海上目标漂浮物水槽试验风致和流致缩比方案设计研究

Study on Scale Model Design for Wind- and Flow-Induced Drift of Maritime Targets in Tank Experiments

  • 摘要: 准确预测海上漂浮物(如渔船、救生筏)在复杂海况下的漂移行为对海上搜救行动有重要参考价值。本研究基于量纲分析原理,推导了适用于风-浪-流实验室水槽的缩比模型相似准则,该准则综合考虑了实验室水槽的物理尺寸与量程限制、南海海域渔船和救生筏的典型尺度以及强风急流环境模拟需求,据此确定了试验中关键物理量(几何尺度、风速、流速等)的缩尺比。基于此准则,设计并制作了代表性的缩比模型,包括半载与满载救生筏、假人及渔船。在可控的水槽环境中,开展了模型试验,观测了这些漂浮物在纯风致驱动、纯流致驱动及风-流耦合驱动下的漂移行为特性。试验结果表明:①风致漂移中,漂移速度与风速呈显著线性关系,其中半载救生筏的拟合方程为 y=0.032 8x+ 0.050 8 ,满载救生筏的拟合方程为 y=0.025 4x-0.018 9 ,与等效外海实测数据吻合良好;②纯流致漂移中,流漂系数近似为1;③在风-流耦合驱动下,满载救生筏漂移速度的理论计算值与试验实测值的平均误差为4.8%,且变化趋势一致;同时,基于模型试验结果反演得到的拖曳系数与外海等效计算结果误差不超过5%。综上,本研究建立的缩比模型试验方案成功再现了漂浮物的主要漂移机制,风致、流致漂移结果与外海观测相符,风-流耦合驱动漂移结果与理论预测一致,验证了所推导相似准则及采用的缩尺比的合理性与可靠性,为利用物理模型试验研究海上漂浮物漂移问题提供了有效方法。

     

    Abstract: Accurately predicting the drift behavior of floating objects (such as fishing boats and life rafts) under complex sea conditions is of great reference value for maritime search and rescue operations. Based on the principle of dimensional analysis, this study derived a similarity criterion for scaled model tests in a laboratory wind-wave-current flume. The criterion comprehensively considers the physical dimensions and measurement limitations of the flume, the typical scales of fishing boats and life rafts in the South China Sea, and the requirements for simulating strong winds and rapid currents. Accordingly, the scale ratios of key physical parameters (such as geometric dimensions, wind speed, and current velocity) for the tests were determined. Based on this criterion, representative scaled models were designed and fabricated, including half-loaded and fully-loaded life rafts, dummies, and a fishing boat. Controlled experiments were conducted in the flume to observe the drift characteristics of these floating objects under wind-induced, current-induced, and wind-current-coupled driving conditions. The experimental results show that: ①In wind-induced drift, the drift velocity exhibits a significant linear relationship with the wind speed. The fitting equation for the half-loaded life raft is y=0.0328x+0.0508, and for the fully-loaded life raft, it is y=0.0254x0.0189, both of which agree well with equivalent open-sea measurement data; ②In purely current-induced drift, the current drift coefficient is approximately 1; ③Under wind-current-coupled conditions, the average error between the theoretically calculated drift velocity and the experimentally measured value for the fully-loaded life raft is 4.8%, with consistent trends. Meanwhile, the drag coefficient derived from the model test results shows an error of no more than 5% compared to equivalent open-sea calculations. In summary, the scaled model test scheme established in this study successfully reproduces the main drift mechanisms of floating objects. The results for wind-induced and current-induced drift are consistent with open-sea observations, and the wind-current-coupled drift results align with theoretical predictions, validating the rationality and reliability of the derived similarity criterion and adopted scale ratios. This provides an effective method for studying the drift of maritime floating objects through physical model tests.

     

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