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Surface Integral Equation (surface + integral_equation)

Distribution by Scientific Domains

Engineering	100%

Selected Abstracts

Self-propulsion of oscillating wings in incompressible flow

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2008
A. Carabineanu
Abstract In this paper, we show that the oscillatory motion of an airfoil (wing) in an ideal fluid can determine the apparition of thrust. In the framework of the linearized perturbation theory, the pressure jump over the oscillating wing is the solution of a two-dimensional hypersingular integral equation. Using appropriate quadrature formulas, we discretize the oscillatory lifting surface integral equation in order to obtain the jump of the pressure across the surface. Integrating numerically, we obtain the drag coefficient. For some oscillatory motions, if the frequency of the oscillations surpasses a certain value, the drag coefficient becomes negative, i.e. there appears a propulsive force. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Efficient analysis of wireless communication antennas using an accurate [Z] matrix interpolation technique

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2010
Yikai Chen
Abstract An accurate impedance matrix interpolation technique based on the surface integral equation (SIE) is presented for the analysis of wireless communication antennas over wide frequency bands. The first-order derivative of the impedance matrix at the internal frequency is considered in the cubic polynomial-based interpolation scheme, thus the novel impedance matrix interpolation scheme will provide high accuracy and high efficiency over a frequency band. To demonstrate the efficiency and accuracy of the proposed method, numerical results for planar inverted F antennas (PIFA) and a wideband E-shaped patch antenna are presented. Good agreement among the interpolation results, exact MoM solutions, finite element method (FEM) solutions, and measured data is observed over the bandwidth. Besides, dimensions of the feeding probe are also studied to investigate their effect on the input impedance and radiation patterns. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source]

Extension of impedance matrix compression method with wavelet transform for 2-D conducting and dielectric scattering objects due to oblique plane-wave incidence

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2002
Jin Yu
Abstract The impedance matrix compression (IMC) technique is applied to analyze the square method,of-moments (MoM) matrix arising from the surface integral equation for 2-D conducting and dielectric objects with oblique plane-wave incidence. The induced current components are processed separately by using wavelet basis functions. The comparison between cylinders with circular and square cross section is presented to show the effectiveness of IMC, which depends on the geometry of the object and the wavelet transform matrix. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 53,56, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10371 [source]

Third and fourth Stokes parameters in polarimetric passive microwave remote sensing of rough surfaces over layered media

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008
Leung Tsang
Abstract We consider the four Stokes parameters in microwave emission from a layered medium with the top interface being a rough surface. The rough surface varies in one horizontal direction so that azimuthal asymmetry exists in the 3-D problem. Dyadic Green's functions of multilayered media are used to formulate the surface integral equations. Periodic boundary conditions are used. The numerical results show that the presence of the layered media below the rough surface reduces the vertical and horizontal brightness temperatures. The interaction between the rough surface and the layered media also enhance the third and fourth Stokes parameters. In particular, the fourth Stokes parameter can be large for such geometrical configurations. Results show that the nonzero third and fourth Stokes parameters exist for all frequencies and are particularly large when the rough surface has large slope. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3063,3069, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23892 [source]