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A STUDY OF THE ROTOR WAKE IN NAP-OF-THE-EARTH
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《Chinese Journal of Aeronautics》 SCIE EI CAS 1988年第2期71-78,共8页
In this paper an investigation of the ground vortex,the significant aerodynamic phenomenon in rotor aerodynamics on nap-of-the- earth,is carried out.Based on the analysis of the rotor wake near the ground,a theoretica... In this paper an investigation of the ground vortex,the significant aerodynamic phenomenon in rotor aerodynamics on nap-of-the- earth,is carried out.Based on the analysis of the rotor wake near the ground,a theoretical method has been established which can be used for calculating the ground vortex—its longitudinal position and strength.The computational results are compared with avaUable experimental data and found in good agreement. 展开更多
关键词 A STUDY OF THE rotor wake IN NAP-OF-THE-EARTH NAP
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New Progress in Helicopter Rotor Wake Research
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作者 XU Guohua SHI Yongjie ZHAO Qijun 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第1期36-56,共21页
Rotor wake analysis,a fundamental research of helicopter technology,has been widely applied for rotor aerodynamic analysis. This paper summarizes the research of different rotor wake models at home and abroad and revi... Rotor wake analysis,a fundamental research of helicopter technology,has been widely applied for rotor aerodynamic analysis. This paper summarizes the research of different rotor wake models at home and abroad and reviews the development process of rotor wake methods as well as the research achievement obtained in each stage.Then,the new progress of helicopter rotor wake methods is described in detail. It includes constant circulation contours modeling method of rotor wake,pseudo-implicit relaxation iteration and time-accurate solution method,research on aerodynamic interaction characteristics of helicopter rotor/fuselage by wake method,research on the rotor blade-vortex interaction noise and interaction of coaxial rigid rotor aerodynamics by viscous vortex particle method,and application of free wake method to helicopter flight dynamics modeling. In the end,some prospects for the research of helicopter rotor wake method are put forward,which clarifies the ideas for the future development of rotor wake method. 展开更多
关键词 HELICOPTER rotor free wake VISCOUS VORTEX particles aerodynamic characteristics FLIGHT dynamics wake progress
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Rotor wake capture improvement based on high-order spatially accurate schemes and chimera grids
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作者 徐丽 翁培奋 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第12期1565-1576,共12页
A high-order upwind scheme has been developed to capture the vortex wake of a helicopter rotor in the hover based on chimera grids. In this paper, an improved fifth-order weighted essentially non-oscillatory (WENO) ... A high-order upwind scheme has been developed to capture the vortex wake of a helicopter rotor in the hover based on chimera grids. In this paper, an improved fifth-order weighted essentially non-oscillatory (WENO) scheme is adopted to interpolate the higher-order left and right states across a cell interface with the Roe Riemann solver updating inviscid flux, and is compared with the monotone upwind scheme for scalar conservation laws (MUSCL). For profitably capturing the wake and enforcing the period boundary condition, the computation regions of flows are discretized by using the struc- tured chimera grids composed of a fine rotor grid and a cylindrical background grid. In the background grid, the mesh cells located in the wake regions are refined after the so- lution reaches the approximate convergence. Considering the interpolation characteristic of the WENO scheme, three layers of the hole boundary and the interpolation boundary are searched. The performance of the schemes is investigated in a transonic flow and a subsonic flow around the hovering rotor. The results reveal that the present approach has great capabilities in capturing the vortex wake with high resolution, and the WENO scheme has much lower numerical dissipation in comparison with the MUSCL scheme. 展开更多
关键词 hovering rotor vortex wake Navier-Stokes equation chimera grid weightedessentially non-oscillatory (WENO) scheme
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EXPERIMENTAL INVESTIGATION OF AERODYNAMICINTERACTION EFFECT OF ROTOR WAKE ONFUSELAGE OF HELICOPTER
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作者 徐锦法 高正 梅卫胜 《Chinese Journal of Aeronautics》 SCIE EI CSCD 2000年第1期1-7,共7页
The interaction effect of rotor wake on fuselage of helicopter was investigated with experimental method. The results from experiment have proved that for the drag of fuselage the effect of rotor airflow is closely in... The interaction effect of rotor wake on fuselage of helicopter was investigated with experimental method. The results from experiment have proved that for the drag of fuselage the effect of rotor airflow is closely in connection with both the flight speed and the collective pitch of blades, while for the thrust and pitch moment of fuselage the collective pitch angle of blades plays more important role. A simple and effective computing method about aerodynamic interaction can be derived from the measured data. In order to implement the experiment, a fuselage model, a special sensor, the measurement and data acquisition and processing system were designed and manufactured according to the special requirements of this research project, thereby a good base was built up for carrying out experiments successfully with high quality. 展开更多
关键词 Aerodynamic loads Computational methods Data acquisition Drag Fuselages Helicopter rotors Mathematical models SENSORS wakeS
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Numerical Simulation of the Wake Generated by a Helicopter Rotor in Icing Conditions 被引量:2
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作者 Guozhi Li Yihua Cao 《Fluid Dynamics & Materials Processing》 EI 2021年第2期235-252,共18页
The wake generated by the rotor of a helicopter can exert a strong interference effect on the fuselage and the horizontal/vertical tail.The occurrence of icing on the rotor can obviously make this interplay more compl... The wake generated by the rotor of a helicopter can exert a strong interference effect on the fuselage and the horizontal/vertical tail.The occurrence of icing on the rotor can obviously make this interplay more complex.In the present study,numerical simulation is used to analyze the rotor wake in icing conditions.In order to validate the overall mathematical/numerical method,the results are compared with similar data relating to other tests;then,different simulations are conducted considering helicopter forward flight velocities of 0,10,20,50,and 80 knots and various conditions in terms of air temperature(atmospheric temperature degrading from−12°C to−20°C or from−20°C to−26°C).The results indicate that the rotor aerodynamic performance(i.e.,the lift-to-drag ratio distribution of the rotor disc)drops significantly once the rotor undergoes ice accretion.More importantly,the icing exerts a different influence of the wake dynamics depending on the atmospheric conditions.Interestingly,the rime-ice firstly occurs on the inner portion of rotor blades and then diffuses outward along the blade radial direction with the decrease in atmospheric temperature. 展开更多
关键词 Numerical simulation HELICOPTER rotor wake ice accretion
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WAKE GEOMETRY CALCULATIONS FOR TILT-ROTOR USING VISCOUS VORTEX METHOD
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作者 魏鹏 史勇杰 徐国华 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2013年第4期297-305,共9页
A tilt-rotor unsteady flow analytical method has been developed based upon viscous vortex-particle method.In this method,the vorticity field is divided into small assembled vortex particles.Vortex motion and diffusion... A tilt-rotor unsteady flow analytical method has been developed based upon viscous vortex-particle method.In this method,the vorticity field is divided into small assembled vortex particles.Vortex motion and diffusion are obtained by solving the velocity-vorticity-formed incompressible Navier-Stokes equations using agrid-free Lagrangian simulation method.Generation of the newly vortex particles is calculated by using the Weissinger-L lifting surface model.Furthermore,in order to significantly improve computational efficiency,a fast multiple method(FMM)is introduced into the calculation of induced velocity and its gradient.Finally,the joint vertical experimental(JVX)tilt-rotor is taken as numerical examples to analyze.The wake geometry and downwash are investigated for both hover and airplane modes.The proposed method for tilt-rotor flow analysis is verified by comparing its results with those available measured data.Comparison indicates that the current method can accurately capture the complicated tilt-rotor wake variation and be suitable for aerodynamic interaction simulation in complex environments.Additionally,the aerodynamic interactional characteristics of dual-rotor wake are discussed in different rotor distance.Results show that there are significant differences on interactional characteristics between hover mode and airplane mode. 展开更多
关键词 tilt-rotor rotor wake viscous vortex method aerodynamic interaction
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CALCULATION OF HELICOPTER ROTOR FLAPPING ANGLESAND COMPARISON WITH MEASURED DATA
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作者 赵景根 徐国华 王适存 《Chinese Journal of Aeronautics》 SCIE EI CSCD 2000年第2期75-79,共5页
Helicopter rotor flapping angles from hover to low speed forward flight are calculated and compared with the measured data in this paper. The analytical method is based on a second order lifting line/full span free... Helicopter rotor flapping angles from hover to low speed forward flight are calculated and compared with the measured data in this paper. The analytical method is based on a second order lifting line/full span free wake model as well as a fully coupled rotor trim model. It is shown that, in order to accurately predict the lateral flapping angle at low advance ratio, it is necessary to use free wake analysis to account for the highly non uniform inflow induced by the distorted wake geometry at rotor disc plane. 展开更多
关键词 helicopters rotor aerodynamics rotor wakes flapping motion rotor trim
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Numerical Simulation of Rotor Clocking Effect in a Low-Speed Compressor 被引量:5
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作者 杨海涛 黄洪雁 +2 位作者 冯国泰 苏杰先 孙维荣 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2003年第3期129-137,共9页
Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows tha... Two-dimensional (2D) unsteady numerical simulation has been applied to studythe effect of the variation in relative circumferential positions of rotors on the performance of alow speed compressor. The result shows that the variation will change the relative position ofupstream rotor wake to the downstream rotor as well as the periodic and turbulent velocityfluctuations on the airfoils. When the upstream rotor wake impinges upon the leading edge of thedownstream rotor, the corresponding stage efficiency will be higher; when the upstream wake istransferred into the mid-passage of the downstream rotor, the corresponding stage efficiency will belower. The proper configuration of the relative position of rotors will cause obvious reduction inthe unsteady aerodynamic effect on the second rotor airfoils and improve the aerodynamic performanceof blades. 展开更多
关键词 COMPRESSOR UNSTEADY rotor wake INTERACTION
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Internal Flow Condition between Front and Rear Rotor of Contra-Rotating Small-Sized Axial Fan at Low Flow Rate
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作者 Toru Shigemitsu Kensuke Tanaka +1 位作者 Katsuhiko Hirosawa Keisuke Miyazaki 《Open Journal of Fluid Dynamics》 2017年第4期709-723,共15页
Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at th... Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at the low flow rate. Furthermore, the blade row distance between the front and rear rotors is an important parameter for the contra-rotating small-sized fan and its influence on the internal flow condition is not clarified at the low flow rate. Therefore, the internal flow condition of the contra-rotating small-sized fan at the low flow rate is investigated by the numerical analysis in this research. The numerical analysis results are validated by comparing the fan static pressure curves of the numerical results to the experimental results. The internal flow condition at the low flow rate is clarified using the numerical models of the different blade row distance L = 10 mm and 30 mm. In the present paper, pressure fluctuations phase locked each front and rear rotor’s rotation are shown and the influences of the wake and the potential interference are discussed by the unsteady numerical analysis results at the low flow rate. 展开更多
关键词 Small-Sized AXIAL FAN Contra-Rotating rotors wake Potential Interference Numerical Analysis
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不同前倾角度倾转旋翼噪声数值计算分析
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作者 袁明川 孙会迅 +2 位作者 李志彬 牛青峰 樊枫 《西北工业大学学报》 EI CAS CSCD 北大核心 2024年第2期205-213,共9页
基于自由尾迹结合FW-H(Ffowcs Williams-Hawkings)方程的方法建立了倾转旋翼气动噪声计算模型,并采用倾转旋翼模型噪声试验数据验证了计算分析方法的有效性。选取典型过渡路径,进行考虑配平的倾转双旋翼气动噪声特性计算,获得了旋翼桨... 基于自由尾迹结合FW-H(Ffowcs Williams-Hawkings)方程的方法建立了倾转旋翼气动噪声计算模型,并采用倾转旋翼模型噪声试验数据验证了计算分析方法的有效性。选取典型过渡路径,进行考虑配平的倾转双旋翼气动噪声特性计算,获得了旋翼桨叶剖面非定常气动载荷以及不同测点气动噪声等计算结果,分析了倾转旋翼在不同前倾角下噪声指向性和噪声声压级的变化。结果表明:由于双旋翼噪声在传播中的叠加和抵消,倾转双旋翼和孤立单旋翼的噪声指向特性存在较大的不同;倾转旋翼噪声随前倾角增加总体上呈现先增加后减小的变化趋势,在前倾角30°附近噪声最强;不同前倾角下噪声声压级和指向性的变化与旋翼桨尖马赫数、气动载荷和桨盘角度等多种因素相关。 展开更多
关键词 倾转旋翼 气动噪声 倾转角度 自由尾迹 FW-H方程
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Savonius型转轮三角阵列减流性能研究
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作者 王声虎 姜楚华 +2 位作者 陈俊华 李浩 吴思儒 《海洋科学》 CAS CSCD 北大核心 2024年第3期64-74,共11页
为了助力海洋牧场减流防护工程,研究Savonius型转轮阵列减流性能。作者建立Savonius型转轮三角阵列尾流场数值模型,并通过水池实验验证准确性,基于可靠数值模型探究转轮阵列尾涡减流机理,研究三角阵列结构参数LX、LY,以及动力参数TSR、... 为了助力海洋牧场减流防护工程,研究Savonius型转轮阵列减流性能。作者建立Savonius型转轮三角阵列尾流场数值模型,并通过水池实验验证准确性,基于可靠数值模型探究转轮阵列尾涡减流机理,研究三角阵列结构参数LX、LY,以及动力参数TSR、初始流速、旋向对整体减流性能的影响规律。结果表明,下游转轮产生的涡流呈现非对称分布,并且产生更多涡流的转轮拥有更好的减流效果。另外,LX为3D和LY为2D时减流性能最佳。最后对比发现,在叶尖速比为0.9~1.1减流效果更好;初始流速大小不影响减流效果;下游转子对称分布时,随着上游转子改变旋转方向,减流效果出现明显差异。 展开更多
关键词 Savonius型转轮 减流 阵列单元 尾流场
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旋翼洗流对发动机喷流影响的计算分析 被引量:16
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作者 苏媛 王吉飞 +1 位作者 曹义华 陈江锋 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2001年第3期297-300,共4页
通过考察旋翼洗流对发动机喷流的影响来研究直升机发动机喷流的流动形式 .首先应用自由尾流分析技术来计算旋翼尾迹和发动机绕排流空间的洗流速度 .然后计算发动机的喷流轨迹 ,喷流截面形状和喷流物理参量 。
关键词 旋翼空气动力学 尾流 发动机 喷流干扰 直升飞机 计算
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前飞状态旋翼尾迹测量试验研究 被引量:5
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作者 袁红刚 李进学 +1 位作者 杨永东 王天虹 《实验流体力学》 EI CAS CSCD 北大核心 2010年第4期29-32,共4页
利用PIV技术,测量前飞状态旋翼尾迹的横向速度分布及桨尖涡在横向剖面里的运动轨迹,得到了前飞状态旋翼两侧的尾迹边界及桨尖涡在运动过程中的耗散特性等,研究了风速及拉力系数对前飞状态旋翼尾迹和桨尖涡运动轨迹的影响。结果表明:前... 利用PIV技术,测量前飞状态旋翼尾迹的横向速度分布及桨尖涡在横向剖面里的运动轨迹,得到了前飞状态旋翼两侧的尾迹边界及桨尖涡在运动过程中的耗散特性等,研究了风速及拉力系数对前飞状态旋翼尾迹和桨尖涡运动轨迹的影响。结果表明:前飞状态下,旋翼左右两侧尾迹的涡量值基本相当。旋翼尾迹沿径向急剧收缩,沿垂向逐渐下降,下降高度与流向距离几乎呈线性关系。风速、拉力系数的变化对桨尖涡及其运动轨迹有显著的影响。获得的测量结果为开展旋翼流动机理研究及提高CFD分析精度提供了试验依据。 展开更多
关键词 旋翼 尾迹 前飞试验 测量 PIV
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基于PIV技术的纵列式双旋翼尾迹特性实验研究 被引量:6
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作者 黄水林 林永峰 +2 位作者 黄建萍 李明 刘平安 《空气动力学学报》 EI CSCD 北大核心 2012年第3期334-339,共6页
将现有单旋翼实验台进行改装,以适合于纵列式双旋翼的实验研究。基于PIV技术,针对悬停和前飞状态下的纵列式双旋翼时的桨尖涡特性进行了测量。通过改变前后旋翼的水平和轴向间距,调整两旋翼之间的重叠区域,研究了不同气动布局纵列式双... 将现有单旋翼实验台进行改装,以适合于纵列式双旋翼的实验研究。基于PIV技术,针对悬停和前飞状态下的纵列式双旋翼时的桨尖涡特性进行了测量。通过改变前后旋翼的水平和轴向间距,调整两旋翼之间的重叠区域,研究了不同气动布局纵列式双旋翼干扰状态下的尾迹结构,并与单旋翼进行了对比。结果表明:悬停状态,随两旋翼纵向间距的增加,桨尖涡的轴向位移也逐渐增大,但桨尖涡径向位移并不是随纵向间距的改变而规律变化,在纵向间距为1.8R附近时最小;而双旋翼轴向间距的变化对桨尖涡的径向和轴向位移均有影响,但变化都不是很大。 展开更多
关键词 直升机 旋翼 纵列式 尾迹 桨尖涡 PIV
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风场风速特性的研究 被引量:8
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作者 张舜德 高文元 +1 位作者 王现青 褚金 《机械设计与制造》 北大核心 2010年第8期150-151,共2页
针对风力发电机空气动力学和结构分析的要求,建立了普通风场的数学模型。在考虑风剪和上游风力机尾流对风速影响的基础上,进行修正风速模型。并运用simulink对某一风场的风力发电机输出功率进行仿真分析。
关键词 风速模型 风剪 尾流 风力机模型 仿真
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共轴式双旋翼气动特性的固定尾迹分析 被引量:5
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作者 王平 王适存 郭才根 《南京航空航天大学学报》 EI CAS CSCD 北大核心 1997年第6期708-711,共4页
对经典的儒氏旋翼涡系模型作了一些修正,建立了悬停状态下共轴式旋翼的固定尾迹模型,对双旋翼之间的气动干扰问题开展了理论研究和实验研究,最后,将理论结果与实验结果进行了比较、分析,证明了理论方法的正确性,并获得了一些重要... 对经典的儒氏旋翼涡系模型作了一些修正,建立了悬停状态下共轴式旋翼的固定尾迹模型,对双旋翼之间的气动干扰问题开展了理论研究和实验研究,最后,将理论结果与实验结果进行了比较、分析,证明了理论方法的正确性,并获得了一些重要结论。 展开更多
关键词 直升机 旋翼空气动力学 共轴式旋翼 尾迹
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悬停旋翼的自由尾迹计算 被引量:5
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作者 徐国华 王适存 《南京航空航天大学学报》 EI CAS CSCD 北大核心 1998年第2期126-131,共6页
在随桨叶旋转的坐标系中,建立了悬停旋翼自由尾迹计算的迭代方法和模型。文中以两种不同的模型旋翼为算例,对叶尖涡的轴向和径向位置进行了计算,并与已有的试验结果进行了对比,检验了模型的可靠性。运用上述自由尾迹模型,分别研究... 在随桨叶旋转的坐标系中,建立了悬停旋翼自由尾迹计算的迭代方法和模型。文中以两种不同的模型旋翼为算例,对叶尖涡的轴向和径向位置进行了计算,并与已有的试验结果进行了对比,检验了模型的可靠性。运用上述自由尾迹模型,分别研究了不同叶尖马赫数、桨距角和桨叶片数时悬停尾迹形状的变化,表明了旋翼参数对自由尾迹形状的影响。最后,文末给出了一些结论。 展开更多
关键词 直升机 旋翼 尾流 旋翼空气动力学 涡元 自由尾迹
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旋翼尾流与地面干扰时地面涡现象的研究 被引量:4
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作者 康宁 孙茂 《力学学报》 EI CSCD 北大核心 1998年第5期615-620,共6页
用N-S方程对近地飞行时旋翼尾流与地面干扰时产生的地面涡现象进行了数值计算旋翼对流场的作用由分布在特定区域内的动量源项模拟结果表明,旋翼尾流撞到地面后的卷起和轴向流动的拉伸作用是形成地面涡的原因;地面边界层形成的... 用N-S方程对近地飞行时旋翼尾流与地面干扰时产生的地面涡现象进行了数值计算旋翼对流场的作用由分布在特定区域内的动量源项模拟结果表明,旋翼尾流撞到地面后的卷起和轴向流动的拉伸作用是形成地面涡的原因;地面边界层形成的二次分离涡向地面涡内输入(与尾流所携带的涡量)相反的涡量,而使地面涡保持平衡; 展开更多
关键词 旋翼尾流 地面涡 N-S方程 地面干扰
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一种新的尾迹-地面干扰修正方法 被引量:4
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作者 陈仁良 辛冀 李攀 《南京航空航天大学学报》 EI CAS CSCD 北大核心 2012年第5期694-699,共6页
在使用涡尾迹方法对处于地面效应状态下的旋翼进行气动计算时,会出现由于部分涡丝运动至地面下方而导致的尾迹迭代不易收敛、尾迹结构计算不够准确等问题。针对这一问题,基于空气的低速不可压理论,提出了一种新的尾迹-地面干扰修正办法... 在使用涡尾迹方法对处于地面效应状态下的旋翼进行气动计算时,会出现由于部分涡丝运动至地面下方而导致的尾迹迭代不易收敛、尾迹结构计算不够准确等问题。针对这一问题,基于空气的低速不可压理论,提出了一种新的尾迹-地面干扰修正办法。该方法与之前的方法相比,能将地面附近的涡丝修正到更准确的位置。算例表明,引入该方法的计算模型,获得的尾迹位置总体精度提高,尾迹迭代的收敛速度也有所增加。 展开更多
关键词 旋翼 自由尾迹 地面效应 干扰修正
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一种新的自由涡尾迹计算方法 被引量:6
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作者 曾洪江 胡继忠 《航空学报》 EI CAS CSCD 北大核心 2004年第6期546-550,共5页
在使用自由涡理论进行旋翼气动计算时,尾迹几何结构的确定是计算旋翼气动载荷以及空间流场计算的关键。发展了一种新的自由涡尾迹结构计算方法,该方法能快速得到收敛的尾迹结构,能比较准确地计算桨叶载荷分布。算例与实验数据的比较验... 在使用自由涡理论进行旋翼气动计算时,尾迹几何结构的确定是计算旋翼气动载荷以及空间流场计算的关键。发展了一种新的自由涡尾迹结构计算方法,该方法能快速得到收敛的尾迹结构,能比较准确地计算桨叶载荷分布。算例与实验数据的比较验证了该方法的正确性。 展开更多
关键词 直升机 自由尾迹 尾迹结构 旋翼气动载荷 尾迹收敛性
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