280
CHAPTER 6. SEDIMENT TRANSPORT MODELS
of a marina development. In this study both the waves and current scale
factors were modified to achieve calibration. Model currents were increased
over Froude-scale values, and wave heights were reduced by a factor of
2. Because currents were felt to be more important to the morphological
development, the current scale was less distorted than the wave height scale.
The morphological time scale was determined by modeling almost 100 years
of measured bed evolution.
Finally, Jianwei (1988) reported on movable-bed model investigations
of Shantou Harbor in China. The sandbar traversing the navigation channel outside of the harbor was being rapidly filled in by longshore moving
sediment. The prototype was designed according to similitude criteria (presented in the paper) intended for bedload transport under combined short
waves and currents. The model horizontal scale was Nx = 500, and the
vertical scale was Nz = 80. Preliminary tests resulted in the selection of
sawdust with d50 = 0.4 mm as the model sediment. Although the model
grain size was larger than prototype, both the model and the prototype
sediment had nearly the same fall speed. The silting morphological scale
was determined to be Ntm = 1168 based on comparison of model and prototype channel infilling rates. Various regulation schemes were then tested
to evaluate their usefulness.
CHAPTER 6. SEDIMENT TRANSPORT MODELS
of a marina development. In this study both the waves and current scale
factors were modified to achieve calibration. Model currents were increased
over Froude-scale values, and wave heights were reduced by a factor of
2. Because currents were felt to be more important to the morphological
development, the current scale was less distorted than the wave height scale.
The morphological time scale was determined by modeling almost 100 years
of measured bed evolution.
Finally, Jianwei (1988) reported on movable-bed model investigations
of Shantou Harbor in China. The sandbar traversing the navigation channel outside of the harbor was being rapidly filled in by longshore moving
sediment. The prototype was designed according to similitude criteria (presented in the paper) intended for bedload transport under combined short
waves and currents. The model horizontal scale was Nx = 500, and the
vertical scale was Nz = 80. Preliminary tests resulted in the selection of
sawdust with d50 = 0.4 mm as the model sediment. Although the model
grain size was larger than prototype, both the model and the prototype
sediment had nearly the same fall speed. The silting morphological scale
was determined to be Ntm = 1168 based on comparison of model and prototype channel infilling rates. Various regulation schemes were then tested
to evaluate their usefulness.