HR: 0800h
AN: OS21B-1217    [Abstracts]
TI: Modelling the Turbulent Processes Around a 3-D Cylinder
AU: * Smith, H D
EM: smith.2975@osu.edu
AF: Ohio State University, Department of Civil and Environmental Engineering and Geodetic Science, 470 Hitchcock Hall, 2070 Neil Ave, Columbus, OH 43210 United States
AU: Foster, D L
EM: foster.316@osu.edu
AF: Ohio State University, Department of Civil and Environmental Engineering and Geodetic Science, 470 Hitchcock Hall, 2070 Neil Ave, Columbus, OH 43210 United States
AB: Predicting the local scour around three-dimensional cylindrical objects is dependent on the resolution of the instantaneous stresses as well as the characterization of the turbulent processes, including vortex generation and shedding. Following the work of Testik \emph{et al}.~(2004), the three-dimensional patterns of vortex generation and shedding in the steady current and wave environment will be simulated with the CFD model FLOW-3D. The quantities of vortex height, wake dimension, vortex angle, vortex rotation, and shedding frequency will be considered and compared with the laboratory data. Two turbulence closure schemes will be considered, the turbulent transport two-equation k-$\epsilon$ model and the non-transport Large Eddy Simulation (LES) model. Previous investigations in two-dimensions have shown the LES model to predict higher vortex strengths and lengths, while the k-$\epsilon$ model is found to be grid sensitive and of smaller magnitude (Smith and Foster, 2004). Shedding frequencies were comparable between the two models, with better predictions found with the LES model. \noindent {\large \bfseries References} \noindent Smith, H.~D.~and Foster, D.~L.~(2004). Modelling of flow around a cylinder over a scoured bed. \emph{J. Waterway., Port, Coastal, Ocean Eng., ASCE}. Accepted. \noindent Testik, F.~Y., Voropayev, S.~I., and Fernando, H.~J.~S.~(2004). Three-dimensional flow under structure around short horizontal bottom cylinder under steady and oscillatory flows. \emph{Phys. Fluids}. Submit.
DE: 4500 OCEANOGRAPHY: PHYSICAL
DE: 4558 Sediment transport
DE: 4568 Turbulence, diffusion, and mixing processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting