The inception cavitating flows over an axisymmetric body with a blunt head- form

• Published in: Journal of hydrodynamics. Series B Vol. 27; no. 3; pp. 359 - 366
• Main Author: 胡常莉 王国玉 黄彪 赵宇
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2015; School of Mechanics and Vehicles,Beijing Institute of Technology,Beijing 100081,China
• Subjects: axisymmetric body; inception cavitation; PIV; turbulent fluctuations; vortex; 时间平均; 湍流流动; 演化过程; 空化流动; 粒子图像测速技术; 视频摄像机; 轴对称体; 速度场测量; vortex; PIV; turbulent fluctuations; axisymmetric body; inception cavitation
• ISSN: 1001-6058
• DOI: 10.1016/S1001-6058(15)60493-0

The inception cavitating flows around a blunt body are studied based on flow visualizations and velocity field measureme- nts. The main purpose of the present work is to study the incipient cavity evolution and the interplay between the inception cavitation and the local turbulent flows. A high-speed video camera is used to visualize the cavitating flow structures, and the particle image velocimetry （PIV） technique is used to measure the velocity field, the vorticity, and the Reynolds stresses under non-cavitating and inception cavitating flow conditions. It is found that the appearance of visible cavities is preceded by the formation of a cluster of micro-bubbles not attached to the body surface and in a hairpin-shaped vortex structure. During its evolution, the cavity moves downstream with a lower speed. The effect of the incipient cavity is significant on the local vortical structures but slight on the time- averaged velocity distribution. The mean Reynolds stress distributions in the turbulent shear flow can be substantially altered by the incipient cavities. The presence of the incipient cavities can lead to the production of turbulent fluctuations.