layer (PML) and provide the corresponding formulation. The attenuation factor associated with the PML formulation is optimized so that the best accuracy is achieved for a wide range of Gauss- Legendre -Lobatto grids per wavelength. The optimality of the provided attenuation factor...
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.