Measurements and large eddy simulations of the flows in some curved flumes

Abstract

The curvature of the flow in river bends and in curved flumes leads tosecondary flow normal to the main flow direction. Reynolds averagednumerical simulations, e.g. by k-ε models or RSM, fail toreproduce sufficiently the sometimes complicated secondary flow patternobserved. In the computation of the flow in a rotating annular flume both the separation of the flow from the outside wall and the turbulence energyare not reproduced correctly. For the river bend flow the reproduction of asecond counter-rotating secondary flow cell and of shear stresses of thecorrect sign, where they correspond to an observed negative eddy viscosity, proved problematic. Recently executed large eddy simulations gave better results. The computed main flow, but also the secondary flow and theturbulence energy in the rotating annular flume, hardly deviate from themeasurements. For the river bend a good reproduction of the main flow and the secondary flow is obtained, showing the second counter-rotating secondary flow cell and correct shear stresses.

This article is a modified version of the original article from the Proceedings of the 5th International Symposium on Engineering Turbulence Modelling and Measurements, Mallorca, 16-18 September 2002, which appeared in ‘Engineering Turbulence Modelling Measurements 5’, Elsevier Science, ISBN 0-08-044114-9, ed W Rodi and N Fueyo.