Secondary flows over artificial bed strips.
Date of Issue2005
School of Civil and Environmental Engineering
Characteristics of open channel flows can be significantly modified in the presence of secondary flows. In this study, cellular secondary flows were artificially generated with alternate rough and smooth bed strips, which were aligned longitudinally in an open channel. Flow measurements were conducted with a two-dimensional Laser Doppler Anemometer system. Experimental results show that the distributions of the primary velocity and streamwise Reynolds shear stress that are altered in the presence of the secondary flows clearly deviate from those observed for two-dimensional open channel flows. The modified streamwise velocity can be represented by a function proposed in the log-wake form but varying periodically in the lateral direction. This study also demonstrates that the flow field can be linearized so that a flow quantity can be generally decomposed into two components, one being related to the average base flow and the other symbolizing the perturbation caused by the bed configuration. This perturbation-based approach finally provides an analytical description of the altered Reynolds shear stress distribution that differs from the linear profile used for two-dimensional open channel flows.
DRNTU::Engineering::Civil engineering::Water resources
Advances in water resources
© 2005 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Advances in Water Resources, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1016/j.advwatres.2004.12.008]