Laser Doppler measurements in a rotating annular flume

This paper describes flow measurements in a rotating annular flume, that is an annular flume with a rotating top lid as well as a rotating bottom. Annular flumes are used for studying erosion and/or deposition of cohesive sediments in the laboratory, because these flumes have advantages over straight recirculating flumes in that effects of inflow and outflow conditions are avoided and that there are no pumps to break down suspended flocculated sediment. A disadvantage of annular flumes is that secondary flow velocity components in vertical and radial direction are generated, yielding a complex 3-D flow field that is not well known up to now.