円筒型人工魚礁の局所洗堀に関する研究

抄録

Local scour plays an important role on sinking phenomena of artificial fish reefs placed on sand bed in shallow seas. If artificial fish reefs sink into sea bottom, they lose their ability to gather fishes. In order to clarify this sinking mechanism and to overcome this problem, an experimental study on local scour around an artificial fish reef was initiated. This paper presents the results of experiments on scour around cylindrical artificial fish reef models in one way currents in an open channel. The local scour around artificial fish reefs is substantially different from that of bridge pier which have been investigated by many researchers because the artificial fish reef inclines and slides into the scour hole developed in scouring process. In addition to actual scour tests, a flow visualization study was carried out to understand the flow pattems around cylindrical shape models. The important parameter for estimation of the equilibrium local scour depths around the artificial fish reefs was found to be the ratio of the sediment number (Ns) to the critical sediment number (N*sc ), when the model width to water depth ratio was constant.