Velocity Field Measurement by Spatio-Temporal Derivative Method

Abstract

Recent developement of flow velocity field measurements using visualized flow pictures has been advanced remarkablely. Although many of these techniques have great possibility a practical universal method is not found yet. The user of the image measurement system must choose a suitable analysis method coresponding to the flow characteristics. This paper describes the spatio-temporal derivative method, which is known as a high spatial resolution technique. The several measuremed results have shown and discussed the problems and possibilities. The flow field of necklace vortex in front of full hull model, which can not be measured by the Pitot tube or the hot film, has been shown at first. The unsteady separated vortex region behind a two-dimensional aerofoil and the flow around circular cylinder in regular wave are measured.