The unsteady flows produced over the stern of a Simple Frigate Shape 2 ship model are studied in a low-speed wind tunnel. Time-resolved particle image velocimetry (TR-PIV) measurements were performed in several streamwise and cross planes. Two grids of Cowdrey rods were used to simulate the basic characteristics of an atmospheric boundary layer in terms of upstream velocity profile and turbulence intensity. The TR-PIV measurements showed large regions of unsteady flow separation, dominant vortical flows, and significant wall-normal flows over the flight deck regions caused, in part, by the irregular shedding of vorticity and turbulence from the upstream funnel and superstructure of the ship. Turbulence intensities were found to be particularly high over the flight deck. The measured flows also suggested the existence of asymmetric, intermittent flow in the near-wall regions of the deck, and time-varying fluctuations in the recirculation region behind the hangar. The crossplane measurements showed the development of shear layers at the corners of the flight deck on both the port and starboard sides, and sets of counterrotating vortices at the edges of the flight deck. An energy spectrum analysis showed dominant frequencies in the regions where the shear layer was developed behind the funnel and above the flight deck. Spectral proper orthogonal decomposition revealed that the physically relevant coherent structures in the airwake were low-frequency modes near the flight deck and at large-scale of the order of the length of the deck.

在低速风洞中研究了简单护卫舰Shape 2船模型的船尾产生的非定常流动。时间分辨粒子图像测速（TR-PIV）测量在多个流向和交叉平面中进行。根据上游速度分布和湍流强度，使用了两个格子的考德瑞棒来模拟大气边界层的基本特征。TR-PIV测量显示出大面积的不稳定流动分离，主要的涡流以及驾驶舱区域上显着的壁面法向流动，部分原因是上游漏斗和船舶上层结构的涡流和湍流不规则脱落。发现驾驶舱内的湍流强度特别高。测得的流量还表明存在不对称，甲板近壁区域中的间歇性流动，以及机库后面的再循环区域中的时变波动。横断面测量显示左舷和右舷两侧驾驶舱角处的剪切层的发展，以及驾驶舱边缘处的一组反向旋涡。能量谱分析显示在漏斗后面和驾驶舱上方剪切层形成的区域中的主导频率。光谱固有的正交分解表明，空中苏醒中与物理相关的相干结构是驾驶舱附近的低频模式，并且是驾驶舱长度的大尺度。横断面测量显示左舷和右舷两侧驾驶舱角处的剪切层的发展，以及驾驶舱边缘处的一组反向旋涡。能量谱分析显示在漏斗后面和驾驶舱上方剪切层形成的区域中的主导频率。光谱固有的正交分解表明，空中苏醒中与物理相关的相干结构是驾驶舱附近的低频模式，并且是驾驶舱长度的大尺度。横断面测量显示左舷和右舷两侧驾驶舱角处的剪切层的发展，以及驾驶舱边缘处的一组反向旋涡。能量谱分析显示在漏斗后面和驾驶舱上方剪切层形成的区域中的主导频率。光谱固有的正交分解表明，空中苏醒中与物理相关的相干结构是驾驶舱附近的低频模式，并且是驾驶舱长度的大尺度。能量谱分析显示在漏斗后面和驾驶舱上方剪切层形成的区域中的主导频率。光谱固有的正交分解表明，空中苏醒中与物理相关的相干结构是驾驶舱附近的低频模式，并且是驾驶舱长度的大尺度。能量谱分析显示在漏斗后面和驾驶舱上方剪切层形成的区域中的主导频率。光谱固有的正交分解表明，空中苏醒中与物理相关的相干结构是驾驶舱附近的低频模式，并且是驾驶舱长度的大尺度。