scholarly journals Spectral Analysis of Magnetic Anomalies Due to a 2-D Horizontal Circular Cylinder: A Hartley Transforms Technique

2011 ◽  
Vol 16 ◽  
pp. 45 ◽  
Author(s):  
Mansour A. Al-Garni
Keyword(s):  
Spectral Analysis ◽  
Circular Cylinder ◽  
Real Data ◽  
Magnetic Anomalies ◽  
Horizontal Cylinder ◽  
Hartley Transform ◽  
Alternative Approach ◽  
Hartley Transforms ◽  
High Level ◽  
Horizontal Circular Cylinder

The spectral analysis of the vertical effect of magnetic anomalies due to a 2-D horizontal circular cylinder is presented using Hartley transform. Hartley transform is an alternative approach to the famous complex Fourier transform. The depth to the center of the horizontal cylinder can be computed by a simple equation as a function of frequency. A synthetic example has been used to illustrate this technique and the validity of this approach has been proved by applying it to real data of a narrow band of quartz-magnetite in Mangampalli near Karimnagar town, India. The noise analyses were tested on the technique and showed a high level of confidence. The results of the field example are in good agreement with the ones published in the literature.  

Water Wave Diffraction and Radiation by a Submerged Horizontal Circular Cylinder in Front a Vertical Wall

2020 ◽  
Author(s):  
Ai-jun Li ◽  
Yong Liu
Keyword(s):  
Circular Cylinder ◽  
Analytical Solutions ◽  
Wave Diffraction ◽  
Water Wave ◽  
Vertical Wall ◽  
Horizontal Cylinder ◽  
Linear Potential ◽  
Polar Coordinate ◽  
Horizontal Circular Cylinder ◽  
Unbounded Fluid

Abstract This article studies water wave diffraction and radiation by a submerged horizontal circular cylinder in front of a vertical wall under the assumption of linear potential flow theory. Based on the image principle, the hydrodynamic problem of a horizontal cylinder in front of a vertical wall is transformed into an equivalent problem involving symmetrical cylinders in a horizontally unbounded fluid domain. Then, analytical solutions for the present physical problem are developed using the method of multipole expansions combined with the shift of polar coordinate systems. The wave exciting forces on the cylinder as well as the added mass and radiation damping due to the cylinder oscillation are calculated. The analytical solutions converge very rapidly with the increasing truncated number of multipoles. Calculation examples are presented to examine the effects of different parameters on the hydrodynamic quantities of the cylinder. Results indicate that the hydrodynamic quantities of the cylinder in front of a vertical wall greatly differ from those in a horizontally unbounded fluid domain.

Spectral analysis of gravity and magnetic anomalies due to a vertical circular cylinder

Geophysics ◽  
1983 ◽  
Vol 48 (2) ◽  
pp. 224-228 ◽  
Author(s):  
A. Soto ◽  
S. K. Singh ◽  
C. Flores
Keyword(s):  
Spectral Analysis ◽  
Circular Cylinder ◽  
Bessel Function ◽  
Magnetic Anomalies ◽  
Gravity And Magnetic ◽  
Amplitude Spectra ◽  
Phase Spectra ◽  
Magnetic Case

Expressions for the spectra of gravity and magnetic anomalies due to a vertical right circular cylinder can be written in terms of a Bessel function and the sum of two exponentials. From the zeros of the amplitude spectra, which are the zeros of the Bessel function, an estimate of the radius of the cylinder can be obtained. The depths to the top and to the bottom enter as exponents of the exponential terms and can be evaluated by taking ratios of the spectra at several frequencies. The density or the intensity of magnetization can then be easily estimated. For the magnetic case the epicenter of the cylinder can be obtained from the slope of the phase spectra. The method has been tested on anomalies of various cylinders and was found to give good results.

Interpretation of some two‐dimensional magnetic bodies using Hilbert transforms

Geophysics ◽  
1982 ◽  
Vol 47 (3) ◽  
pp. 376-387 ◽  
Author(s):  
N. L. Mohan ◽  
N. Sundararajan ◽  
S. V. Seshagiri Rao
Keyword(s):  
Circular Cylinder ◽  
Andhra Pradesh ◽  
Theoretical Models ◽  
Magnetic Anomalies ◽  
Two Dimensional ◽  
Hilbert Transforms ◽  
Infinite Depth ◽  
The Hilbert Transform ◽  
Depth Extent ◽  
Horizontal Circular Cylinder

Procedures are formulated using the Hilbert transform for interpreting vertical magnetic anomalies of (1) the sheets (finite and infinite depth extent), (2) the dike, and (3) the horizontal circular cylinder. The applicability of the method is tested on theoretical models. The method is also applied on the well‐known Kursk field anomaly of a sheet (infinite‐depth extent) and the field anomaly of a dike of Karimnagar, Andhra Pradesh, India.

scholarly journals SIMULATION OF WAVE FORCES ON A HORIZONTAL CYLINDER

1988 ◽  
Vol 1 (21) ◽  
pp. 163
Author(s):  
Susumu Tsuzuki ◽  
Kiyoshi Horikawa ◽  
Akira Watanabe
Keyword(s):  
Circular Cylinder ◽  
Laboratory Data ◽  
Vortex Method ◽  
Wave Force ◽  
Horizontal Cylinder ◽  
Wave Forces ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Experimental Findings ◽  
Horizontal Circular Cylinder

The characteristics of wave forces acting on a horizontal circular cylinder were investigated through numerical calculations as well as experimental findings. The laboratory data on wave forces were analyzed by the concept of wave force path and classified into two types. One is the circular type and the other one is the 8 - shaped type. In order to analyze the above phenomena, the discrete vortex method was applied with appropriate assumptions. The comparison between the numerically calculated results and laboratory data shows that the simulation model proposed in this paper seems to be favorable to predict the wave forces acting on a horizontal circular cylinder within a certain range of conditions.

STANDARD CURVES FOR MAGNETIC ANOMALIES OVER LONG HORIZONTAL CYLINDERS

Geophysics ◽  
1965 ◽  
Vol 30 (5) ◽  
pp. 818-828 ◽  
Author(s):  
S. Parker Gay
Keyword(s):  
Circular Cylinder ◽  
Magnetic Anomalies ◽  
Curve Matching ◽  
Profile Curve ◽  
Complete Family ◽  
Family Of Curves ◽  
Isolated Points ◽  
Horizontal Cylinders ◽  
Magnetizing Field ◽  
Horizontal Circular Cylinder

The magnetic anomalies in Z, H, and [Formula: see text] for the long horizontal circular cylinder are shown to belong to a single mathematical family of curves for all values of strike and all values of inclination of the magnetizing field, a characteristic that was previously shown to hold for long tabular bodies, or dikes (Gay, 1963). The complete family of standard curves has been constructed and is incorporated into an interpretational scheme based on superposition with observed magnetic profiles. Comparison of cylinder anomalies with dike anomalies shows only slight differences in the two types of curves, which would be very difficult, if not impossible, to detect using interpretational methods based on a few isolated points of a profile curve, such as half‐width, distance between maximum and minimum, etc. Curve‐matching, or superposition, appears to be mandatory for reliable quantitative interpretations.

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