This Elektromanyetikte Sonlu Farklar Metodu from: Their ASIN: Listed with price at, Now visitor can buy this product at $, Elektromanyetikte . Title: ZAMAN-UZAYDA SONLU FARKLAR YÖNTEMİN DEZAVANTAJLARI İÇİN Elektromanyetikte Maxwell denklemleri, kısmi diferansiyel denklemler (KDD) olup Nümerik çözümlerde, KDD’lerin ayrıklaştırılmasından dolayı, ZUSF yöntemi. Bu yöntemler sonlu farklar yaklaşımları olan; zamanda geri adımla merkezi fark, zamanda ileri adımla merkezi fark, Du Fort-Frankel yöntemi ve Crank-Nicolson.
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This study compares the frequently used finite difference methods for two dimensional 2D modeling of transient electromagnetic method TEM. Also electromagnetic boundary conditions are mentioned to define the electromagnetic model.
Finite difference methods was used for modeling of electromagnetic field diffusion in two dimensional homogeneous media. Comparisons have been done by accuracy, stability, consistency and process CPU time.
Electromagnetic theory is farkla to understand how the electromagnetic diffusion behaves in materials. Electromagnetic diffusion occurs only when electromagnetic wave frequency is very low.
Therefore, wave type behavior is negligible on low frequencies where diffusion type behavior is dominant. Hence, the derivation of electromagnetic diffusion equation explained for homogeneous media when electromagnetic source terms are excluded.
Ari, Niyazi [WorldCat Identities]
Because the electromagnetic source is shutted down when the electric field is recorded. TEM method has a wide application area and has afrklar used by many geophysicist.
Mineral and geothermal explorations and static shift problem in Magnetotelluric method elektroanyetikte a few examples of these applications. In this study, analytical expressions for a double line source generating the 2D electric field has been used as initial condition. Finite difference approximations used in this study are forward-time centered-space scheme FTSC. In other words, the linear approximation has elektromwnyetikte used, other terms are negligible and not dominant as first one.
Each scheme has been analzed in terms of stability, consistency, accuracy and relative computational speed. Crank-Nicholson and Du Fort-Frankel methods have been found to be more accurate and stable than other methods. For this reason, Du Fort-Frankel method has been found to be always out of running method.
Manyetik Modelleme FDTD-FEM
Fully explicit method has failed in terms of both accuracy and stability. Du Fort-Frankel scheme has been found to be superior than other methods when the CPU time is considered. Because this method does not require solution of the system of linear equations as in Crank-Nicolson method. To solve these large linear systems, their specific properties like symmetric or positive definiteness are helpful.
This is generally related to finite difference grid and boundary conditions of the model. In this study, linear system has been found to be symmetric and positive definite.
Hence Conjugate-Gradient method which is known as an optimization method has been used to solve this large linear system. All scripts and functions were coded by author to optimize the solution of the specific problem which is electromagnetic propagation in two-dimensional homogeneous media. The electromagnetic diffusion for two different homogeneous media has been shown as snapshots for three different values of time. Two stations has been selected for comparisons with the analytical solution.
In these comparisons, Crank-Nicolson and Du Fort-Frankel method have been found to be more accurate with less than two per cent relative error. Other methods have been found to have much more relative error relative to Crank-Nicolson and Du Fort-Frankel method.
Regular grids have been used to estimate how accuratetly values of left and right boundaries are calculated.
Both Crank-Nicolson and Du Fort-Frankel methods have been found to be superior in terms of accuracy with less than sixteen per cent relative error. Even in the worst case scenario where relative error is largest at the right and left boundaries has been found to be almost acceptable.
TE mode was predicted for electromagnetic field propagation. In the comparisons, 2D homogeneous resistivity models were used. Primary electromagnetic field for a line source was calculated using the analytical solution for a homogeneous medium.
Programs with aim of calculating transient electromagnetic field by different finite difference methods have been coded by MATLAB scripting language environment.
Comparisons of finite difference methods were made in terms of stability, consistency, accuracy and process CPU time.
MATLAB programs, used for computation of electromagnetic field of 2D homogeneous medium, has been confirmed by the analytic equation. Crank-Nicolson and Du Fort-Frankel method has been found to be most suitable methods for computing electromagnetic diffusion in two-dimensional homogeneous media.
Crank-Nicolson method has much more calculation than the Du Fort-Frankel method so this method is relatively slower.
ZAMAN-UZAYDA SONLU FARKLAR YÖNTEMİN DEZAVANTAJLARI İÇİN GEOMETRİK OPTİK YÖNTEMLERİN KULLANIMI.
Du Fort-Frankel method is farklae in some situations. Therefore, it is always good to simulate electromagnetic field propagation with hybrid methods mftodu Crank-Nicolson and Du Fort-Frankel. This type of approach guarantees stability and consistency with Crank-Nicolson method and process speed with Du Fort-Frankel method.
After gaining stability using smaller time-steps with Crank-Nicolson, Du-Fort-Frankel method can be used with larger-time-steps for computation. Since both stability and speed takes place. Furthermore, this study can be developed by using more accurate explicit methods. Adding alternate direction implicit ADI and locally one dimensional LOD methods to comparisons can provide more accurate results.