湍流角区三维分离空间与表面流动结构研究

发布时间：2018-01-27 08:18

本文关键词： 湍流角区表面油流流动显示 PIV 分离线低剪切应力线　出处：《空气动力学学报》2017年02期 　论文类型：期刊论文

【摘要】：针对湍流角区三维分离流动中表面油流图画(油流显示)出现的差异和不同性质,综合采用表面油流流动显示、空间PIV实验以及数值模拟探究不同表面流动结构的性质、产生差异的原因及其与空间流动结构的关系。研究表明,较强分离情况下表面油流呈现的两条油流线均为三维分离线,即一次分离线(上游)与二次分离线(下游)。油流线是空间非定常流动的时均结果,空间非定常流动以四涡结构为主。一次分离线(上游)符合Lighthill的收拢渐进线三维分离模式,二次分离线(下游)则符合Maskell的包络线三维分离模式。由于较强的第一主涡和二次涡在近壁面产生强剪切,二次分离线体现出与一次分离线不同的狭窄而清晰的油迹堆积以及低剪切应力特征,因此二次分离线又可称为低剪切应力线。在低剪切应力线两侧是由第一主涡和二次涡引起的较高剪切应力区。
[Abstract]:In view of the difference and different properties of surface oil flow picture (oil flow display) in three dimensional separation flow in turbulent angle region, the surface oil flow display is used synthetically. The spatial PIV experiment and numerical simulation are used to study the properties of different surface flow structures, the causes of the differences and their relationship with spatial flow structures. In the case of strong separation, the two oil streamline lines on the surface are both three dimensional separation lines, namely, the primary separation line (upstream) and the secondary separation line (downstream). The oil streamline is the time-averaged result of the spatial unsteady flow. The spatial unsteady flow is mainly composed of four vortices. The primary separation line (upstream) accords with Lighthill's three-dimension separation model of closed and progressive lines. The secondary separation line (downstream) is consistent with Maskell's envelope three-dimensional separation model. The strong first main vortex and secondary vortex produce strong shear near the wall. The secondary separation line shows the characteristics of narrow and clear oil accumulation and low shear stress different from the primary separation line. Therefore, the secondary separation line is also called the low shear stress line, and the higher shear stress region is caused by the first main vortex and the secondary vortex on both sides of the low shear stress line.
【作者单位】：北京航空航天大学航空科学与工程学院;
【基金】：国家自然科学基金(11372027)
【分类号】：V211
【正文快照】： 0引言湍流角区流动广泛地存在于流体力学与空气动力学工程应用中,多年来国内外专家学者对其做了大量的研究工作,取得了很多研究成果,也发现了一些问题。Hunt et al[1]、Baker[2]、Dargahi[3]、Pierce与Shin[4]、Pattenden[5]和Simpson[6]等学者都对角区障碍物周围油流流动进行

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