Accession Number : ADD018421

Title :   Apparatus and Method for Computing Unsteady Flows by Direct Solution of the Vorticity Equation.

Descriptive Note : Patent, Filed 22 Feb 96, patented 4 Feb 97,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Grant, John R

Report Date : 04 Feb 1997

Pagination or Media Count : 11

Abstract : Fluid flow characteristics are calculated directly from a two dimensional surface model of the object. A plurality of surface nudes with defined boundary conditions are established on the surface model. Consecutive layers of nodes are created a preset distance outward from salt surface model. Curved panels are defined passing through three nodes at a layer and a surface shape function is established for each panel from previous panels or from the boundary conditions. The fluid flow velocity for the next layer is developed from the velocities calculated at the previous layer and the shape function. Triangular elements arc created by connecting a node on the next layer with two nodes from the previous layer to form an element. First and second vorticity gradients can be calculated for the current node at a time segment from the parameters associated with the previous layer of interest nodes at that time increment. This can be combined with the calculated diffusion velocity for the node to produce a rate of change of vorticity with respect to time which can be used to calculate the velocity of the fluid at the node.

Descriptors :   *COMPUTATIONS, *UNSTEADY FLOW, *PATENTS, VELOCITY, TIME INTERVALS, MODELS, LAYERS, TWO DIMENSIONAL, PANELS, SHAPE, VORTICES, NODES, TIME, SURFACES, BOUNDARIES, CURVATURE, SOLUTIONS(GENERAL), FLOW RATE, DIFFUSION, EQUATIONS, RANGE(DISTANCE), FLUID FLOW, GRADIENTS

Subject Categories : Numerical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE