STUDIES ON THE LOCAL SCOUR FROM FLOWS DOWNSTREAM OF AN OUTLET (1)

Abstract

In order to prevent the scour resulting from flows downstream of an outlet, it is necessaryto establish the mechanics of the scour. A series of experimental investigations on the localscour from wall jets issuing from a submerged outlet has been performed by using small andlarge experimental water tanks and sediments of eight kinds of size.As a first report, general considerations on the nature of scour, such as profiles of scourholes, variations of maximum depth of scour with time, influence of tail water depth on thescour, periodicity of scour and similitude in the phenomena of scour, are described based onthe experimental results, and moreover, a theoretical approach to disclose the mechanismof the scour for an initial step of scour is presented.In order to prevent the scour resulting from flows downstream of an outlet, it is necessaryto establish the mechanics of the scour. A series of experimental investigations on the localscour from wall jets issuing from a submerged outlet has been performed by using small andlarge experimental water tanks and sediments of eight kinds of size.As a first report, general considerations on the nature of scour, such as profiles of scourholes, variations of maximum depth of scour with time, influence of tail water depth on thescour, periodicity of scour and similitude in the phenomena of scour, are described based onthe experimental results, and moreover, a theoretical approach to disclose the mechanismof the scour for an initial step of scour is presented