近超声速尾流中物体前面流动的特征规律性(英文)

在精心研究大量实验数据的基础上，确定出一对孤立物体之间的超声速湍流准则，从而得到诸参量的基本关联规律。有了这样的关联，就有可能计算出处于另一物体近尾流中的物体的热和力的效应。     

桥塔尾流致塔周长吊索涡振性能研究

悬索桥桥塔周围的长吊索自振频率较低,且易受桥塔尾流的干扰从而容易发生振动。吊索的安全直接关系着桥梁结构的安全,以实际工程为背景,采用CFD数值模拟方法并选择SST k-ω湍流模型对二维桥塔断面及吊索断面的非定常绕流进行了分析。首先,计算了桥塔和吊索各自的气动特性,并与相关文献的结果进行了对比。在验证分析方法可靠性的基础上,进一步研究了不同来流风速、风向角下,桥塔尾流对塔周长吊索气动特性的干扰。通过对流场特征及吊索气动力的变化规律进行分析,研究了桥塔尾流作用下塔周长吊索发生涡振的可能性。研究结果表明:在相当大的风向角范围内,桥塔脱落的旋涡会对吊索气动特性产生控制作用,从而导致吊索阻力系数和升力系数的变化频率等于桥塔的旋涡脱落频率,使吊索在低风速下存在发生涡激共振的可能性。     

Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller

Swirl recovery vanes（SRVs） are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise to a promotion in propulsive performance of this traditional propeller. Firstly the numerical strategy is validated from two aspects of global quantities and the local flow field of the propeller compared with experimental data, and then the exit flow together with the development of propeller wake is analyzed in detail.Three kinds of SRV are designed with multiple circular airfoils. The numerical results show that the swirl behind the propeller is recovered significantly with Model V3, which is characterized by the highest solidity along spanwise, for various working conditions, and the combination of rotor and vane produced 5.76% extra thrust at the design point. However, a lower efficiency is observed asking for a better vane design and the choice of a working point. The vane position is studied which shows that there is an optimum range for higher thrust and efficiency.     

旋涡破裂对单独翼气动特性的影响及其工程估算方法

本文介绍了旋涡破裂对单独翼纵向和横向气动特性的影响,在分析和归纳实验数据的基础上,提出估算旋涡破裂对单独翼纵向和横向气动特性影响的工程方法。     

不良流线体的减阻新概念

介绍了一种不良流线体减阻的新概念,在物体迎风面上适当位置安装适当尺寸的侧板,可以将阻力减少80％以上,从而为这类物体减阻提供了新思路。     

空中交通中尾流间隔的研究

分析了雷达尾流间隔标准的分类，通过尾流的形成机理和对后机影响的分析，建立了后机的危险遭遇模型和前机的尾流消散模型，给出了在确定的时间间隔下确定尾流危险遭遇概率的方法。     

钝体近尾流区的流动特性

本文介绍了对钝体近尾流的时间平均流动特性进行试验研究的结果。试验中分别以圆柱体和三棱柱体为模型,考虑了几何形状和雷诺数对流动结构的影响。试验结果表明,对于高雷诺数情况,在“死水区”内,存在着与低雷诺数情况下类似的时间平均流动特性。最后,对尾流中涡街形成的机理进行了初步讨论。