Experimental and computational investigation of the Knoller-Betz effect
Experimental and computational investigation of the Knoller-Betz effect
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DOI：
10.2514/2.505
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发表时间：
1998-07-01
期刊：
影响因子：
2.5
通讯作者：
Platzer, MF
中科院分区：
文献类型：
--
作者：
Jones, KD;Dohring, CM;Platzer, MF
本文通过实验和数值模拟研究了正弦倾伏翼型产生推力的能力，即Knoller-Betz或Katzmayr效应。水洞实验进行提供流动显示和激光多普勒测速数据的非定常尾迹形成的俯冲翼。涡结构和时间平均的速度分布在唤醒的数值计算从以前开发的无粘，非定常面板代码，利用非线性唤醒模型进行比较。定性和定量的比较是优秀的在一个广泛的范围内的减少频率和Strouhal数，表明推力指示尾流结构的形成和演变主要是无粘现象。结果在斯特劳哈尔数大于约1.0（基于暴跌幅度）表明非对称，偏转尾流模式，其中产生的平均推力和平均升力。这些高度非线性的尾流形成可重复地产生，实验和数值。
The ability of a sinusoidally plunging airfoil to produce thrust, known as the Knoller-Betz or Katzmayr effect, is investigated experimentally and numerically. Water-tunnel experiments are performed providing flow visualization and laser Doppler velocimetry data of the unsteady wakes formed by the plunging foils. Vortical structures and time-averaged velocity profiles in the wake are compared with numerical computations from a previously developed inviscid, unsteady panel code that utilizes a nonlinear wake model. Qualitative and quantitative comparisons are excellent over a broad range of reduced frequencies and Strouhal numbers, indicating that the formation and evolution of the thrust-indicative wake structures are primarily inviscid phenomena. Results at Strouhal numbers greater than about 1.0 (based on plunge amplitude) demonstrate nonsymmetric, deflected wake patterns, where both an average thrust and an average lift are produced. These highly nonlinear wake formations are generated reproducibly, both experimentally and numerically.