HR: 0800h
AN: H41A-0134    [Abstracts]
TI: Numerical Prediction For Channel Bed Changes Near Groyne In Experimental Flume
AU: * Ho, J
EM: jayho@unm.edu
AF: University of New Mexico, Civil Engineering Department University of New Mexico MSC01 1070, Albuquerque, NM 87131-0001, United States
AU: Kim, W
EM: wikim@suwon.ac.kr
AF: University of Suwon, Department of Civil Engineering University of Suwon, Suwon, 445-743, Korea, Republic of
AU: Choi, J
EM: raydedu79@yahoo.co.kr
AF: University of Suwon, Department of Civil Engineering University of Suwon, Suwon, 445-743, Korea, Republic of
AU: Ahn, W
EM: wsan@suwon.ac.kr
AF: University of Suwon, Department of Civil Engineering University of Suwon, Suwon, 445-743, Korea, Republic of
AB: Numerical modeling for groynes in a rectangular section flume was developed to predict channel bed changes and to investigate the best performing groyne installation interval. Five different porous groynes were simulated in this study to evaluate hydraulic influences on the maximum scour depth induced by the groyne. Channel surface elevation and velocity changes near groyne were measured using surface topology digital imaging system and three-dimensional acoustic doppler velocimeter. Three-dimensional solutions governed by the Reynolds averaged Navier-Stokes and continuity equations were calculated using a commercial computational fluid dynamics code, which uses the finite volume method. For considering turbulent open channel flow in this computations, k-e model and Reynolds normalization group model were employed. Permeability of the groyne was reproduced by changing the gap between 2 cm diameter of cylinders. The approach water depths and the approach velocity acquired from the physical model were treated as the boundary conditions for the numerical model. Positive velocity boundary and the continuative boundary, which consists of zero normal derivatives at the boundary for a smooth continuation of the flow through the boundary, were set for inflow and outflow of the domain (x-direction). Atmospheric pressure boundary and no-slip wall condition were assigned at the top and the bottom of the domain (y-direction), respectively. Computed maximum scour and deposition depth and channel bed changes near the groyne were compared with the physical model measurements for validation of the numerical model. Calibration statistics of a mean error and a normalized root mean squared value was provided with 95% confidence interval plot. The numerical model computations showed very positive agreement with the physical model measurements. The relationship between the maximum scour depth and groyne porosity was generated. It was found that the numerical model could complement the physical model, and this numerical model will provide valuable information for design of groyne placement interval.
DE: 1815 Erosion
DE: 1856 River channels (0483, 0744)
DE: 4255 Numerical modeling (0545, 0560)
DE: 4863 Sedimentation (1861)
SC: Hydrology [H]
MN: 2007 Fall Meeting