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A simulation procedure to examine the backscattering radar cross-section (RCS) of a hypersonic object with plasma sheath is presented. Computational fluid dynamics tool is adopted to resolve the distributions of electron density and atmospheric temperature, and then the complex dielectric constant of plasma sheath are found. Volume-surface integral equation method is employed to extract the backscattering...
A nonperturbative and universal FDTD model is proposed to investigate the nonlinear responses from metallic metamaterials. By coupling the hydrodynamic equation to the Maxwell equation, the multiphysics model enables to investigate both linear and nonlinear dynamics of free electron gas within the metallic metamaterials without any approximations and prior assumptions. Moreover, the proposed FDFD...
In this paper, the time domain volume surface integral equation method is used to analyze PIN diode Limiter under high voltage with a field-circuit coupling algorithm. Besides, the mathematical equations of lumped charge model are also combined here. The electromagnetic field-circuit coupled system matrix of microwave nonlinear element loaded circuit problem is established. With Newton iteration method,...
To study the transverse flow pressure and flow pressure torque generated by non-uniform flow that the ship encounters when it passes the entrance of breakwater in the process of driving away from the port, a ship model sailing at the end of breakwater and a digital basin were established by utilizing computational fluid dynamics. In this way, numerical calculation was conducted for the tide field...
There were measuring errors when the inconstant currents are measured with shunts, because the skin effect increased the resistance and decreased the inductance. This paper has analyzed the circuit model of shunts with different frequency by using field-circuit coupling method and the analysis results have been validated by experiment. This paper provided a more accurate engineering method to analyze...
This paper summarizes recent development in efficient solution of electromagnetic problems based on integral equation. First, hybridization of integral equation method with differential equation method is introduced for reverberation chamber (RC) modeling. It is shown that the hybrid method significantly reduces computational load for RC modeling. Second, dimension reduction for efficient analysis...
In this paper, the implementation of UPML in DGTD is presented. Based on equations of UPML and the characteristics of the unstructured grid, time stepping strategy is given. The numerical results of radiation and scattering are demonstrated with good absorption of UPML in DGTD.
A new method for making an explicit time-domain finite-element method unconditionally stable is developed for general electromagnetic analysis, where the dielectrics and conductors can be inhomogeneous, lossless, and lossy. In this method, for a given time step, we find the unstable modes that are the root cause of instability, and deduct them directly from the system matrix resulting from a time-domain...
The finite-difference time-domain (FDTD) method is proposed to model Maxwell-Bloch equations with a four-level quantum system for investigating the nano-structures incorporated with gain materials. To understand the lasing behavior and loss compensation mechanism of the gain material, a self-consistent computational scheme is presented. Comparisons between optical and homogeneous Pumping are given...
Metamaterials have attracted much attention in recent years because of their electromagnetic exquisite proprieties. For this we will introduce in this paper the modeling of a whole structure in metamaterials by equivalent circuit model. We begin by modeling the SRR (Split Ring Resonator), then we model the HIS (High Impedance Surfaces). In order to validate models, we compare the results obtained...
To ensure numerical stability, the Courant-Friedrichs-Lewy (CFL) condition has to be imposed in an explicit time-domain numerical method. It limits the time step and therefore computational efficiency. In this paper, we use the FDTD (finite difference time domain) method as an example and present a stable wave-equation based FDTD method with a simple solution procedure. The method is based on the...
In some applications, such as emissivity calculation of finite object, scattering field and power must be calculated accurately. However, conventional method based on equivalent source integral on closed equivalent surface might not give accurate enough results, because the numerical error of scattering field in the strong scattering side of the object might have significant effect on the scattering...
In this paper, the one-step leapfrog weakly conditionally stable finite-difference time-domain (WCS-FDTD) method for lossy media is proposed. By adopting Crank-Nicolson and Peaceman-Rachford schemes, the derived equations involve the calculation of lossy media terms at two time steps. To check the effectiveness of proposed method, numerical investigations are performed. It is shown that the proposed...
An unconditionally-stable four-stages split-step convolutional perfectly matched layer (PML) algorithm is presented for modeling open region finite-difference time-domain (FDTD) applications. In the proposed method, the Maxwell's matrix is separated into four sub-matrices. Accordingly, the time step is divided into four sub-steps. Then, the formulation of the proposed method is derived. Furthermore,...
In order to study the ship navigation deflection, the motion model of the ship is established on the basis of CFD (computational fluid dynamics), for the numerical calculation and simulation of the motion state of S60 ship model in different water depths. Meanwhile, the calculation result is compared with the experimental data for verification, and it turns out that the two matches well. Afterwards,...
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