Fundamentals and applications of arrangements of pulsed fluid jets

单个脉冲流体射流通常与水生动物的运动有关，如鱿鱼、章鱼、鹦鹉螺、水母甚至扇贝。在工业上，它们被应用于水射流加工、牙科和电子元件的冷却。因此，对单个脉冲射流的流体动力学及其应用的发展进行了大量的研究就不足为奇了。然而，对于两个或多个脉冲射流排列的流体动力学，我们所知甚少。在水生动物（例如，海带、虹吸管）中也观察到脉冲射流的排列，并有许多有前途的应用，可以对加拿大的健康和创新产生重大影响。例如，我们的膀胱由两个脉冲输尿管喷射间歇填充。众所周知，在患有肾结石等泌尿系统疾病的情况下，这些尿液的行为会发生变化，每10个加拿大人中就有1个患有肾结石。因此，更好地了解脉冲射流对的流体动力学可以导致膀胱超声流动模式与泌尿系统健康之间的联系。在工程上，脉冲射流可以作为自主水上机器人和车辆的节能运动手段。因此，该研究项目将开拓脉冲射流布置的流体动力学知识，并开发新的先进应用和技术，以造福加拿大。这个项目被安排成三个主要方向或轴。在研究轴1中，我们将在自由和密闭环境中对两个单脉冲流体射流进行参数化、三维、时间分辨的数值和实验研究。这项研究将显著推进脉冲射流对流体动力学的知识，这将为某些生理和病理的尿流和心流提供急需的见解。从该轴产生的知识还有望促进在诸如水上车辆运动、减缓流动分离和剪切敏感物质的工业/批量混合等应用中的创新。在接下来的研究中，我们将研究和开发脉冲射流在后两种应用中的使用。在研究轴2中，我们将研究脉冲射流阵列在平板（实验）和翼型（数值）上减轻流动分离的能力。这项研究有望带来一种新的策略和技术，以减轻飞机机翼在动态迎角范围内的流动分离，从而提高燃油经济性。在研究轴3中，我们将通过数值模拟研究和模拟在受限圆形环境下的最佳低剪切混合方案，并开发一种脉冲射流控制的间歇混合装置。由此产生的技术有望在减少剪切敏感物质（例如某些食品）混合的能量消耗的情况下显著改善混合时间。

Individual pulsed fluid jets are often associated with the locomotion of aquatic animals such as squid, octopuses, nautiluses, jellyfish and even scallops. In industry, they find applications in water jet machining, dentistry and the cooling of electronic components. It therefore comes as no surprise that significant research has been devoted to the fluid dynamics of the individual pulsed jet and the development of its applications. Very little, however, is known about the fluid dynamics of arrangements of two or more pulsed jets. Arrangements of pulsed jets are also observed in aquatic animals (e.g., salps, siphonophores) and have many promising applications that can have a significant impact on health and innovation in Canada. For example, our bladders fill intermittently from two pulsed ureteric jets. The behaviour of these jets is known to change in the presence of adverse urinary conditions such as kidney stones, which affects 1 in 10 Canadians. A better understanding of the fluid dynamics of pairs of pulsed jets can therefore lead to a link between bladder ultrasound flow patterns and the health of the urinary system. In engineering, pulsed jets can be used as an energy-efficient means of locomotion for autonomous aquatic robots and vehicles. This research program will therefore pioneer knowledge of the fluid dynamics of pulsed jet arrangements and develop new advanced applications and technologies to Canada's benefit. This program is arranged into three principal directions or axes. In Research Axis 1, we will conduct parametric, three-dimensional, time-resolved numerical and experimental studies of two single-pulsed fluid jets in free and confined environments. This research will significantly advance knowledge of the fluid dynamics of pairs of pulsed jets, which will provide much needed insight for certain physiological and pathological urinary and cardiac flows. The knowledge generated from this axis is also expected to bolster innovation in such applications as aquatic vehicle locomotion, mitigation of flow separation and industrial/batch mixing of shear-sensitive substances. In the following research axes, we will research and develop the use of pulsed jets for the latter two applications. In Research Axis 2, we will investigate the ability of an array of pulsed jets to mitigate flow separation on a flat plate (experimentally) and over airfoils (numerically). This research is expected to lead to a novel strategy and technology to mitigate flow separation over aircraft wings for a dynamic range of angles of attack, thereby improving fuel economy. In Research Axis 3, we will investigate and model optimal, low shear mixing protocols in a confined circular environment through numerical simulations and develop a pulsed-jet-controlled batch mixing device. The resulting technology is expected to markedly improve mixing times at a reduced energy expense for the mixing of shear-sensitive substances (e.g., certain food products).