FUNDAMENTAL STUDY ON INTERACTION BETWEEN DRIFTWOOD AND FREE-SURFACE FLOW IN AN OPEN CHANNEL

Abstract

 In this study, we used high speed video camera having high resolution to capture a great number of driftwood images per second for measuring driftwood velocity, and applied PIV (Particle Image Velocimetry) and PTV (Particle tracking Velocimetry) to surface flow velocity. The channel gradient, drifting length, and driftwood shape given to the relative velocity between drift-wood velocity and surface flow velocity were examined based on the motion equation of driftwood. Cylindrical driftwood be-comes faster than free surface velocity with increasing channel slope and driftwood length when the driftwood angle is small, and the product of driftwood length and channel gradient is proportional to the square of the velocity difference between driftwood velocity and surface flow velocity.