Towards drag reduction strategies for high Reynolds number wall-turbulence

针对高雷诺数壁湍流的减阻策略

• 批准号: EP/L006383/1
• 负责人: Bharathram Ganapathisubramani
• 金额: $ 65.37万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL006383%2F1
• 关键词: Towards; drag; reduction; strategies; Reynolds

Reduction of skin-friction drag in various applications in the transportation and energy generation sectors would translate directly to reductions in fuel consumption and emissions. Consequently, there is flurry of activity around the world aimed at developing control strategies to reduce skin-friction drag. Almost all of these strategies focus on controlling the near-wall ``streaks" by using a range of exciting control methodologies. However, all these techniques are developed in low Reynolds number computations and experiments and their applicability in high Reynolds number flows is an open question. Moreover, recent studies have unravelled new physics at higher Reynolds numbers, i.e. the existence of very large scale motions (VLSM). These VLSMs make a significant contribution to kinetic energy production in high Reynolds number flows and influence the near-wall cycle thereby making a significant contribution to skin-friction drag. Therefore, effective control of VLSMs could directly lead to a decrease in skin-friction drag. In the current project, a novel physics-based control strategy for high Reynolds number wall-turbulence is proposed in which the goal is to control the impact of VLSMs. In the first part of the project, a detailed exploration of the physical mechanism of VLSMs and its relationship to skin-friction drag will be carried out. In the second part, an active control strategy will be developed to manipulate these VLSMs with the ultimate goal of reducing skin-friction drag.

在运输和能源生产部门的各种应用中，减少表面摩擦阻力将直接转化为燃料消耗和排放的减少。因此，世界各地出现了一系列旨在开发控制策略以减少表面摩擦阻力的活动。几乎所有这些战略都侧重于通过使用一系列令人兴奋的控制方法来控制近墙“条纹”。然而，所有这些技术都是在低雷诺数计算和实验中发展起来的，它们在高雷诺数流动中的适用性是一个悬而未决的问题。此外，最近的研究揭示了高雷诺数下的新物理，即超大尺度运动(VLSM)的存在。这些VLSM在高雷诺数流动中对动能的产生有重要贡献，并影响近壁循环，因此对壁面摩擦阻力有很大贡献。因此，对VLSM的有效控制可以直接导致壁面摩擦阻力的减小。在本项目中，提出了一种新的基于物理的高雷诺数壁面湍流控制策略，其目标是控制VLSM的影响。在项目的第一部分，将对VLSM的物理机制及其与表面摩擦阻力的关系进行详细的探索。在第二部分中，将开发一种主动控制策略来操纵这些VLSM，最终目标是减少壁面摩擦阻力。

项目成果

Law of the wall for small-scale streamwise turbulence intensity in high-Reynolds-number turbulent boundary layers

高雷诺数湍流边界层小尺度流向湍流强度的壁面定律

• DOI: 10.1103/physrevfluids.3.104607
• 发表时间: 2018
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: Ganapathisubramani B

Entrainment effects in periodic forcing of the flow over a backward-facing step

• DOI: 10.1103/physrevfluids.2.074605
• 发表时间: 2017-02
• 作者: T. Berk;T. Medjnoun;B. Ganapathisubramani

Spatial characteristics of a zero-pressure-gradient turbulent boundary layer in the presence of free-stream turbulence

自由流湍流存在下零压力梯度湍流边界层的空间特征

• DOI: 10.1103/physrevfluids.4.084601
• 发表时间: 2019
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: Dogan E

Structure of high and low shear-stress events in a turbulent boundary layer

• DOI: 10.1103/physrevfluids.3.014609
• 发表时间: 2018-01-19
• 期刊: PHYSICAL REVIEW FLUIDS
• 影响因子: 2.7
• 作者: Gomit, G.;de Kat, R.;Ganapathisubramani, B.
• 通讯作者: Ganapathisubramani, B.

Vectoring of parallel synthetic jets: a parametric study

• DOI: 10.1017/jfm.2016.559
• 发表时间: 2016-09
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: T. Berk;G. Gomit;B. Ganapathisubramani