Journal of Hydraulic Engineering

A study of one-dimensional tsunami propagation up river channels is presented. Laboratory experiments were conducted to examine the wave propagation characteristics and provide data for validating a numerical model. The validated numerical model, employing a Boussinesq-type equation was applied to the Tokachi-oki Earthquake tsunami which occurred on September 2003 in Hokkaido, Japan. The computational results of arrival time and water level at each wave gauge agree well with the observed data.

Effects of bubble size, bubble diffusing area, and other parameters in air diffusers on destratification are studied using laboratory- and pilot-scale tanks with two layers. Dimensionless group involving such variable as bubble size, bubble diffusing area, and tank area are used to quantify these effects. Based on the results of experiments, a model is developed to predict destratification efficiency. Bubble diameter and overall tank area are found inversely related to destratification efficiency while bubble diffusing area is directly related to destratification efficiency.

The present experimental investigation focuses on energy dissipation and turbulence production in two undeveloped and a partially developed inflow weak hydraulic jumps, measured with micro-ADVs. For the undeveloped inflow jumps, the turbulence production is mostly confined in the shear layer located in the upper part of the water column. For the partially developed inflow jump, two peak turbulence production regions are observed, one in the upper shear layer and the second in the near-wall region. Moreover, the measured energy dissipation distribution in the jumps reveals a similar longitudinal decay of energy dissipation integrated over the flow sections and of maximum turbulence production values from the intermediate jump region toward its downstream section.

This note, using a three-dimensional model of river flow and sediment transport, examines the effect of the vertical resolution and the choice a nonequilibrium adaptation length $L_s$ in predicting flow and sediment transport around groins in China’s Yongding River. The results show that a fine vertical grid and nonequilibrium sediment transport model provide good predictions, especially on the river bed profile with an obvious main channel and flood plain.

The present technical note aims to discuss a depth-averaged turbulence parameter in relation to the incipient motion of particles. The proposed stability equation emphasizing a depth-averaged turbulence parameter, is validated for the cases of bed protection in a steep channel and on a broad-crested weir. A design diagram representing load and resistance of movement has been introduced for turbulent flow conditions in which the transport of particles or the damage to the bed protection is expressed by the critical Shields parameter.

Clear-water scour due to a short vertical (pressure flow) contraction was investigated in a laboratory channel. Two approach velocities were studied for a (nominally) single configuration of depth and degree of contraction, with experiments conducted for various durations up to a maximum of 48 h, and the evolution of the scour hole over time monitored. The location of maximum scour in both cases was observed to occur downstream of the contraction, with maximum scour depths substantially in excess of values predicted by published models, even though equilibrium scour conditions were not reached.