Vortex extraction apparatus, method, program storage medium, and display system

A non-transitory computer-readable storage medium that stores a vortex extraction program executed by an arithmetic apparatus that executes a program and causing the arithmetic apparatus to operate as a vortex extraction apparatus comprising:

• a data acquisition section that acquires flow velocity data at a plurality of points distributed in a fluid space;
• a first numerical data calculation section that calculates, for each vertex of each of voxels into which the inside of the fluid space is split, first numerical data indicating whether the vertex is located inside or outside a vortex region in the fluid, based on the flow velocity data acquired by the data acquisition section;
• a text data creation section that determines a center line of the vortex in the fluid based on the flow velocity data acquired by the data acquisition section and determines the size of the vortex region around the center line based on the first numerical data on each vertex calculated by the first numerical data calculation section, the text data creation section creating text data indicative of the center line and the size;
• a polygon count reduction processing section that counts the number of polygons defining a surface of the vortex region and each including an isosurface of the first numerical data calculated by the first data calculation section and integrates the plurality of voxels with new voxels into which the fluid space is roughly split until the number of polygons is equal to or smaller than a set value, to decimate the first numerical data and thereby obtain first numerical data corresponding to each vertex of each of the new voxels;
• and
• a data output section that outputs the text data created by the text data creation section and the first numerical data obtained by the polygon count reduction processing section and corresponding to each vertex of each of the new voxels.

A vortex extraction method, comprising:

• acquiring flow velocity data at a plurality of points distributed in a fluid space;
• calculating, for each vertex of each of voxels into which the inside of the fluid space is split, first numerical data indicating whether the vertex is located inside or outside a vortex region in the fluid, based on the acquired flow velocity data;
• determining a center line of the vortex in the fluid based on the acquired flow velocity data, determining the size of the vortex region around the center line based on the calculated first numerical data on each vertex, and creating text data indicative of the center line and the size;
• counting the number of polygons defining a surface of the vortex region and each including an isosurface of the calculated first numerical data, and integrating the plurality of voxels with new voxels into which the fluid space is roughly split until the number of polygons is equal to or smaller than a set value, to decimate the first numerical data and thereby obtain first numerical data corresponding to each vertex of each of the new voxels;
• and
• outputting the created text data and the obtained first numerical data corresponding to each vertex of each of the new voxels.

A vortex extraction display system comprising:

• a vortex extraction apparatus that creates data indicative of a vortex in a fluid space based on flow velocity data on each of a plurality of points distributed in the fluid space;
• and
• a vortex display apparatus that receives the data created by the vortex extraction apparatus to display the vortex,
• wherein the vortex extraction apparatus comprises:
• a data acquisition section that acquires flow velocity data at a plurality of points distributed in a fluid space,
• a first numerical data calculation section that calculates, for each vertex of each of voxels into which the inside of the fluid space is split, first numerical data indicating whether the vertex is located inside or outside a vortex region in the fluid, based on the flow velocity data acquired by the data acquisition section,
• a text data creation section that determines a center line of the vortex in the fluid based on the flow velocity data acquired by the data acquisition section and determines the size of the vortex region around the center line based on the first numerical data on each vertex calculated by the first numerical data calculation section, the text data creation section creating text data indicative of the center line and the size,
• a polygon count reduction processing section that counts the number of polygons defining a surface of the vortex region and each including an isosurface of the first numerical data calculated by the first data calculation section and integrates the plurality of voxels with new voxels into which the fluid space is roughly split until the number of polygons is equal to or smaller than a set value, to decimate the first numerical data and thereby obtain first numerical data corresponding to each vertex of each of the new voxels, and
• a data output section that outputs the text data created by the text data creation section and the first numerical data obtained by the polygon count reduction processing section and corresponding to each vertex of each of the new voxels.