Abstract: A method for calculating a physical flow quantity of a fluid or magnetofluid propagating over a surface such as in a wind tunnel. The method includes the steps of setting a main mesh having predetermined mesh spacing relative to space and time. The method sets a sub-mesh having a mesh spacing smaller than that of the main mesh in space regions between points in the main mesh, in which the magnitude of inclination of the physical quantity is above a first preset level. Next, the method sets mesh points, at which the magnitude of inclination of the physical quantity is greater than a second level that is greater than the first level, as singular points. Thereafter, the method calculates, via a CIP method, the values at the mesh points of the main mesh after an increment of time (a mesh spacing of the main mesh over the time variable). The values at the mesh points of the sub-mesh after the increment of time are also calculated via the CIP method.