An experimental study of unsteady hydrodynamics of a single scull
An experimental study of unsteady hydrodynamics of a single scull
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DOI：
10.1177/1475090211406775
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发表时间：
2011-01-01
影响因子：
1.8
通讯作者：
Cichowicz, J.
中科院分区：
文献类型：
--
作者：
Day, A. H.;Campbell, I.;Cichowicz, J.
通过现场试验和水池试验相结合的方法，研究了船体动力学对单桨水动力性能的影响。本文通过在拖曳水池和外场试验条件下对全尺寸单桨船首非定常流场进行的几组热膜测量，探讨了非定常流场中层流-湍流转捩的位置。结果表明，所测量的真实世界的粘性流行为可以成功地再现在坦克中使用的振荡子车再现在现场试验中测量的浪涌运动。可以看出，湍流和加速度之间有很强的联系;结果表明，该环节是相对不敏感的平均速度，但在加速度时程的小变化可以有显着的效果，因为可以存在的小波。层流-湍流过渡的位置的影响进行了研究，通过一系列的阻力试验，在两个不同的位置处都具有自由转捩和由湍流激励强制的转捩。结果表明，转捩位置向后移动200 mm可使阻力减少近0.5%。使用摆动副车架的非定常试验表明，非定常效应使自由转捩的总平均阻力增加约3%。
The effect of hull dynamics on the hydrodynamic performance of a single scull is investigated via a combination of field trials and tank tests. The location of laminar-turbulent transition in unsteady flow is explored via several series of hot-film measurements on the bow of a full-scale single scull in unsteady flow in both towing tank and field-trial conditions. Results demonstrate that the measured real-world viscous-flow behaviour can be successfully reproduced in the tank using an oscillating sub-carriage to reproduce the surging motion measured in the field trials. It can be seen that there is a strong link between turbulence and acceleration; results show that the link is relatively insensitive to mean velocity, but that small changes in acceleration time-histories can have a marked effect, as can the presence of small waves.The impact of the location of laminar-turbulent transition is investigated by way of a series of resistance tests, both with free transition and with transition forced by turbulence stimulation at two different locations. Results indicate that an aft movement of 200 mm of the location of transition can reduce resistance by almost 0.5 per cent. Unsteady tests using the oscillating sub-carriage indicate that unsteady effects add around 3 per cent to the total mean resistance with free transition.