The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four ty...The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of Rpm （690, 820, and 950） were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.展开更多
In the present study, an experimental investigation of the decay of the maximum velocity and its turbulent characteristics behind a ship propeller, in ＂bollard pull＂ condition （zero speed of advance）, is reported....In the present study, an experimental investigation of the decay of the maximum velocity and its turbulent characteristics behind a ship propeller, in ＂bollard pull＂ condition （zero speed of advance）, is reported. Velocity measurements were performed in laboratory by use of a Laser Doppler Anemometry （LDA） measurement system. Earlier researchers described that the maximum axial velocity is constant at the initial stage of a ship＇s propeller jet （Fuehrer and Romisch, 1977; Blaauw and van de Kaa, 1978; Berger et al, 1981; Verhey, 1983） as reported in a pure water jet （Albertson et al., 1950; Lee et al., 2002; Dai, 2005）, but a number of researchers disagreed with the constant velocity assumption. The present study found that the maximum axial velocity decays in the zone of flow establishment and the zone of established flow with different rates. The investigation provides an insight into the decays of both the maximum velocity and the maximum turbulent fluctuation in axial, tangential and radial components and the decay of the maximum turbulent kinetic energy. Empirical equations are proposed to allow coastal engineers to estimate the jet characteristics from a ship＇s propeller.展开更多
文摘The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of Rpm （690, 820, and 950） were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.
基金supported by SPUR Studentship from Queen's University Belfastsupported by the National Natural Science Foundation of China (Grant No. 51006019)Petro China Innovation Foundation from China National Petroleum Corporation (Grant No. 2010D-5006-0208)
文摘In the present study, an experimental investigation of the decay of the maximum velocity and its turbulent characteristics behind a ship propeller, in ＂bollard pull＂ condition （zero speed of advance）, is reported. Velocity measurements were performed in laboratory by use of a Laser Doppler Anemometry （LDA） measurement system. Earlier researchers described that the maximum axial velocity is constant at the initial stage of a ship＇s propeller jet （Fuehrer and Romisch, 1977; Blaauw and van de Kaa, 1978; Berger et al, 1981; Verhey, 1983） as reported in a pure water jet （Albertson et al., 1950; Lee et al., 2002; Dai, 2005）, but a number of researchers disagreed with the constant velocity assumption. The present study found that the maximum axial velocity decays in the zone of flow establishment and the zone of established flow with different rates. The investigation provides an insight into the decays of both the maximum velocity and the maximum turbulent fluctuation in axial, tangential and radial components and the decay of the maximum turbulent kinetic energy. Empirical equations are proposed to allow coastal engineers to estimate the jet characteristics from a ship＇s propeller.
