段波の発生とその発達に関する研究

Abstract

Experiments on behaviours of the unsteady flow caused by dam breaking were con-ducted in order to examine the applicability of analytical methods to dam breaking problemand to find the transitional process of hydraulic bore with variation of ratio of upstreaminitial depth to downstream one. The dam breaking was simulated by rapid pull-up of avertical gate installed in uniform rectangular channel.It was shown that there were four patterns of hydraulic bores distincted by the initialrelative depth: (a) profile given by Ritter's dam break function, (b) moving hydraulicjump, ? unstable state of undular bore and (d) stable state of undular bore.The flow profile, celerity of the bore front and the maximum height of the bore obta-med by experiments showed a fairly good agreement with the results of numerical calcula-tions. At last, stability of the undular bore was investigated.