Research on the transport and dispersion of Asian carp eggs in the “man-made flood pulse” in the middle Yangtze River by Reynolds-averaged numerical simulation

Abstract

Eggs and early larvae of fishes is important to the early life stages of fish, it is closely related to the fish hatching and resource supplementation, the fish egg movement is essential to studied for re-operation ecological-flow determination, re-operation effect evaluation and fish spawning ground repair. In this paper, fish eggs of Four major Chinese carps were used as the object of study, and the fish eggs were generalized to sediment-like particles. Assuming that their diameter was constant and other mechanical properties were given, the analytic solution considering the change of lateral velocity along the curve were proposed, and the improved three- dimensional hydrodynamic model was used to simulate the distribution characteristics of the fish eggs of the sediment - like particles in the curved channel. (1) cross-section: In straight river section, cross-section of eggs distribution is more uniform in vertical direction, the middle concentration is slightly larger than the two sides in horizontal direction; in the bent river, from the convex bank to the depression concentration gradually reduced. (2) Longitudinal section: the overall concentration of eggs showed a decreasing trend along the trend, the bank near the shore, the egg concentration is increase in a certain time and region, affected by the flow field conditions. The research results can provide the basis for the egg movement simulation by the sink channel and the law of its movement.