Roll stall and the vortex-induced aerodynamic of low-aspect-ratio fliers

低展弦比飞行器的滚转失速和涡流引起的空气动力学

基本信息

批准号：
1805776
负责人：
Kamran Mohseni
金额：
$ 30万
依托单位：
University of Florida
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2021-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1805776&HistoricalAwards=false
关键词：
Roll stall vortex induced aerodynamic

项目摘要

The design and development of highly-maneuverable aircraft has been a long-standing engineering challenge. This challenge presents itself in almost all flight regimes, from supersonic fighter jets down to low-speed, smaller-scale unmanned aircraft. Despite the very different operating conditions, there is at least one common feature among aircraft designs aiming to provide very agile, yet stable, flight. Namely, the planforms (the shape and layout of an airplane's wing) of such aircraft are of low aspect ratio. Recent studies suggest that the aerodynamic and gust-response of such low aspect ratio fliers are significantly different than larger flyers and not well understood. This issue constitutes a critical gap in aerial vehicle development, and this research project addresses a critical gap in the development of reliable and fully controllable aerial drones. The researchers will also enhance course curricula with results from this research, and a course on unsteady low Reynolds number aerodynamics will be developed. A summer program is proposed that will enable local high school students to learn aerodynamics and flight concepts and to participate in a design/build/operate competition integrating fluid dynamics, aerodynamics, and aircraft design. This research project takes a fresh look into new features of steady and unsteady aerodynamics of low aspect ratio wings. Recent discoveries of complex aerodynamic flow-structure interactions have been attributed to an inherent coupling of lateral and longitude loadings and these are unique to low aspect ratio flyers. These phenomena are, in turn, related to the vortex-dominated flow generated by such wings. The proposed work is divided into three main research thrusts. (i) The prediction of flow separation, (ii) The connection between unsteady vortex generation of low-aspect-ratio surfaces and the instantaneous loadings, and (iii) Understanding of how key changes to the vortex topology over a wing in cross-flow modify the asymmetric wing loading. Flow field measurements using digital particle image velocimetry and direct force/moment measurements are correlated with the vortex structures in the flow. Some theoretical modeling will also complement the experimental effort. This knowledge may motivate unique flow control or wing morphing strategies during flight in gusty environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

高度机动飞机的设计和开发一直是一项长期存在的工程挑战。从超音速战斗机到低速、小型无人机，几乎所有飞行模式都面临着这一挑战。尽管操作条件截然不同，但飞机设计至少有一个共同特征，旨在提供非常敏捷而稳定的飞行。即，这种飞机的平面形状（飞机机翼的形状和布局）具有低展弦比。最近的研究表明，这种低展弦比飞行器的空气动力学和阵风响应与较大的飞行器有显着不同，并且尚不清楚。这个问题构成了飞行器开发中的一个关键差距，而该研究项目解决了开发可靠且完全可控的无人机中的一个关键差距。研究人员还将利用这项研究的结果来加强课程课程，并将开发一门关于非定常低雷诺数空气动力学的课程。建议开展一个暑期项目，让当地高中生学习空气动力学和飞行概念，并参加集流体动力学、空气动力学和飞机设计于一体的设计/建造/操作竞赛。该研究项目重新审视低展弦比机翼的稳态和非稳态空气动力学的新特征。最近发现的复杂空气动力学流动-结构相互作用归因于横向和纵向载荷的固有耦合，并且这些是低展弦比飞行器所独有的。这些现象又与此类机翼产生的涡流主导的流动有关。拟议的工作分为三个主要研究方向。（i）流动分离的预测，（ii）低展弦比表面的不稳定涡流生成与瞬时载荷之间的联系，以及（iii）了解横流中机翼上涡流拓扑的关键变化修改不对称机翼载荷。使用数字粒子图像测速法和直接力/力矩测量的流场测量与流动中的涡流结构相关。一些理论模型也将补充实验工作。这些知识可能会在阵风环境中的飞行过程中激发独特的流量控制或机翼变形策略。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。