Utilising a Naturally Occurring Drag Reduction Method

利用自然发生的减阻方法

• 批准号: EP/V006614/2
• 负责人: Paul Griffiths
• 金额: $ 15.38万
• 依托单位: Aston University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV006614%2F2
• 关键词: Utilising; Naturally; Occurring; Drag; Reduction

It is now evident that the global climate is changing. In October of 2018, the United Nations (UN) Intercontinental Panel on Climate Change issued a special report on the impacts of global warming. The report notes that "rapid and far-reaching" changes will be required in order to achieve "net-zero" CO2 emissions by 2050. At present, one of the largest sources of CO2 emissions stems directly from the burning of fossil fuels for transportation purposes. Maritime transport alone emits around 940 million tonnes of CO2 annually and is responsible for around 2.5% of the total global greenhouse gas emissions. It is well understood that a major contributing factor to this worldwide fuel consumption (and, by proxy, greenhouse gas emissions) is skin-friction drag. This force is associated with the drag that all bodies experience as they move through a fluid. Whether that fluid be air, water or otherwise, skin-friction drag will always be present and energy is required to overcome its effect. This includes human energy input in competitive swimming and cycling.Given the tangible detrimental effects and related societal consequences of global warming, research into techniques that act to reduce skin-friction drag in cars, aeroplanes, ships has intensified in recent decades. One source of inspiration for these drag reduction techniques has come from the study of fliers and swimmers. For the purposes of survival, birds and fish have been adapting for many millennia. It is these adaptations that have most interested scientists. More specifically, the research community has focused on the idea that evolution has ensured that these species move incredibility efficiently through their fluid-centred habitats. A relatively recent example that has garnered a great deal of attention from fluid mechanists is the reduction of skin-friction drag via the introduction of shark-skin-like rough surfaces when attached to flexible membranes, in particular. A boundary-layer flow is the flow of a thin layer of fluid above or below a bounding surface. These types of flow are pervasive and can be directly affected by skin-friction drag. This project will investigate, theoretically, the idea that boundary-layer flows can be actively controlled via biologically-inspired drag reduction techniques observed operating in the natural world. The goal of the investigation will be to develop mathematical techniques that can be used to model the control of such flows with a specific focus on the ability to delay the onset of turbulent transition. Turbulent flows play a significant role in reducing fuel efficiency and, in the case of fossil-fuel burning engines, have an associated impact in increasing harmful CO2 emissions. In relation to the increasing number of electrical vehicles the road and the associated UK Government's advancement of the cessation of diesel and petrol vehicle production, improved drag reduction techniques would produce improved range performance, that at present to the public is a perceived reason for not readily adopting the technology. The results that stem from this study will provide new insights into active flow control methods which can then be utilised to reduce the effects of drag and improve global fuel consumption with resultant economic benefits.

现在很明显，全球气候正在发生变化。 2018年10月，联合国洲际气候变化专门委员会发布了关于全球变暖影响的特别报告。报告指出，为了到 2050 年实现二氧化碳“净零”排放，需要进行“迅速而深远”的改变。目前，二氧化碳排放的最大来源之一直接来自交通运输化石燃料的燃烧目的。仅海上运输每年就排放约 9.4 亿吨二氧化碳，约占全球温室气体排放总量的 2.5%。众所周知，造成全球燃料消耗（以及温室气体排放）的一个主要因素是表面摩擦阻力。这种力与所有物体在流体中移动时所受到的阻力有关。无论流体是空气、水还是其他流体，表面摩擦阻力始终存在，并且需要能量来克服其影响。这包括竞技游泳和自行车运动中的人体能量输入。考虑到全球变暖的明显有害影响和相关社会后果，近几十年来，对减少汽车、飞机和船舶表面摩擦阻力的技术的研究不断加强。这些减阻技术的灵感来源之一来自对飞行者和游泳者的研究。为了生存，鸟类和鱼类已经适应了数千年。科学家们最感兴趣的正是这些适应。更具体地说，研究界关注的观点是，进化确保了这些物种在以液体为中心的栖息地中有效地移动。最近引起流体机械师广泛关注的一个例子是，特别是在连接到柔性膜时，通过引入鲨鱼皮状的粗糙表面来减少皮肤摩擦阻力。边界层流是边界表面上方或下方的薄层流体的流动。这些类型的流动很普遍，并且可能直接受到表面摩擦阻力的影响。该项目将从理论上研究边界层流动可以通过在自然界中观察到的受生物学启发的减阻技术来主动控制的想法。研究的目标是开发可用于对此类流动的控制进行建模的数学技术，特别关注延迟湍流转变开始的能力。湍流在降低燃油效率方面发挥着重要作用，并且对于化石燃料燃烧发动机而言，还会增加有害二氧化碳排放量。随着道路上电动汽车数量的不断增加以及相关英国政府推动停止柴油和汽油汽车生产，改进的减阻技术将提高续航里程性能，但目前公众认为这一点并不容易实现。采用该技术。这项研究的结果将为主动流量控制方法提供新的见解，然后可用于减少阻力的影响并改善全球燃料消耗，从而产生经济效益。

项目成果

Revisiting boundary layer flows of viscoelastic fluids

重新审视粘弹性流体的边界层流动

• DOI: http://dx.10.48550/arxiv.2302.08013
• 发表时间: 2023
• 作者: Escott L

Revisiting boundary layer flows of viscoelastic fluids

重新审视粘弹性流体的边界层流动

• DOI: http://dx.10.1016/j.jnnfm.2022.104976
• 发表时间: 2023
• 期刊: Journal of Non-Newtonian Fluid Mechanics
• 影响因子: 3.1
• 作者: Escott L