2-D SIMULATION OF OVERLAND FLOW AROUND GULLY HEADCUT

Abstract

Formation and migration of gully headcut is one of the complicated phenomena, which often appears in incised channels. Flume experiments have been conducted to investigate the flow field along and around the headcut. The fixed bed experiments with oblique headcuts show that the flow is concentrated to the head (upstream part) of the gully, which has been reproduced in numerical simulations for both of fixed and movable bed conditions. Headcut migration rate depends on the unit discharge along the brink and the change in elevation of energy-grade line passing the headcut. The initial shape of the headcutis an important parameter for the formation and movement of gully headcut. A sharp shape at the head of the headcut is required for the proper development of gully.