透過光を利用した水流による底質フラックスの画像計測法

抄録

A planar measurement system for sediment fluxes is developed to quantify the 2D sediment transport in laboratory flumes. The system consists of image-based techniques respectively for concentration and velocity measurements. Negative images of sediment particles in motion are taken by a high speed camera using an electro-luminescence sheet as a backlight source. Sediment concentration is estimated from its pre-calibrated relationship with light attenuation through water volume containing sediment particles. Sediment transport velocities are simultaneously measured by PIV applied to the same images. Spatial distribution of sediment fluxes can be obtained by simply multiplying the sediment concentration and velocity at respective locations. Simple tests are carried out to verify the performance of the developed system. The results suggest that the system is capable of quantifying sediment fluxes with up to 15 % erorr in the range of less than 2.5 in light attenuation factor A.