李涵, 郝亮, 张孟杰, 等. 高弗劳德数下绕锥头回转体通气空泡流态特征及压力脉动特性实验研究[J]. 实验流体力学, doi: 10.11729/syltlx20230138.
引用本文: 李涵, 郝亮, 张孟杰, 等. 高弗劳德数下绕锥头回转体通气空泡流态特征及压力脉动特性实验研究[J]. 实验流体力学, doi: 10.11729/syltlx20230138.
LI H, HAO L, ZHANG M J, et al. Experimental study on the flow pattern and pressure fluctuation characteristics of ventilated cavitating flows around a conical axisymmetric body at high Froude number[J]. Journal of Experiments in Fluid Mechanics, doi: 10.11729/syltlx20230138.
Citation: LI H, HAO L, ZHANG M J, et al. Experimental study on the flow pattern and pressure fluctuation characteristics of ventilated cavitating flows around a conical axisymmetric body at high Froude number[J]. Journal of Experiments in Fluid Mechanics, doi: 10.11729/syltlx20230138.

高弗劳德数下绕锥头回转体通气空泡流态特征及压力脉动特性实验研究

Experimental study on the flow pattern and pressure fluctuation characteristics of ventilated cavitating flows around a conical axisymmetric body at high Froude number

  • 摘要: 本文基于循环水洞,采用高速摄影和压力传感器对绕锥头回转体通气空泡的流场特性进行了测量,重点讨论了高弗劳德数下通气空泡的流态特征以及不同空泡形态下回转体壁面的压力演化规律。研究结果表明:高弗劳德数下,重力效应可以忽略,绕锥头回转体通气空泡呈现出泡沫状(FC)、间歇透明状(ITC)和连续透明状(CTC)等三种典型的流态。其中,FC状空泡位于小通气率范围内,空泡末端以小尺度空泡团脱落为主,回转体壁面瞬态压力分布呈现出高频、低幅值脉动,压力系数最大脉动幅值为0.18;ITC状空泡为FC和CTC之间的过渡流态,空泡末端的大尺度空泡团脱落使得回转体壁面瞬态压力分布呈现出低频、高幅值脉动,压力系数最大脉动幅值为0.49;CTC状空泡位于大通气率范围内,空泡脱落以及压力脉动特性与ITC状空泡类似。特定的弗劳德数下,由FC逐渐转变为CTC的过程中,不同测点获得的回转体壁面压力都呈现出先减小后增大并稳定的趋势。

     

    Abstract: This paper is based on a circulating water tunnel, employing high-speed photography and pressure sensors to measure the flow characteristics of the ventilated cavity around a conical axisymmetric body. The focus of the discussion is on the flow characteristics of ventilated cavities at high Froude numbers and the pressure evolution on the axisymmetric body surface for different cavity shapes. The research results indicate that under high Froude numbers, gravity effects can be neglected, and ventilated cavities around the conical axisymmetric body exhibit three typical flow patterns: Foamy cavity (FC), Intermittent and Transparent cavity (ITC), and Continuous and Transparent cavity (CTC). Among these, FC cavities are found within a small ventilation rate range, accompanied by some small-scale cavity shedding at cavity’s trailing. The transient pressure distribution on the axisymmetric body surface exhibits high-frequency, low-amplitude fluctuations, with the maximum pressure coefficient fluctuation amplitude of 0.18. ITC cavities represent a transitional flow pattern between FC and CTC, characterized by the shedding of large-scale cavity clusters from the cavity’s trailing, resulting in low-frequency, high-amplitude fluctuations in the transient pressure distribution on the axisymmetric body surface, with a maximum pressure coefficient fluctuation amplitude of 0.49. CTC cavities are observed within a large ventilation rate range, exhibiting similar characteristics in cavity shedding and pressure pulsation to ITC cavities. Under specific Froude numbers, during the transition from FC to CTC, the pressure on the axisymmetric body surface at different measurement points exhibits a trend of initially decreasing, then increasing, and finally stabilizing.

     

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