To efficiently estimate the behavior of a non-steady fluid and the work acting on an object by performing the arithmetic operation of the object shape only by input of surface data and using high-speed solution and highly precise solution.

This program has the function of calculating the influence coefficient matrix on the blowout and circulation of the fluid in each boundary under a boundary condition by use of coordinate position data for setting the boundary of an analysis space and characteristic data for setting the fluid characteristic as input data; the function of approximating a vortex layer to the vicinity of each boundary from the speed field determined from the blowing quantity and circulation quantity to determine a discrete vortex element; the function of calculating the moving speed of the discrete vortex element; and the function of calculating the time change of the vorticity representing the discrete vortex element based on a vorticity transport equation. The movement of each discrete vortex element generated from the boundary and the time change of the representative vorticity are Lagrangian-followed to simulate the fluid phenomenon.