Showing papers on "Elliptic coordinate system published in 1983"

Diffraction by a perfectly conducting elliptic cone

Abstract: In this paper, the exact solution for the electromagnetic field diffracted by a perfectly conducting elliptic cone is determined. The solution is presented in the form of a dyadic Green's function which is the most general form of solution. It is used the spheroconal coordinate system where the elliptic cone is one of the coordinate surfaces.

Gradation setting device in picture input and output system

Abstract: PURPOSE: To increase the accuracy of gradation processing and to improve the working efficiency by forming an xy coordinate system where an input picture density signal is taken as the x axis and an output picture density signal is taken as the y axis so as to form an intermediate coordinate point for several parameters and forming a gradation curve through the interplation such as quasi-Hermite interpolating method among coordinate points. CONSTITUTION: The x, y axes and y=lx are generated by a normal straight line generating means 1, the x axis is rotated counter clockwise around the origin of the xy coordinate by the 1st coordinate rotating means 2, the x axis is converted into the α axis and the y axis is converted into the β axis so as to form the αβ coordinate axes. Then each coordinate point is generated on the αβ coordinate system according to each parameter inputted by a coordinate point generating means 3. Thus, the αβ coordinate axes are rotated by the 2nd coordinate rotating means 4, the α axis is converted into the x axis and the β axis is converted into the y axis so as to form the xy coordinate system. Further, the coordinate points on the xy coordinate system are interpolated by the quasi-Hermite interpolating method by using a gradation curve generating means 5 so as to form the gradation curve. COPYRIGHT: (C)1985,JPO&Japio

Use of boundary-fitted coordinate transformation in neutron diffusion calculations for arbitrary two-dimensional geometries

Abstract: A procedure for numerically solving neutron diffusion equations in two-dimensional multiconnected regions with arbitrarily shaped boundaries is developed by using a boundary-fitted curvilinear coor...

A boundary-Fitted Coordinate Code for General Two-Dimensional Regions with Obstacles and Boundary Intrusions.

Abstract: : A code (WESC0R) for the generation of boundary-fitted coordinate systems for general two-dimensional regions with boundaries of arbitrary shape and with internal obstacles and boundary intrusions, arbitrary in shape and number, is described and instructions for input and use are given. The coordinate system is generated from the numerical solution of a system of elliptic partial differential equations with provision for controlling the spacing of the coordinate lines in the field. The transformed (computational) region is rectangular with the obstacles and intrusions transformed to slits and/or slabs. A small code to distribute points on various fundamental curves with exponential concentration is also described. This front-end code can be used to construct boundary point distributions for input to the coordinate code. A plot code for the coordinate system is also included. The boundary-fitted coordinate systems generated by this code may be used as a basis for the numerical solution of partial differential equations for any physical problem of interest. This procedure will be particularly useful where numerical models are used to analyze flow problems with complex boundary conditions. Typical examples are riverine analysis or the design and evaluation of selective withdrawal outlet works. (Author)