Author(s): Gudrun Hillebrand; Nils Reidar B. Olsen
Linked Author(s): Gudrun Hillebrand, Nils Reidar B. Olsen
Keywords: No Keywords
Abstract: Annular flumes are a commonly used type of test rig for laboratory studies on cohesive sediment transport as the flow is generated in a way designed not to interfere with flocculation. A major characteristic of the annular flow are distinct secondary currents, i. e. the flow field is clearly three-dimensional. The hydraulics of two open annular flumes with a free water surface at the University of Karlsruhe, Germany, are analyzed by means of measurements and numerical simulation. Flow velocities have been measured three-dimensionally by Acoustic Doppler Velocimetry in two open annular flumes of different sizes. The numerical simulations are realized in SSIIM, a model which solves the Navier-Stokes-Equations in a three-dimensional non-orthogonal grid using the k-εturbulence model. The numerical model is calibrated using experimental data of one setup of boundary conditions for each flume. Further data sets of differing configurations provide the opportunity for model validation. Furthermore, the sensitivity of the model to changes in wall roughness and initial conditions is analyzed. In order to evaluate the numerical model, experimental data on flow velocities by magnitude and flow direction as well as the turbulent kinetic energy distribution are compared with the results of the simulation. Good agreement is found for both the time-averaged flow field and the turbulence characteristics. This is a crucial prerequisite for the intended further application of the model in simulating cohesive sediment transport.
Year: 2010