A specially designed circular towing tan~ was developed at the Northeast Fisheries Center (NEFC) for calibrating plankton-net flowmeters . ashore in order to provide more accurate volume estimates and to save valuable shipboard time. Results of a cross-calibration experiment with a flume in use at the Massachusetts Institute of Technology (MIT) demonstrated that calibration factors produced by ...

Microbial biofilm layer could grow on bed surfaces and affect the normal sediment properties following polluting of water resources. However, limited research is done to measure the effects of biofilm in the long run. The objective of this study was to investigate the erosion-deposition phenomena considering factors such as sediment concentration, flow velocity and bed surface along the flum...

V porovnaní so sekvenčnými výpočtami sú výpočty využívajúce paralelizmus výrazne zložitejšie. Z teoretického pohl’adu je vel’mi prirodzeným modelom paralelných výpočtov model PRAM, ktorý je analógiou modelu RAM často používaného v teórii zložitosti. Z praktického pohl’adu je však zaručenie úplnej synchronizácie a uniformného prístupu k zdiel’anej pamäti, garantovaných modelom PRAM, značne probl...

Drainage ditches are a key conduit of nitrogen (N) from agricultural fields to surface water. The effect of ditch dredging, a common practice to improve drainage, on the fate of N in ditch effluent is not well understood. This study evaluated the effect of dredging on N transport in drainage ditches of the Delmarva Peninsula. Sediments from two ditches draining a single field were collected (0-...

The present study describes entrainment characteristics of bed material into debris flow, based on flume tests, numerical and dimensional analyses. Flume tests are conducted to investigate influences of bed sediment size on erosion rate by supplying debris flows having unsaturated sediment concentration over erodible beds. Experimental results show that the erosion rate decreases monotonically ...

Hydraulic conditions required to initiate movement of unanchored residue materials are identified in the present study. Selected amounts of corn, cotton, pine needles, sorghum, soybean, sunflower, and wheat residue are placed in a flume on a sand surface, and flow is then introduced at the top of the flume in progressive increments. The discharge rate and flow velocity necessary to cause residu...

A detailed laboratory study was conducted to examine the effects of particle size on hysteretic sediment transport under time-varying rainfall. A rainfall pattern composed of seven sequential stepwise varying rainfall intensities (30, 37.5, 45, 60, 45, 37.5, and 30 mm h), each of 20 min duration, was applied to a 5 m 3 2 m soil erosion flume. The soil in the flume was initially dried, ploughed ...

The objective of this study was to investigate experimentally solitary waves run-up on sloping beaches. Conducted in the Super wave flume(5m×5.2m×300m) and the Large wave flume(2m×2m×200m)at Tainan Hydraulics Laboratory (THL), solitary waves were generated by moving the wave board forward in the manner of ramp-trajectory and solitary-wave-trajectory separately to simulate the various of wave he...

We describe a flume study of the spatio-temporal evolution of particulate gravity currents. Time series of the vertical structure of flow in terms of the forward component of velocity, flow concentration and grain-size of suspended sediment were co-measured at a different position along the flume for each of a series of nominally identical flows. The data are combined to show the spatial evolut...