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Effect of vortex dynamics and instability characteristics on the induced drag of trailing vortices

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Chinese Journal of Aeronautics 2022年第9期35卷 160-173页

作者： Zepeng CHENG Shiyan ZHANG Yang XIANG Chun SHAO Miao ZHANG Hong LIU Yingchun CHEN School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

In this paper, trailing vortices generated by three wingtip configurations, namely the M6wing and the M6 wing with a blended or split winglet, are experimentally investigated using the Stereo Particle Image Velocimetry(spiv) technology. Then, linear stability analysis is performed to investigate instability characteristics. Three corresponding trailing vortex patterns, including the isolated trailing vortex without wake(pattern v) and with wake(pattern v-w), co-rotating vortex pair(pattern v-v), are observed in experiments. The strength of trailing vortices, characterized by circulation, is reduced after installing winglets as expected, and the strength of pattern v-v can be further suppressed compared with pattern v-w. Moreover, instability characteristics, such as the eigenvalue spectrum and perturbation mode, are distinctive among these three vortex patterns.The distribution of eigenvalue spectrums indicates that pattern v and pattern v-w are temporally“marginally stable”, while pattern v-v is temporally “unstable.” The primary perturbation mode of pattern v and pattern v-w is the m =-1 helical mode, while |m|>1 for the case of pattern v-v.The effect of vortex dynamics and instability characteristics can be concluded in two aspects.Firstly, the value of induced drag is polluted by about 3% from vortex wandering since vortex wandering affects the tangential velocity and streamwise vorticity of trailing vortices. Secondly, the growth rate and penetration depth perturbation mode affect trailing vortex evolution and further affect induced drag. Specifically, the larger the growth rate and penetration depth are, the more turbulence injects inside the vortex core, thus leading to a quicker and more intense attenuation of trailing vortex, as well as a smaller induced drag. This finding can guide us to manipulate the induced drag in flow control.

关键词： Induced drag Linear stability analysis spiv Trailing vortex Vortex flow Winglet

Experimental Investigation of Effects of Suction-Side Squealer Tip Geometry on the Flow Field in a Large-scale Axial Compressor using spiv

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Journal of Thermal Science 2015年第4期24卷 303-312页

作者： MA Hongwei WEI Wei WANG Lixiang TIAN Yangtao Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power Engineering Beihang University Collaborative Innovation Center of Advanced Aero-Engine

It is well known that the non-uniform tip geometry is a promising passive flow control technique in turbomachinery.However,detailed investigation of its effects on the unsteady flow field of turbomachinery is rare in the existiug hteratures.This paper presents an experimental investigation of effects of suction side squealer tip configuration on both the steady and unsteady flow field of an isolated compressor rotor.The flow field at 10%chord downstream from the trailing edge was measured using a mini five-hole probe.Meanwhile,the unsteady flow field inside the passage was investigated using stereo particle image velocimetry(spiv).The steady results show that the SSQ tip configuration exerts positive effect on the static pressure rise performance of this compressor,and the radial equilibrium at the rotor outlet is obviously rearranged.The SSQ tip configuration would create a stronger tip leakage vortex at the formation phase,and it experiences a faster dissipation process around the rear chord.Also,the splitting process of the tip leakage vortex is severer,which is the main cause of the relatively higher probability of the presence of the streamwise reverse flow.The quantitatively analysis of the tip leakage vortex indicates that the velocity loss inside the blockage region is direct response of the evolutionary procedure of the tip leakage vortex.It keeps increasing until the end of the splitting process.Although the blockage coefficient grows sustainably,the velocity loss will reduce once the turbulent mixing procedure is dominant.

关键词：轴流压缩机 spiv 影响实验对流场几何声响叶尖泄漏涡粒子图像测速技术

Experimental investigation of flow field in a laboratory-scale compressor

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Chinese Journal of Aeronautics 2017年第1期30卷 31-46页

作者： Ma Hongwei Wei Wei Xavier Ottavy Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power Engineering Beihang University Beijing 100083 China Collaborative Innovation Center of Advanced Aero-Engine Beijing 100083 China China Academy of Aerospace Aerodynamics (CAAA) Yungangxi Rd. Fengtai Dist. Beijing 100074 China Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA) Groupe TurbomachinesEcole Centrale de Lyon 36 av. Guy de Collongue 69134 Ecully cedex France

The inner flow environment of turbomachinery presents strong three-dimensional, rotational, and unsteady characteristics. Consequently, a deep understanding of these flow phenomena will be the prerequisite to establish a state-of-the-art design system of turbomachinery. Currently the development of more accurate turbulence models and CFD tools is in urgent need for a high-quality database for validation, especially the advanced CFD tools, such as large eddy simulation（LES）. Under this circumstance, this paper presents a detailed experimental investigation on the 3D unsteady flow field inside a laboratory-scale isolated-rotor with multiple advanced measurement techniques, including traditional aerodynamic probes, hotwire probes, unsteady endwall static pressure measurement, and stereo particle image velocimetry（spiv）. The inlet boundary layer profile is measured with both hotwire probe and aerodynamic probe. The steady and unsteady flow fields at the outlet of the rotor are measured with a mini five-hole probe and a single-slanted hotwire probe. The instantaneous flow field in the rotor tip region inside the passage is captured with spiv,and then a statistical analysis of the spatial distribution of the instantaneous tip leakage vortex/flow is performed to understand its dynamic characteristics. Besides these, the uncertainty analysis of each measurement technique is described. This database is quite sufficient to validate the advanced numerical simulation with LES. The identification process of the tip leakage vortex core in the instantaneous frames obtained from spiv is performed deliberately. It is concluded that the ensemble-averaged flow field could not represent the tip leakage vortex strength and the trajectory trace. The development of the tip leakage vortex could be clearly cataloged into three phasesaccording to their statistical spatial distribution. The streamwise velocity loss induced by the tip leakage flow increases until the splitting process is weak and the turbulent mixing phase is dominant.

关键词： Database Laboratory-scale compres-sor spiv Tip leakage flow Tip leakage vortex

Experimental measurement of tip vortex flow field with/without cavitation in an elliptic hydrofoil

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Journal of Hydrodynamics 2017年第6期29卷 939-953页

作者：彭晓星徐良浩刘玉文张国平曹彦涛洪方文颜开 National Key Laboratory on Ship Vibration and Noise China Ship Scientific Research CenterWuxi 214082China

In this paper, recent measurements of tip vortex flow with and without cavitation carried out in Cavitation Mechanism Tunnel of China Ship Scientific Research Center（CSSRC） are presented. The elliptic hydrofoil with section NACA 662-415 was adopted as test model. High-speed video（HSV） camera was used to visualize the trajectory of tip vortex core and the form of tip vortex cavitation（TVC） in different cavitation situations. Laser Doppler velocimetry（LDV） was employed to measure the tip vortex flow field in some typical sections along the vortex trajectory with the case of cavitation free. Stereo particle image velocimetry（spiv） system was used to measure the velocity and vorticity distributions with and without cavitation. Series measurement results such as velocity and vorticity distributions, the trajectory of tip vortex core, the vortex core radius, cavity size and cavitation inception number were obtained. The results demonstrated that the minimum pressure coefficient in the vortex core obtained by flow field measurement was quite coincident with the tip vortex cavitation inception number obtained under the condition of high incoming velocity and low air content. And TVC would decrease the vortex strength comparing with the case without cavitation.

关键词： Tip vortex flow field cavitation LDV spiv HSV measurement data

Instability characteristics of a co-rotating wingtip vortex pair based on bi-global linear stability analysis

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Chinese Journal of Aeronautics 2021年第5期34卷 1-16页

作者： Zepeng CHENG Siyi QIU Yang XIANG Chun SHAO Miao ZHANG Hong LIU School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

The Stereo Particle Image Velocimetry(spiv)technology is applied to measure the wingtip vortices generated by the up-down symmetrical split winglet.Then,the temporal biglobal Linear Stability Analysis(bi-global LSA)is performed on this nearly equal-strength corotating vortex pair,which is composed of an upper vortex(vortex-u)and a down vortex(vortex-d).The results show that the instability eigenvalue spectrum illustrated by(ωr,ω_(i))contains two types of branches:discrete branch and continuous branch.The discrete branch contains the primary branches of vortex-u and vortex-d,the secondary branch of vortex-d and coupled branch,of which all of the eigenvalues are located in the unstable half-plane ofω_(i)>0,indicating that the wingtip vortex pair is temporally unstable.By contrast,the eigenvalues of the continuous branch are concentrated on the half-plane ofω_(i)<0 and the perturbation modes correspond to the freestream perturbation.In the primary branches of vortex-u and vortex-d,Mode P_(u) and Mode Pd are the primary perturbation modes,which exhibit the structures enclosed with azimuthal wavenumber m and radial wavenumber n,respectively.Besides,the results of stability curves for vortex-u and vortex-d demonstrate that the instability growth rates of vortex-u are larger than those of vortex-d,and the perturbation energy of Mode P_(u) is also larger than that of Mode Pd.Moreover,the perturbation energy of Mode P_(u) is up to 0.02650 and accounts for 33.56%percent in the corresponding branch,thereby indicating that the instability development of wingtip vortex is dominated by Mode P_(u).By further investigating the topological structures of Mode P_(u) and Mode Pd with streamwise wavenumbers,the most unstable perturbation mode with a large azimuthal wavenumber of m=5-6 is identified,which imposes on the entire core region of vortex-u.This large azimuthal wavenumber perturbation mode can suggest the potential physical-based flow control strategy by manipulating it.

关键词： Bi-global linear stability analysis Perturbation mode spiv Vortex flow Winglet Wingtip vortex

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用spiv技术测量压气机转子尖区复杂流动

工程热物理学报 2003年第4期24卷 575-578页

作者：于宏军刘宝杰蒋浩康袁辉靖徐月亭北京航空航天大学动力系404教研室北京100083 北京大学力学与工程科学系北京100085

本文将数字式spiv技术应用到低速大尺寸压气机实验台上,并在设计状态和近失速状态下,对转子槽道内叶尖区域多个截面内的三维瞬态速度场进行了成功测量。测量结果表明spiv透过机匣视窗及即可直接测量旋涡和二次流的瞬态结构,而且能够解... 详细信息

本文将数字式spiv技术应用到低速大尺寸压气机实验台上,并在设计状态和近失速状态下,对转子槽道内叶尖区域多个截面内的三维瞬态速度场进行了成功测量。测量结果表明spiv透过机匣视窗及即可直接测量旋涡和二次流的瞬态结构,而且能够解决多级压气机内部流场的测量.在压气机spiv测量中,激光反光的控制和示踪粒子的均匀稳定散播是决定成败的关键因素。

关键词： spiv 压气机叶尖泄漏流角区旋涡非定常流

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飞机尾流控制的spiv实验研究

实验流体力学 2009年第1期23卷 18-22页

作者：黄烁桥申功炘 Robert Konrath Carl F.v. Carmer Kompenhans Jürgen 北京航空航天大学航空科学与工程学院流体所北京100191 Institute of Aerodynamics and Flow Technology Germany Aerospace Center (DLR) Gottingen Germany

利用简化的飞机模型,通过改变尾翼的迎角及展弦比,试图建立一种能加速自我消亡的尾流涡系统。该实验在拖曳水槽中进行,运用spiv(体视粒子图像测速技术)系统进行测量,获得了一系列空间切面的2D/3C(二维/三分量)数据,给出了三种不同尾翼情... 详细信息

利用简化的飞机模型,通过改变尾翼的迎角及展弦比,试图建立一种能加速自我消亡的尾流涡系统。该实验在拖曳水槽中进行,运用spiv(体视粒子图像测速技术)系统进行测量,获得了一系列空间切面的2D/3C(二维/三分量)数据,给出了三种不同尾翼情况(两种有尾翼情况及一种无尾翼情况)下的spiv观测结果,并将这几种情况作了对比。

关键词：尾流涡 spiv Rayleigh-Ludwieg不稳定性飞机模型水槽

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孤立翼尖涡模态演化规律的实验研究

航空学报 2023年第11期44卷 118-134页

作者：吴奕铭邱思逸向阳刘洪上海交通大学航空航天学院上海200240

采用主动流动控制方法加快翼尖涡衰减破碎是提升机场起降频率、保证飞机飞行安全的最具潜力的技术之一。由于翼尖涡不稳定性认识的不足,已有的主动控制方法常常不能获得最优的控制效果。为了揭示翼尖涡不稳定模态的演化规律,采用体视粒... 详细信息

采用主动流动控制方法加快翼尖涡衰减破碎是提升机场起降频率、保证飞机飞行安全的最具潜力的技术之一。由于翼尖涡不稳定性认识的不足,已有的主动控制方法常常不能获得最优的控制效果。为了揭示翼尖涡不稳定模态的演化规律,采用体视粒子图像测速技术和线性稳定性分析方法对孤立翼尖涡的不稳定模态演化特征进行研究,结果表明:孤立翼尖涡的扰动模态可以根据其在特征值谱的位置分成主扰动模态、P族次级扰动模态、A族次级扰动模态、S族次级扰动模态4种;其中主扰动模态和P族扰动模态具有两瓣式的结构特征,决定了翼尖涡摇摆的各向异性特征,A族次级扰动模态具有流向速度波动大于横向速度波动的特征,S族次级扰动模态则具有更高的切向波数和作用范围。不同族扰动模态的流向演化规律不同,翼尖涡的主扰动模态和P族扰动模态沿流向发生旋转,并且扰动幅值随着流向逐渐放大,A族次级扰动模态随着流向发展会逐渐增大扰动幅值;S族次级扰动模态随着流向会逐渐覆盖住整个涡核,这种穿透涡核的扰动会随着流向进一步放大。描述了不同翼尖涡扰动模态的扰动能量随流向的演化规律,发现S族次级扰动模态有更高的切向波数特征,也同时具有较高的扰动能量增长,意味着利用S族次级扰动模态指导翼尖涡主动控制是最具潜力的一种策略。

关键词： spiv 翼尖涡涡不稳定性线性稳定性分析扰动模态

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近失速状态下压气机转子叶尖旋涡流动研究

航空学报 2004年第1期25卷 9-15页

作者：于宏军刘宝杰刘火星蒋浩康北京航空航天大学能源与动力工程学院北京100083

在低速大尺寸单级压气机实验台上,利用spiv技术测量了近失速状态下压气机转子尖区多个截面的三维瞬态速度场。基于瞬态场测量结果,详细阐述了近失速状态下压气机转子叶尖泄漏涡的演化过程和角区旋涡的形成过程。测量结果表明角区旋涡是... 详细信息

在低速大尺寸单级压气机实验台上,利用spiv技术测量了近失速状态下压气机转子尖区多个截面的三维瞬态速度场。基于瞬态场测量结果,详细阐述了近失速状态下压气机转子叶尖泄漏涡的演化过程和角区旋涡的形成过程。测量结果表明角区旋涡是一种总体意义上的旋涡,其涡核是由多个涡团组成的,形成角区旋涡的一个关键机制是压气机的旋转运动对源于近吸力面的正负涡量的涡团具有选择性。

关键词：角区旋涡叶尖泄漏涡非定常相互作用 spiv 压气机