Role of pulsatility on particle dispersion in expiratory flows.
Role of pulsatility on particle dispersion in expiratory flows.
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DOI：
10.1063/5.0048746
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发表时间：
2021-04
期刊：
影响因子：
--
通讯作者：
Capecelatro J
中科院分区：
文献类型：
--
作者：
Monroe K;Yao Y;Lattanzi A;Raghav V;Capecelatro J
呼气事件，如咳嗽，通常是脉动性的，并导致输送呼吸道颗粒的涡旋流结构。本文采用直接数值模拟（DNS）方法，结合微米级液滴的拉格朗日粒子跟踪，研究了二次和三次喷射对粒子扩散和穿透的影响。在射流口处提供了由湍流管道流动的DNS得到的充分发展的湍流。孔口处的体积流量根据阻尼正弦波及时调制，从而允许控制脉冲的数量、持续时间和峰值幅度。热力学效应，如蒸发和浮力，被忽略，以孤立的作用脉动粒子分散。对单脉冲、双脉冲和三脉冲射流的涡结构进行了分析。然后将粒子云的演化与现有的单脉冲模型进行比较。粒子的扩散和穿透整个云被发现被增加的脉动所阻碍。然而，由于下游涡结构的加速作用，二次或三次喷射产生的粒子的穿透能力增强。
Expiratory events, such as coughs, are often pulsatile in nature and result in vortical flow structures that transport respiratory particles. In this work, direct numerical simulation (DNS) of turbulent pulsatile jets, coupled with Lagrangian particle tracking of micron-sized droplets, is performed to investigate the role of secondary and tertiary expulsions on particle dispersion and penetration. Fully developed turbulence obtained from DNS of a turbulent pipe flow is provided at the jet orifice. The volumetric flow rate at the orifice is modulated in time according to a damped sine wave, thereby allowing for control of the number of pulses, duration, and peak amplitude. Thermodynamic effects, such as evaporation and buoyancy, are neglected in order to isolate the role of pulsatility on particle dispersion. The resulting vortex structures are analyzed for single-, two-, and three-pulse jets. The evolution of the particle cloud is then compared to existing single-pulse models. Particle dispersion and penetration of the entire cloud are found to be hindered by increased pulsatility. However, the penetration of particles emanating from a secondary or tertiary expulsion is enhanced due to acceleration downstream by vortex structures.
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影响因子：
4.6
作者：
Boersma, BJ;Brethouwer, G;Nieuwstadt, FTM
通讯作者：
Nieuwstadt, FTM
DOI：
10.1063/5.0042086
发表时间：
2021-03-01
期刊：
Physics of fluids (Woodbury, N.Y. : 1994)
影响因子：
--
作者：
Fabregat A;Gisbert F;Vernet A;Dutta S;Mittal K;Pallarès J
通讯作者：
Pallarès J
影响因子：
3.7
作者：
Bourouiba, Lydia;Dehandschoewercker, Eline;Bush, John W. M.
通讯作者：
Bush, John W. M.
影响因子：
3.7
作者：
Aliseda, A;Cartellier, A;Lasheras, JC
通讯作者：
Lasheras, JC
影响因子：
4.1
作者：
Desjardins, Olivier;Blanquart, Guillaume;Pitsch, Heinz
通讯作者：
Pitsch, Heinz