開水路流れに設置された橋脚周辺の水理特性について(5)

Abstract

A pier that was made up of a small circular cylinder with a larger cylinder below itwas used as the non-uniform pier model and the scouring process around it was analyzed bya mathematical simulation which was partly based on the information through experiments.The main results obtained were;1) The development of scour depth with time differs considerably based on the elevationof the lower cylinder. The differences appear remarkably when the diameter of lower (upper)cylinder becomes larger (smaller).2) When the dimension of the lower cylinder is large and its top surface is just nearthe river bed, scour is reduced than that for a uniform pier with the same diameter ofupper cylinder. But, any slight upward shift of the top surface can bring about a remarkableincrease in scour depth.