Effect of a nonbuoyant submerged transverse jet on bend secondary circulation

Abstract

The system of an effluent jet discharged upstream of a sharp open channel bend is investigated using large eddy simulations and particle image velocimetry. Without the jet, three distinct sub-cells of secondary circulation are distinguished by clustering instantaneous vortices: one at the inner bank, which is a characteristic of sharp bends; one in the center; and a counter-rotating outer bank cell. Upon addition of a nonbuoyant submerged transverse jet, the outer bank cell vanishes for a low momentum jet and is driven earlier in the bend for a high momentum jet, the bend’s circulation strength is redistributed from the inner bank cell to the center cell, and the development locations of the secondary circulation cells are shifted toward the inner bank. The inner bank cell develops later, and its development region is constrained to be closer to the inner bank. The center cell develops earlier in the bend, and its development region encompasses the jet vortices. The momentum of the jet influences the distribution of effluent, both by increasing mixing with higher momentum and by advection through the jet-affected secondary circulation.