S272 : Investigation Laboratorial Influence Corrugated Sinusoidal Roughnesses On Spesifications Hydraulic Jump In Positive Slope
Thesis > Central Library of Shahrood University > Agricultural Engineering > MSc > 2015
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Abstarct: Stilling basin is a construction for energy wasting of the flow at downstream of overflows, rapids and terminals. Usually they have horizontal floor but sometimes it is inclined for more economy in floor excavation costs. Hydraulic jumps are used in stilling basins for energy wasting. Hydraulic jump is a phenomenon in hydraulic science with quick variant flow which is discussed mostly considered in any flows with free level like rivers and overflows and valves. Hydraulic jump occurs when there is a channel with free level at upstream and also ultra-critical flow at its downstream and a subcritical flow in a distance between both flows. It is a sudden change with short distance which may cause further disorders at water flow and also lots of energy dissipation. The real goal of this research is to find out any properties of hydraulic jump at the beds with semi-circle roughs in positive slope. All tests were made on a flume with a length of 5m, width 0.09 m, height 0.34m in three slopes of 0, 1 and 2 percent and Froud numerical scope of 2.6-5.2 and wave slope of ( s/t ) in limitation of 0 to 0.75 and rough height of (0.85cm, 1cm and 1.5cm) and inter-rough distance (s) of 0, 0.5, 1, 1.5 and 2cm. According to the results, in case of applying a sinus wave bed in stilling basin, it is possible to reduce secondary depth rate to primary one for about %50 at highest rate and about 5.22 of Froud number and also a reduction in the length of hydraulic jump up to %72 against classic jump in this type of basins. There is higher rates of energy wastes and reduction of estimated depth of jumps in rough basins than smooth ones. Like zero slope, we had a reduction in jump length and double depth in positive slope than smooth one with an increase in energy dissipation. The mentioned increase was higher in lower debis. Any increase in relevant distance of roughs in comparison with increasing the height of which had an acceptable effect on reducing the jump length, rolling length and double depth and also increasing of energy dissipation. Such a reduction process in lower slopes was more obvious than higher slopes.
Keywords:
#Height of roughs #Distance of roughs #Hydraulic jump #Positive slope Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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