spur dike is an important element for protection of river banks. spur dike causes variations in flow field, sediment transport and bed topography. the mechanism of flow and sediment transport in a channel bend is very complex, especially when a spur dike is constructed in a bend. in this paper the time variations of dimension of the scour hole and the bed’s topography were considered around a t...

abstract for investigating the effect of bed form in alluvial channels on the amount of bed load transport, a set of experiments was carried out in a tilting flume under unsteady flow conditions (hydrograph). the produced hydrographs were in triangular form with a maximum discharge of 30 to 45 lit/s/m. three size of sediment particles were used with equal to 1.5, 2.1 and 3.0mm, clear water with...

Prediction of the scour around a group of pile in the field exposed to oscillatory waves is very important for many offshore structure and coastal engineering projects. Conventional predictive formulas for the geometric properties of scour hole, however, are not able to provide sufficiently accurate results. In this paper the ANNs approach is used to predict the scour depth around pile group us...

Aerators are applied to provide air entrainment and cavitation erosion protections for high-speed flows. By traditional chute aerators in high-head bottom tunnels, it is difficult maintain effective aeration protection low-Froude-number small-slope conditions. The present study explores a wedge aerator design at the outlet, detailed experimental data on cavity entrained diffusion were obtained ...

6. Thrust power (= drag power) calculated using Lighthill's small amplitude bulk momentum model was two to three times the theoretical minimum of a flat plate of equivalent length and area moving parallel to the flow with a presumed turbulent boundary layer. 7. Froude efficiency increased with swimming speed, and it is shown that this is the usual relationship for fish studied so far. Froude ef...

The characteristics of submerged flow below vertical gate with sill upstream of horizontal diverging channel reach are analyzed based on experimental investigation. The experimental program is conducted in a laboratory flume with 10 cm wide, 31 cm deep and 3.0 m long. A diverging channel reach with fixed length and constant divergence angle is used. Polygonal sills with constant height, constan...

Roll waves are known to occur in the frictional flow of a thin layer of water down an inclined solid surface. For a layer of constant depth, the formation of these waves on a solid plane with small slope angle have been explained as a hydrodynamic instability occurring above a critical Froude number by analyzing the temporal stability of the constant velocity flow. Here we analyze the linear, s...