  The complete flow field surrounding a rotating cylinder is calculated by
solving the Navier-Stokes equations using the finite difference method. The
numerical simulation is performed on a transformed rectilinear grid, with axes
representing the radial and angular dimensions. Different boundary conditions
of the simulations are tested by changing the tangential speed of the rotating
cylinder, ranging from subsonic to supersonic speed. The following variables in
the modeled flow fields are analyzed: temperature, velocity, pressure, density,
and stress. The large gradient of velocity near the cylinder is found to create
high stress, which leads to rise in temperature. Pressure and density near the
cylinder decreases as the speed of the cylinder increases. The proposed
simulation method and analysis of air flow can be extended to the modeling of
air flow around a Diabolo.

Computational Physics