Experimental and Computational Turbulence in Engineering and Biological Flows

工程和生物流中的实验和计算湍流

• 批准号: RGPIN-2015-06575
• 负责人: Pollard, Andrew
• 金额: $ 2.48万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=662392
• 关键词: Experimental; Computational; Turbulence; Engineering; Biological

My research programme focuses on the discovery of the underlying principles and the flow physics that govern the spatial and temporal evolution of the structure of turbulence in both free turbulent flows (e.g. jets) and wall-bounded flows (e.g. inside the human airway).****The objectives of the research, each of which will employ both computer simulation and physical experiments, are to explore the near nozzle region of round turbulent jets to discover the extent and nature of the turbulence encountered therein and to discover how the pressure drop and the three dimensional velocity distributions in obstructed human airways are improved because of surgical intervention. ****Jets that are free of any confinement are common and a critically important fundamental flow. Flow in the nozzle area, where the jet starts, and well away from the start of the jet, called the far field, has been extensively studied. However, a region that bridges the near-nozzle area to the far field, which is rich in flow physics, is poorly understood and yet plays the role to transport initial inlet conditions through to fully developed turbulence in the far field. My students and I will apply direct numerical simulation (DNS) and use our unique flying hot wire facility to critically assess the anisotropic and non-homogeneous regions of a jet off its centreline. We will introduce passive control rings in the near nozzle region to alter the initial conditions thereby enhancing mixing and potentially reducing noise, which is of interest to Bombardier Aerospace.****Normal lung function is associated with delivery of the same amount of air to each lung. Obstructed airflow in the human airway gives rise to breathing difficulties and asymmetry in air delivery to the lungs. Obstructive sleep apnea (OSA), often associated with tonsil/adenoid blockage, may require surgery to rectify. Normal human airways are geometrically complex in shape and produce complicated flow patterns throughout the airway, particularly at and beyond the epiglottis and into the trachea to produce what is called the laryngeal jet, which contain flow features seen in free jets. The geometries in patients with OSA are exceptionally more complex and can produce highly asymmetric flow in the trachea that can lead to uneven distribution of flow to the lungs. We will use DNS and optical measurements to explore the flow inside pre- and post-operative geometries. Parents face growing concern as children are increasingly experiencing a range of breathing-related health issues and pediatric airway surgeries are being performed more often today.  Clinicians need to be more informed about the fluid dynamic consequences enabled by their surgeries, which this research will enable.****During this DG period, 14 HQP will be trained in advanced research techniques in fluid dynamics and will develop professional and communication skills to prepare them for careers in academe and industry.**

我的研究计划侧重于发现基本原理和流动物理学，这些原理和流动物理学支配着自由湍流（例如射流）和壁边界流动（例如人体气道内）中湍流结构的时空演变。研究的目的，其中每一个将采用计算机模拟和物理实验，是探索近喷嘴区域的圆形湍流射流，发现的程度和性质的湍流遇到其中，并发现如何在阻塞的人体气道的压降和三维速度分布，因为手术干预改善。* 没有任何限制的射流是常见的，并且是至关重要的基本流。在喷嘴区域，射流开始的地方，以及远离射流开始的地方，称为远场，已经被广泛研究。然而，一个区域的桥梁，近喷嘴区的远场，这是丰富的流动物理，知之甚少，但发挥的作用，运输初始入口条件，通过充分发展的湍流在远场。我和我的学生将应用直接数值模拟（DNS），并使用我们独特的飞行热线设施来严格评估射流偏离其中心线的各向异性和非均匀区域。我们将在近喷嘴区域引入被动控制环，以改变初始条件，从而增强混合并可能降低噪音，这是庞巴迪宇航公司感兴趣的。*正常的肺功能与向每个肺输送相同量的空气有关。人体气道中的阻塞气流引起呼吸困难和向肺部输送空气的不对称性。阻塞性睡眠呼吸暂停（OSA），通常与扁桃体/腺样体阻塞有关，可能需要手术来纠正。正常的人体气道在几何形状上是复杂的，并且在整个气道中产生复杂的流动模式，特别是在会厌处和会厌之外并进入气管以产生所谓的喉射流，其包含在自由射流中看到的流动特征。OSA患者的几何形状异常复杂，并且可以在气管中产生高度不对称的流动，这可能导致流向肺部的流动分布不均匀。我们将使用DNS和光学测量来探索术前和术后几何形状内的流动。随着儿童越来越多地遇到一系列与呼吸相关的健康问题，以及当今儿科气道手术越来越频繁，家长们面临着越来越多的担忧。临床医生需要更多地了解手术所带来的流体动力学后果，这项研究将使之成为可能。*在此期间，14名HQP将接受流体动力学先进研究技术的培训，并将发展专业和沟通技能，为他们在工业和工业中的职业生涯做好准备。