Abstract
Warping of foil disk turning over a flat solid surface was studied in connection with a magnetic flexible memory devices. Experiments were carried out to measure the rotating speed of moire-topography pattern due to the warping and to measure, by means of a hot-wire anemometer, the blow-off velocity of radial air flow from edge of the disk under various conditions. It was fund that the warping was caused by the secondary air flow between the foil disk and the solid surface
