نتایج جستجو برای: spillway

تعداد نتایج: 482  

2006
Heather M. Lamson Jen-Chieh Shiao Yoshiyuki Iizuka Wann-Nian Tzeng David K. Cairns

Abstract Otolith strontium:calcium ratios were used to trace lifetime movements of American eels (Anguilla rostrata) captured in salt-water bays and adjoining freshwater ponds in Prince Edward Island, Canada. Eels were classiWed into migratory contingents based on their movement patterns. A pond with a pool-and-weir salmonid Wshway and a pond drained by a low-gradient channel contained eels tha...

Spillways are responsible for draining floods in dams. However, morning glory spillways are considered as free spillway type. In floods, a submerged flow is formed in their crest. This factor leads to severe pressure fluctuations in the shaft, suction and vibration of the structure and also reduces the spillway efficiency. Insufficient knowledge of the hydraulics of the submerged flow will be a...

Journal: :Hydrology 2021

Shock waves are generated downstream of spillways during flood operations, which have adverse effects on spillway operations. This paper presents the physical model study shock at Mohmand Dam Spillway project, Pakistan. In this study, hydraulic analysis was carried out to investigate its generation mechanism. Different experiments were performed analyze rooster tail a flat chute and examine fac...

2001
Dong ZHANG Zhiping LIU Tailai JIN

Abstract The paper concerns with the relationship between cavitation inception бi and sound pressure level (SPL). A case study of Xiaolangdi Hydro-project has been taken as a typical example, which demonstrates the standard criterion of SPL indicating cavitation inception. Cavitation inception of an orifice plate used for energy dissipation in a tunnel spillway has been witnessed and verified b...

Journal: :Science 2002
Rossman P Irwin Ted A Maxwell Alan D Howard Robert A Craddock David W Leverington

At 8 to 15 kilometers wide, Ma'adim Vallis is one of the largest valleys in the martian highlands. Although a groundwater source was previously suggested, the channel originates at a spillway in the divide of a approximately 3,000,000-square-kilometer closed drainage basin. The interior morphology of this source basin, including likely shoreline features following topographic contours, suggests...

2003
C. W. Hirt

Overview In free-surface flows the turbulence in the liquid may be sufficient to disturb the surface to the point of entraining air into the flow. This process is important, for example, in water treatment where air is needed to sustain microorganisms for water purification and in rivers and streams for sustaining a healthy fish population. Air entrainment is typically engineered into spillways...

2001
H. Chanson S. Aoki

Abstract: Flood waves resulting from dam break and spillway gate malfunction may have dramatic impacts. Two related cases are the overtopping of a dam by flood waves and a sudden water release down a stepped cascade. In each instance, some energy dissipation takes place and classical dam break theory are inappropriate. Both cases were investigated in large-size facilities and in a prototype. Ne...

2003
Hubert CHANSON

Although field observations of sudden spillway releases highlighted strong aeration of dam break wave flows, no study investigated these two-phase flow characteristics. New original experiments were conducted down a 24 m long stepped waterways. Dam break wave propagation showed an equivalent flow resistance similar to steady flow conditions (f ~ 0.05). Detailed unsteady air-water flow measureme...

Journal: :journal of water sciences research 0
h.r vosoughifar assistant professor of islamic azad university, south tehran branch, faculty of engineering and technology. a.r daneshkhah m.s. graduate of civil engineering, majoring in hydraulic structures, faculty of engineering and technology, azad university, south tehran branch

in this research, the numerical method of computational fluid dynamics and dimensionless parameter of froude number have been applied to determine the flow regime over ogee spillways.froude number is a dimensionless dynamic parameter calculated using the square root of the ratio of inertia force and gravitational force. considering that the study of the regimes of flow over hydraulic structures...

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