Author(s): A. Paquier; M. O. Bristeau; S. Proust; N. Riviere; J. Y. Champagne
Linked Author(s):
Keywords: Groyne; Flow diversion; 2D model; Shallow water equations; Recirculating flow
Abstract: Hydraulic structures such as groynes or bridge piles in the main bed or buildings in the flood plain influence flows in rivers before and after overflowing. An experiment was performed in a rectangular channel in which a groyne created a recirculating zone that was limited by the downstream boundary. 3D velocity field was measured by LDA (Laser Doppler Anenometry) and water levels were determined using point gauges. Simple 2D codes solving shallow water equations were used to model this experiment; various meshes and downstream boundary conditions were applied. The comparison between the measurements and the results of the various 2D models was constituted by longitudinal profiles of water levels, of longitudinal velocities and of cross velocities as well as a map of the differences in horizontal velocity intensities. The observed differences emphasize the difficulties to simulate the processes (determined from free water surface and velocity field) from an accurate topography using any model. However, as experimental and calculated flow patterns are very similar, corrections could be applied to reach engineering purposes.
Year: 2003