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.

航空航天业在加拿大经济中发挥着重要作用。 2017年，它的GDP约为250亿美元，创造了近19万个高薪工作岗位。就航空业的具体情况而言，气候变化和噪音污染是航空业面临的一些最重大的挑战，也是该行业面临的风险。为了使加拿大航空航天业保持全球竞争力，需要进行技术上的重大变革。主动流量控制是被认为有助于满足国际航空运输协会 (IATA) 为航空航天业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颖的主动流量控制策略，重点是与加拿大航空航天工业相关的流场。要研究的具体主动流动控制目标是：（i）减少由于湍流边界层引起的表面摩擦阻力，以及（ii）尾流控制以减少钝后缘翼型的压力阻力和噪声排放。 (1) 先前的研究表明，通过主动控制近壁湍流，湍流边界层的表面摩擦力可减少约 30%。然而，最近的研究表明，这些好处不会扩展到飞行雷诺数。该提案将考虑通过操纵对数区域中存在的大型相干结构来控制湍流边界层的新方法。众所周知，这些结构在大雷诺数下变得更加占主导地位，并且由于与近壁结构相比它们的尺寸更大，因此可以提供更实用的实施途径。 (2) 具有钝后缘的翼型在航空航天工业中很常见，因为它们可以提供优异的升阻比并提高结构完整性。然而，与这些相关的尾流会导致更高水平的压力阻力、波动的空气动力和噪音。申请人对钝后缘流线型机身进行的初步研究证明了一种有效的主动流量控制方法，可将压力阻力减少约 30%，并减少尾流不稳定性超过 90%。建议通过将其用途扩展到钝化后缘翼型来使该方法更接近工业应用。这将使这些机翼的性能显着提高。 这项研究的实际影响是重大且广泛的。它们包括减少各种商业相关流体系统的阻力、燃料消耗和噪音排放。这些好处将减少航空航天业对化石燃料的依赖并减少温室气体排放。这项研究还具有变革性，因为它解决了一些悬而未决的问题，从长远来看，这些问题应该会导致流体系统的能源效率和减少污染的设计实践发生范式转变。