Abstract
In compound open-channel flows, it is very important to clarify the interaction between main-channel and floodplain induced by coherent vortices, so-called secondary currents, etc. In this paper, a new quantitative visualization technique called the "Particle-Tracking Velocimetry (PTV)" was used to investigate space-time correlation structures of coherent vortices because instantaneous velocity components can be obtained at all grid points of laser-light-sheet (LLS) from continuous four images of one particle (four-field-images'method). At that time, a new-type two-component fiber-optic laser Doppler anemometer (FLDA) was used to verify the accuracy of PTV measurements.
