scholarly journals Singularity Expansion Method for thin wires and the Method of Modal Parameters

2019 ◽  
Vol 17 ◽  
pp. 177-187
Author(s):  
Sergey V. Tkachenko ◽  
Juergen B. Nitsch ◽  
Felix Middelstaedt ◽  
Ronald Rambousky ◽  
Martin Schaarschmidt ◽  
...  
Keyword(s):  
Fourier Series ◽  
Numerical Investigation ◽  
Integral Equations ◽  
Expansion Method ◽  
Modal Parameters ◽  
Mixed Potential ◽  
Thin Wire ◽  
Circular Loop ◽  
Thin Wires ◽  
Good Agreement

Abstract. Here, we describe a technique to define the Singularity Expansion Method (SEM) poles for short-circuited thin-wire structures developed using the Method of Modal Parameters (MoMP). The MoMP method consists of in the expansion of the system of mixed-potential integral equations (MPIE) into the Fourier series, including the kernels containing Green's function. Corresponding equations for Fourier modes contain infinite matrices of p.u.l. inductance and capacitance, and the solution for current can be obtained using the infinity matrix of p.u.l. impedance. The SEM poles are given by the zeros of the determinant of this matrix. For the case of the symmetrical circular loop, this equation transforms to one well-know from the literature. Numerical investigation of solutions for the poles of the first layer has shown good agreement with previously obtained analytical and numerical results for different wire configurations.

scholarly journals A full wave description for thin wire structures with TLST and perturbation theory

2018 ◽  
Vol 16 ◽  
pp. 123-133
Author(s):  
Fabian Ossevorth ◽  
Ralf T. Jacobs ◽  
Hans Georg Krauthäuser
Keyword(s):  
Perturbation Theory ◽  
Closed Form ◽  
Current Distribution ◽  
Perturbation Approach ◽  
Mixed Potential ◽  
Thin Wire ◽  
Method Of Moment ◽  
Initial Current ◽  
Full Wave ◽  
Good Agreement

Abstract. A full wave description of a thin wire structure, that includes mutual interactions and radiation, can be obtained in closed form with the so-called Transmission Line Super Theory or a refined variant of this method that utilises perturbation theory. In either procedure, a set of mixed potential integral equations is solved for the currents that propagate along a wire. With the perturbation approach, no iteration is required to approximate the initial current distribution on the wire. This procedure will be applied to solve multi-wire problems. The theory will be derived and computed results will be shown to be in good agreement with method of moment computations.

On the Use of Nonsingular Kernels in Certain Integral Equations for Thin-Wire Circular-Loop Antennas

2008 ◽  
Vol 56 (1) ◽  
pp. 151-157 ◽  
Author(s):  
George Fikioris ◽  
Panagiotis J. Papakanellos ◽  
Hristos T. Anastassiu
Keyword(s):  
Integral Equations ◽  
Thin Wire ◽  
Circular Loop ◽  
Loop Antennas

scholarly journals Estimating Ruin Probability in an Insurance Risk Model with Stochastic Premium Income Based on the CFS Method

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 982
Author(s):  
Yujuan Huang ◽  
Jing Li ◽  
Hengyu Liu ◽  
Wenguang Yu
Keyword(s):  
Fourier Series ◽  
Ruin Probability ◽  
Risk Model ◽  
Expansion Method ◽  
Nonparametric Estimator ◽  
Insurance Risk ◽  
Numerical Examples ◽  
Complex Fourier Series ◽  
Premium Income ◽  
Insurance Risk Model

This paper considers the estimation of ruin probability in an insurance risk model with stochastic premium income. We first show that the ruin probability can be approximated by the complex Fourier series (CFS) expansion method. Then, we construct a nonparametric estimator of the ruin probability and analyze its convergence. Numerical examples are also provided to show the efficiency of our method when the sample size is finite.

Computational Investigation of Different Turbulent Models When Predicting Airflow in an Enclosure

2008 ◽  
Author(s):  
Xi Wang ◽  
Hassan Naji ◽  
Ahmed Mezrhab
Keyword(s):  
Numerical Investigation ◽  
Turbulence Models ◽  
Turbulent Stress ◽  
Computational Investigation ◽  
Isothermal Case ◽  
The Mean ◽  
Turbulent Models ◽  
Rsm Model ◽  
Cold Case ◽  
Good Agreement

In the present study, a numerical investigation is carried out for an isothermal case, a hot case and a cold case with FLUENT code. Three turbulence models are considered: the k-ε realisable model, the RNG k-ε model and the RSM linear model. The obtained results are compared to experiments and show generally a good agreement for the mean velocities and temperatures, but less satisfactory for the turbulent stress. The performance of the RSM model is remarkable. Even if none of the models is able to give the exact experimental pattern on the map of turbulence, the RSM model seems able to predict such configuration.

scholarly journals Experimental and numerical investigation of plasma parameters in the magnetosheath

2018 ◽  
Vol 145 ◽  
pp. 03003
Author(s):  
Polya Dobreva ◽  
Monio Kartalev ◽  
Olga Nitcheva ◽  
Natalia Borodkova ◽  
Georgy Zastenker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Numerical Investigation ◽  
Euler Equations ◽  
Ideal Gas ◽  
Bow Shock ◽  
Plasma Parameters ◽  
Wind Spacecraft ◽  
The Magnetic Field ◽  
Good Agreement

We investigate the behaviour of the plasma parameters in the magnetosheath in a case when Interball-1 satellite stayed in the magnetosheath, crossing the tail magnetopause. In our analysis we apply the numerical magnetosheath-magnetosphere model as a theoretical tool. The bow shock and the magnetopause are self-consistently determined in the process of the solution. The flow in the magnetosheath is governed by the Euler equations of compressible ideal gas. The magnetic field in the magnetosphere is calculated by a variant of the Tsyganenko model, modified to account for an asymmetric magnetopause. Also, the magnetopause currents in Tsyganenko model are replaced by numericaly calulated ones. Measurements from WIND spacecraft are used as a solar wind monitor. The results demonstrate a good agreement between the model-calculated and measured values of the parameters under investigation.

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