Numerical Study of the Effects of an Obstacle and its Position in a Curved Channel in a Lock-Exchange Flow

Abstract

\n Researchers have recently shown interest in complex flow patterns, especially the effects of secondary flows, in a curved channel. This paper studied the obstacle effects in a gravity current in a channel with a symmetrical 120° bend using the OpenFoam toolbox and the Realizable k–ε turbulence model for simulation. The models studied included no-obstacle curved channel, curved channel with obstacle in 30° position, curved channel with obstacle in 60° position and curved channel with obstacle in 60° position with increased radius. Results showed that the obstacle directed the concentration towards the banks with its maximum value tending from the outer to the inner bank, especially in the tail. Although the post-obstacle head height did not change, that of the tail did (fell); the tail longitudinal velocity was maximized near the channel bed in areas far from the obstacle, and in the outer bank in areas near it. The secondary flow was so reduced that its lowest and most different pattern was observed around the obstacle. In displacing the latter, if the front was at a certain distance from it, the secondary flow did not change much, but if it was at the channel end, the post-obstacle secondary flow increased as the obstacle neared the lock.