Experimental studies and control of wall-bounded and separated shear layers using active flow control

使用主动流动控制对壁限和分离剪切层进行实验研究和控制

• 批准号: RGPIN-2019-07108
• 负责人: Lavoie, Philippe
• 金额: $ 3.35万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716103
• 关键词: Experimental; studies; control; wall; bounded

The aerospace sector plays an important role in the Canadian economy. In 2017, it accounted for approximately $25 billion in GDP and nearly 190,000 high-paying jobs. In the specific case of aviation, climate change and noise pollution represents some of its most significant challenges and are risks to the industry. In order for the Canadian aerospace industry to remain globally competitive, step changes in technology are required. Active flow control is one of the technologies considered to help meet the stringent environmental targets set on the aerospace industry by the International Air Transport Association (IATA). The proposed research will development and implementation novel active flow control strategies with an emphasis on flow fields that are relevant to the Canadian aerospace industry. Specific active flow control objectives to be investigated are: (i) reduction of skin-friction drag due to turbulent boundary layers, and (ii) wake control to decrease the pressure drag and noise emissions from blunt trailing edge airfoils. (1) Previous studies demonstrated ~30% reduction in skin friction in turbulent boundary layers through active control of the near-wall turbulence. However, recent works suggests that these benefits would not scale to flight Reynolds number. A new approach of controlling the turbulent boundary layer through the manipulation of the large coherent structures present in the log-region will be considered with this proposal. These structures are known to become more dominant at large Reynolds number and can offer a more practical pathway to implementation given their larger sizes compared to the near-wall structures. (2) Airfoils with blunt trailing edges are common in the aerospace industry since they can provide superior lift to drag ratios and improved structural integrity. However, the wake associated with these causes higher levels of pressure drag, fluctuating aerodynamic forces and noise. Preliminary studies by the applicant with a blunt trailing edge streamlined body demonstrated an effective active flow control methodology that produced a reduction in pressure drag of approximately 30% and over 90% less unsteadiness in the wake. It is proposed to take this methodology closer to industrial application by extending its use to blunt trailing edge airfoils. This will lead to significant better performance for these airfoils. The practical ramifications of this research are significant and wide ranging. They include the reduction of drag, fuel consumption and noise emissions in a variety of commercially relevant fluid systems. These benefits will lead to a reduction in the aerospace industry's dependence on fossil fuels and a decrease in greenhouse gas emissions. The research is also transformative since it addresses open questions that, in the long term, should lead to a paradigm shift with respect to the design practices for energy efficiency of, and pollution reduction from, fluidic systems.

航空航天部门在加拿大经济中起着重要作用。 2017年，它占GDP的约250亿美元和近190,000个高薪工作。在航空的具体情况下，气候变化和噪声污染代表了其最重要的挑战，是该行业的风险。为了使加拿大航空航天行业保持全球竞争，需要进行技术变化。主动流量控制是被认为有助于实现国际航空运输协会（IATA）设定的严格环境目标的技术之一。 拟议的研究将开发和实施新型的主动流控制策略，重点是与加拿大航空航天行业相关的流场。要研究的特定主动流控制目标是：（i）减少由于湍流边界层而导致的皮肤摩擦阻力，以及（ii）尾流控制以减少钝的尾随边缘机翼的压力阻力和噪声发射。 （1）先前的研究表明，通过积极控制近壁湍流，湍流边界层皮肤摩擦的降低约为30％。但是，最近的作品表明，这些好处不会扩展到雷诺的飞行数字。通过该建议将考虑一种通过操纵对数区域中存在的大相干结构来控制湍流边界层的新方法。已知这些结构在较大的雷诺数字上变得更有主导，并且鉴于与近壁结构相比，它们的尺寸较大，可以为实施提供更实际的途径。 （2）在航空航天行业中，具有钝器尾随的边缘的机翼很常见，因为它们可以提供较高的升力与阻力比和改善的结构完整性。但是，与这些相关的尾流会导致更高的压力阻力，使空气动力和噪声波动。申请人对钝的尾随边缘体的初步研究表明，一种有效的主动流控制方法，导致压力阻力降低约30％，而在尾声中的不稳定降低了90％以上。建议通过扩展其对钝的边缘机翼的钝化来使这种方法更接近工业应用。这将为这些机翼带来明显的更好的性能。 这项研究的实际影响是重大且广泛的。其中包括减少多种商业相关流体系统中阻力，燃油消耗和噪声排放。这些好处将导致航空航天行业对化石燃料的依赖减少，并减少温室气体排放。这项研究也具有变革性，因为从长远来看，这应该导致有关液体系统的能源效率和污染降低的设计实践的范式转变。