Abstract In this paper a new procedure for detection and quantification of the main features of ship models bubbly wake is presented. The method is based on light scattering characteristics of laser beams passing through the wake of ship models. An optical light scattering model is developed and validated in a series of steady bubbly flow tests in a water tank, with time-invariant mean multiphase flow properties. Then a series of unsteady tests are conducted in a towing tank so as to study bubbly wake properties of a transom stern model. Temporal wake strength and its final detection time and length are measured using light scattering measurements. Light scattering analysis provides longitudinal, lateral, and vertical distributions of the wake without any flow intrusion. Also by combining the experimental and analytical results, a complementary assay for determination of average bubble size and bubble number density distribution is presented. Effects of model velocity on the bubbly wake features of the transom stern are also investigated using the suggested procedures. Results indicate that increasing the model velocity increases the total bubbly wake length and lifetime. Details of the wake lateral distribution reveal the prominent contribution of transom stern diverging waves on the bubbly wake air entrainment.

中文翻译：

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使用光学激光束散射特性对船尾模型气泡尾流的实验研究

摘要 本文提出了一种检测和量化船模气泡尾流主要特征的新方法。该方法基于通过船模尾流的激光束的光散射特性。光学光散射模型在水箱中的一系列稳定气泡流测试中得到开发和验证，具有时不变的平均多相流特性。然后在拖曳水箱中进行了一系列非定常试验，以研究艉艉模型的气泡尾流特性。使用光散射测量来测量时间尾流强度及其最终检测时间和长度。光散射分析提供尾流的纵向、横向和垂直分布，而没有任何流动侵入。同样通过结合实验和分析结果，提出了用于确定平均气泡大小和气泡数密度分布的补充分析。还使用建议的程序研究了模型速度对尾艉的气泡尾流特征的影响。结果表明，增加模型速度会增加总气泡尾流长度和寿命。尾流横向分布的细节揭示了尾尾发散波对气泡尾流空气夹带的突出贡献。