Flow field measurement around vortex cavitation
Flow field measurement around vortex cavitation
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DOI：
10.1007/s00348-015-2073-9
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发表时间：
2015-11
影响因子：
2.4
通讯作者：
P. Pennings;J. Westerweel;T. V. Terwisga
中科院分区：
文献类型：
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作者：
P. Pennings;J. Westerweel;T. V. Terwisga
在螺旋桨周围的流动中，空泡涡引起的压力波动的中心频率的模型需要了解涡强度和蒸汽空腔尺寸。为此目的，立体粒子图像测速（PIV）测量下游的一个固定的半翼模型。需要高的空间分辨率，并通过相关平均获得。相对于传统的PIV测量，这将询问区域的尺寸减小了2-8倍。通过为给定的涡流位置选择PIV图像来解释涡流漂移，产生足够的数据以获得统计上收敛和准确的结果，无论是否有充满蒸汽的涡核。在此基础上，采用低阶普罗克特模型描述粘性核外的叶尖涡速度，以及空泡尺寸与空化数的关系。与无空化的流场相比，涡腔周围的流场显示出一个迟滞流区。空泡界面周围的这一层类似于无空泡的旋涡的粘性核。
Models for the center frequency of cavitating-vortex induced pressure-fluctuations, in a flow around propellers, require knowledge of the vortex strength and vapor cavity size. For this purpose, stereoscopic particle image velocimetry (PIV) measurements were taken downstream of a fixed half-wing model. A high spatial resolution is required and was obtained via correlation averaging. This reduces the interrogation area size by a factor of 2–8, with respect to conventional PIV measurements. Vortex wandering was accounted for by selecting PIV images for a given vortex position, yielding sufficient data to obtain statistically converged and accurate results, both with and without a vapor-filled vortex core. Based on these results, the low-order Proctor model was applied to describe the tip vortex velocity outside the viscous core, and the cavity size as a function of cavitation number. The flow field around the vortex cavity shows, in comparison with a flow field without cavitation, a region of retarded flow. This layer around the cavity interface is similar to the viscous core of a vortex without cavitation.