Computational Characterization of Unsteadiness and Turbulence in Rotor Hub Wakes

IF 1.4 4区工程技术 Q2 ENGINEERING, AEROSPACE

Journal of the American Helicopter Society Pub Date : 2022-01-01 DOI:10.4050/jahs.68.012007

Forrest Mobley, Tristan D. Wall, J. Coder

引用次数: 0

Abstract

Reynolds stresses and turbulent kinetic energy are studied in the wakes of several helicopter rotor hub geometries in forward flight. Computational fluid dynamics simulations are performed using NASA’s OVERFLOW 2.2n Reynolds-averaged Navier–Stokes solver. The simulations impose flow conditions based on previous and current experimental and numerical studies. Discrete Fourier transforms are used to examine velocity harmonics for several frequencies and compared against available experimental results. Components of the Reynolds stress tensor are computed and examined. Production and transport of the turbulent kinetic energy are examined through the rotor hub wakes at six streamwise coordinates. It was found that the scissor arms, previously found to have a significant effect on rotor hub force harmonics, also had a significant effect on the magnitudes of Reynolds stresses and turbulent kinetic energy. Integrated values of turbulent kinetic energy flux indicate that drag-reducing designs have a direct effect on turbulent kinetic energy levels in the wake.

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旋翼轮毂尾迹非定常与湍流的计算表征

研究了几种直升机旋翼轮毂前飞尾迹中的雷诺应力和湍流动能。计算流体动力学模拟使用NASA的OVERFLOW 2.2n reynolds -average Navier-Stokes解算器进行。在以往和目前的实验和数值研究的基础上，模拟施加了流动条件。离散傅里叶变换用于检查几个频率的速度谐波，并与现有的实验结果进行比较。计算并检验了雷诺应力张量的分量。通过转子轮毂尾迹在6个流向坐标处考察了湍流动能的产生和传递。研究发现，剪臂不仅对转子轮毂力谐波有显著影响，而且对雷诺数应力和湍流动能的大小也有显著影响。湍流动能通量的积分值表明，减阻设计对尾迹湍流动能水平有直接影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of the American Helicopter Society 工程技术-工程：宇航

CiteScore

4.10

自引率

33.30%

发文量

审稿时长

>12 weeks

期刊介绍： The Journal of the American Helicopter Society is a peer-reviewed technical journal published quarterly (January, April, July and October) by AHS — The Vertical Flight Society. It is the world''s only scientific journal dedicated to vertical flight technology and is available in print and online. The Journal publishes original technical papers dealing with theory and practice of vertical flight. The Journal seeks to foster the exchange of significant new ideas and information about helicopters and V/STOL aircraft. The scope of the Journal covers the full range of research, analysis, design, manufacturing, test, operations, and support. A constantly growing list of specialty areas is included within that scope. These range from the classical specialties like aerodynamic, dynamics and structures to more recent priorities such as acoustics, materials and signature reduction and to operational issues such as design criteria, safety and reliability. (Note: semi- and nontechnical articles of more general interest reporting current events or experiences should be sent to the VFS magazine