ROTATING CIRCULAR FLUME

Straight flumes, commonly used for experimental research on noncohe-sive sediments such as sand and gravel are not suitable for cohesive sediments (silt and clay), as the latter are usually transported in a flocculated form consisting of agglomerations of particles held together as a result of electrochemical surface forces and other bonding mechanisms. The floes are usually fragile and are susceptible to breakage by the impellers of recirculating pumps that are normally used in straight flumes. Furthermore, the transport processes of cohesive sediments are time-dependent processes with time scales ranging from hours to days; investigations of such large time-scale processes using straight flumes is not practical, as they would require excessively long flumes. An alternate approach is to use circular flumes and to generate the flow by moving the flow boundaries rather than the fluid. In the present technical note, rotating circular flume installed at the National Water Research Institute, Burlington, Ontario, Canada is described. A set of performance tests that dealt with the hydraulic characteristics of flows generated by two different modes of operation of the flume is also described. © ASCE.