M. Nassiri et S. Babarutsi, COMPUTATION OF DYE CONCENTRATION IN SHALLOW RECIRCULATING FLOW, Journal of hydraulic engineering, 123(9), 1997, pp. 793-805
The Lagrangian second-moment method is used to compute the dye-concent
ration distribution in turbulent recirculating flow generated in a sha
llow open channel by a sudden widening of how in the transverse direct
ion. The performance of the second-moment method is compared with the
Eulerian numerical schemes of Upwind, QUICK, HLPA, and the semi-Lagran
gian Hermite scheme. The results show that the Lagrangian second-momen
t method is an accurate and a very promising scheme for the computatio
n of concentration distribution in flows dominated by advection. It mi
nimizes the generation of numerical diffusion, is free from numerical
oscillations, and is independent of the value of Courant number. Its e
fficiency in terms of computational time is high in flows where the mi
xing is confined to a small region of the solution domain and low in h
ows where the mixing is extended in the whole solution domain. In addi
tion to an accurate numerical scheme, a necessary requirement for the
accurate prediction of concentration field is a hydrodynamic model abl
e to determine correctly the velocity held and the diffusion coefficie
nt in shallow recirculating flows.