摘要
通过模型表面测压和油流显示,对旋成体于50°迎角在临界雷诺数区域（0.13×10^6~0.81×10^6）的压力分布和侧向力特性随雷诺数变化的演化规律进行了研究,结果表明,随着Re数从亚临界增加至临界区域,模型表面的低位涡侧首先出现层流分离气泡成为转捩分离（Tr）,而高位涡侧仍处于亚临界层流分离（L）,非对称更为显著,侧向力较亚临界区有所增加;随着雷诺数进一步增加,高位涡侧才成为转捩分离,此时非对称流动逐渐演变成对称流动,压力分布呈对称的平台状,侧向力明显减小,因此,通过流动分离前的压力恢复值作为判则,根据旋成体两侧边界层分别处于L/Tr和Tr/Tr状态,可将临界雷诺数区域划分为临界起始发展区和临界区。最后据此判则讨论了旋成体绕流沿轴向多种流态共存的现象。
An experimental study with pressure measurement and oil-flow visualization was conducted about evolution of the pressure and side force behaviors with variety of Reynolds number over an ogive-cylinder model in a range of Reynolds number from 0.13×10^6 to 0.81×10^6 at 50 degree angle of attack. The resuits showed that the transitional separation with separation bubbles first occurred on the lower vortex side with increasing Reynolds number into lower critical region, but the boundary layer on the higher vortex side remained the laminar separation. Comparing with that in subcritical region, the asymmetry of the flow is enlarged and the side force is larger. With increasing Reynolds number into upper critical region, the transitional separation also occurred on the higher vortex side and the asymmetric flow gradually became symmetric, the pressure distribution presented a symmetrically flat shape and the side force became much smaller, even approached to zero. So the initial critical regime and critical regime was found in the critical Reynolds number region based on the different separation pattern that is L/Tr and Tr/Tr on both sides of the slender body by using the criterion of pressure difference between separation point and minimum pressure point. Finally, the phenomenon of different separation types existing along the body axis was discussed based on the criterion.
出处
《空气动力学学报》
EI
CSCD
北大核心
2009年第5期529-535,共7页
Acta Aerodynamica Sinica
基金
国家自然科学基金(10432020)
航空科学基金(02A51048)
关键词
大迎角空气动力学
前体
非对称涡流动
Re数效应
aerodynamics at high angle of attack
forebody
asymmetric vortex flow
effect of Reynolds number
