Modeling and numerical analysis of the Earth-ionosphere waveguide using finite difference method

2005 ◽  
Author(s):  
S. Roostsaei ◽  
S. Sadat ◽  
C. Ghobadi ◽  
J. Nourinia
Keyword(s):  
Numerical Analysis ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
The Earth

The Effect of Faults on the Behaviour of the Earth Dam – Case Study of the Ourkiss Dam

2021 ◽  
Author(s):  
Hassiba Beghzim ◽  
Toufik Karech ◽  
Tayeb Bouzid
Keyword(s):  
Shear Stress ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Water Level ◽  
Difference Method ◽  
Earth Dam ◽  
The Earth ◽  
Base Displacement ◽  
Vertical Base

Abstract The analysis of the failure due to the effect of the propagation of normal and reversed faults with different angles of inclination and by sliding through the Ourkiss dam isstudied numerically. Mainly at the end of construction and at the highest water level, for this purpose the non-linear finite difference method is used considering four fault angles of inclination, activated at the center of the base of the embankment.The results of the study show that the shear stress values increase with the increase of the vertical base displacement imposed in both conditions of the dam state, and this for both normal and overturned faults.

A Co-Simulation Scalar-Potential Finite Difference Method for the Numerical Analysis of Human Exposure to Magneto-Quasi-Static Fields

2017 ◽  
Vol 53 (6) ◽  
pp. 1-4 ◽  
Author(s):  
Martin Zang ◽  
Carsten Cimala ◽  
Markus Clemens ◽  
Jennifer Dutine ◽  
Thomas Timm ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Human Exposure ◽  
Scalar Potential

Finite Difference Numerical Analysis and Experimental Measurements for Beam Profiles of Ultrasonic Creeping Wave Probe

2011 ◽  
Vol 52-54 ◽  
pp. 1074-1079
Author(s):  
Chao Lu ◽  
Ming Fang Zheng
Keyword(s):  
Numerical Analysis ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Mechanical Energy ◽  
Ultrasonic Transducer ◽  
Coarse Grained ◽  
Main Beam ◽  
Angle Of Incidence ◽  
Creeping Wave

Compare with the Rayleigh wave method, ultrasonic creeping waves critically technique for surface and subsurface defects nondestructive measurement for has the prominent advantage, which not sensitive to surface roughness in coarse-grained materials such as austenitic steel, In this paper, the propagation characteristics and beam profiles of the creeping probe were investigated using finite difference method and measured experimentally. The finite difference numerical model for reflection arc part of the IIW block was established. Through the numerical analysis, wavefront snapshots of the creeping wave propagated in the IIW block are very clear to illustrate the mechanism, and the directivity characteristic of the main beam is obtained. The creeping wave sound characteristics were observed using the dynamical photoelastic experimental method. The beam profiles of the creeping wave probe was measured on the IIW block, the experimental measurement results and the numerical analysis are in good agreement. The results are really significant to design an efficient producer for the surface and sub-surface defects detection based on the ultrasonic creeping wave method.In this paper, a numerical modeling of contact conical transducers is discussed in conjunction with wave propagation analyses by a finite difference method (FDM). Although transducers are the devices to convert electrical energy into mechanical energy and vice versa, attention in this paper is paid mostly to the study of characteristics and parameters of cones and wedges influencing their performance. Cones and wedges inserted between an ultrasonic transducer and the specimen provide the transducer with enhanced capability for point or line contact with the specimen. We study the effect of the dimensions, shape and aperture on the frequency response and the angle of incidence of the wave. Through the testing transducer modeling, some conclusions have been drawn from the analysis, which is useful to as the guideline and criteria for an optimum conical wedge design.

Numerical Analysis of Stabilization of Slopes Overlying Bedrock Using Piles and Effect of Socketed Length of Pile on Stability

2014 ◽  
Vol 580-583 ◽  
pp. 424-431 ◽  
Author(s):  
Mudthir Bakri ◽  
Yuan You Xia ◽  
Hua Bing Wang
Keyword(s):  
Numerical Analysis ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Shear Force ◽  
Factor Of Safety ◽  
Bending Moment ◽  
Computer Code

Piles are used widely for stabilization of landslides. To stabilize a slope settled on bedrock with piles the required factor of safety must be checked, and pile should be designed properly. Piles should be socketed into firm rock to prevent uprooting or overturning .In this research it is aimed to look into the socketed length of pile in bedrock. Therefore the parameters that affect the factor of safety of slope/pile system such as location, length, spacing and diameter of piles are analyzed. The effect of socketed length of pile in rock on pile behavior is investigated by plotting the shear force and bending moment diagrams along pile. The optimal pile position is found to be located slightly upper of the middle of the slope. The minimum socketed length after which the factor of safety will be remained constant is found to be 0.12L where L is pile length.FLAC3D computer code based on finite difference method is used to simulate the slope/pile system.

scholarly journals On accurate geoid modeling: derivation of dirichlet problems that govern geoidal undulations and geoid modeling by means of the finite difference method and a hybrid method

2014 ◽  
Vol 20 (2) ◽  
pp. 334-353
Author(s):  
Eduardo Del Rio
Keyword(s):  
Dirichlet Problem ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Hybrid Method ◽  
Difference Method ◽  
Gravity Data ◽  
Dirichlet Problems ◽  
Geoid Model ◽  
The Earth ◽  
Stokes's Integral

The geoid is the reference surface used to measure heights (orthometric). These are used to study any mass variability in the Earth system. As the Earth is represented by an oblate spheroid (Ellipsoid), the geoid is determined by geoidal undulations (N) which are the separation between these surfaces. N is determined from gravity data by Stokes's Integral. However, this approach takes a Spherical rather than an Ellipsoidal Earth. Here it is derived a Partial Differential Equation (PDE) that governs N over the Earth by means of a Dirichlet problem and show a method to solve it which precludes the need for a Spherical Earth. Moreover, Stokes's Integral solves a boundary value problem defined over the whole Earth. It was found that the Dirichlet problem derived here is defined only over the region where a geoid model is to be computed, which is advantageous for local geoid modeling. Moreover, the method eliminates several of the sources of uncertainty in Stokes's Integral. However, estimates indicate that the errors due to discretization are very large in this new method which calls for its modification. So, here it is also proposed an optimal combination of techniques by means of a Hybrid method and shown that it alleviates the uncertainty in Finite Difference Method. Moreover, a rigorous error analysis indicates that the Hybrid method proposed here may well outperform Stokes's Integral.

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