Effects of drift angle on model ship flow
Effects of drift angle on model ship flow
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DOI：
10.1007/s00348-001-0397-0
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发表时间：
2002-05
影响因子：
2.4
通讯作者：
J. Longo;Frederick Stern
中科院分区：
文献类型：
--
作者：
J. Longo;Frederick Stern
通过对60系列CB=0.6货/箱船模的拖曳水池试验，研究了偏转角对船模流场的影响。获得了在一定范围的偏转角β和弗劳德数（Fr）以及模型自由状态下的阻力、侧向力、偏力矩、下沉、纵倾和横倾数据。对于模型固定条件（即，以零下沉、配平和横倾固定），获得了高Fr和低Fr =0.316和0.16，β=5°和10°（自由表面）以及β=10°（平均速度和压力）的详细自由表面和平均速度和压力流图。通过比较高Fr和低Fr下的结果以及β=0°时的先前数据，可以识别重要的自由表面和漂移效应。几何形状、条件、数据和不确定性分析都有足够详细的记录，以便作为计算流体动力学（CFD）验证的基准。阻力随β线性增加，斜率相同，而侧向力、漂移力矩、下沉、纵倾和横倾随β呈二次增加。波浪剖面仅在船首附近受到影响，即船首波振幅在迎风侧/背风侧增加/减小，而波浪高度在整个波场中受到影响。然而，两侧上的波包络角几乎与β=0°相同，即，近场波图案随船体旋转并且保持在与β=0°类似的波包络内。波浪振幅在迎风面/背风面显著增大/减小。尾迹区也是不对称的，背风侧楔角较大。边界层和尾流主要由船体涡系控制，该涡系由前体龙骨、舱底和破波涡以及后体舱底和反向旋转涡组成。破波涡的发生打破船首波以前没有文献记载。最大涡度，环流，最小轴向速度和轨迹的趋势进行了讨论，为每个涡。
The effects of drift angle on model ship flow are investigated through towing tank tests for the Series 60 CB=0.6 cargo/container model ship. Resistance, side force, drift moment, sinkage, trim, and heel data are procured for a range of drift anglesβand Froude numbers (Fr) and the model free condition. Detailed free-surface and mean velocity and pressure flow maps are procured for high and lowFr=0.316 and 0.16 andβ=5° and 10° (free surface) andβ=10° (mean velocity and pressure) for the model fixed condition (i.e. fixed with zero sinkage, trim, and heel). Comparison of results at high and lowFrand previous data forβ=0° enables identification of important free-surface and drift effects. Geometry, conditions, data, and uncertainty analysis are documented in sufficient detail so as to be useful as a benchmark for computational fluid dynamics (CFD) validation. The resistance increases linearly withβwith same slope for allFr, whereas the increases in the side force, drift moment, sinkage, trim, and heel withβare quadratic. The wave profile is only affected near the bow, i.e. the bow wave amplitude increases/decreases on the windward/leeward sides, whereas the wave elevations are affected throughout the entire wave field. However, the wave envelope angle on both sides is nearly the same asβ=0°, i.e. the near-field wave pattern rotates with the hull and remains within a similar wave envelope asβ=0°. The wave amplitudes are significantly increased/decreased on the windward/leeward sides. The wake region is also asymmetric with larger wedge angle on the leeward side. The boundary layer and wake are dominated by the hull vortex system consisting of fore body keel, bilge, and wave-breaking vortices and after body bilge and counter-rotating vortices. The occurrence of a wave-breaking vortex for breaking bow waves has not been previously documented in the literature. The trends for the maximum vorticity, circulation, minimum axial velocity, and trajectories are discussed for each vortex.