Hetherington R, Toufique Hasan A B M, Khan A, Roy D, Salehin M, Wadud Z
School of Civil Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh.
Phys Fluids (1994). 2021 Nov;33(11):113319. doi: 10.1063/5.0069454. Epub 2021 Nov 17.
A dominant mode of transmission for the respiratory disease COVID-19 is via airborne virus-carrying aerosols. As national lockdowns are lifted and people begin to travel once again, an assessment of the risk associated with different forms of public transportation is required. This paper assesses the risk of transmission in the context of a ride-sharing motorbike taxi-a popular choice of paratransit in South and South-East Asia and Sub-Saharan Africa. Fluid dynamics plays a significant role in understanding the fate of droplets ejected from a susceptible individual during a respiratory event, such as coughing. Numerical simulations are employed here using an Eulerian-Lagrangian approach for particles and the Reynolds-averaged Navier-Stokes method for the background air flow. The driver is assumed to be exhaling virus laden droplets, which are transported toward the passenger by the background flow. A single cough is simulated for particle sizes 1, 10, , with motorbike speeds . It has been shown that small and large particles pose different types of risk. Depending on the motorbike speed, large particles may deposit onto the passenger, while smaller particles travel between the riders and may be inhaled by the passenger. To reduce risk of transmission to the passenger, a shield is placed between the riders. The shield not only acts as a barrier to block particles, but also alters the flow field around the riders, pushing particles away from the passenger. The findings of this paper therefore support the addition of a shield potentially making the journey safer.
呼吸道疾病新冠病毒肺炎（COVID-19）的一种主要传播方式是通过携带病毒的空气传播气溶胶。随着各国解除封锁，人们再次开始出行，需要评估不同形式公共交通所带来的风险。本文评估了共享摩托车出租车这种在南亚、东南亚和撒哈拉以南非洲地区广受欢迎的辅助公共交通方式的传播风险。流体动力学在理解诸如咳嗽等呼吸事件中易感个体喷出的飞沫命运方面起着重要作用。本文采用欧拉-拉格朗日方法处理颗粒，雷诺平均纳维-斯托克斯方法处理背景气流进行数值模拟。假设司机呼出携带病毒的飞沫，这些飞沫被背景气流带向乘客。针对粒径为1、10等，摩托车速度为等情况模拟了单次咳嗽。结果表明，大小颗粒带来不同类型的风险。取决于摩托车速度，大颗粒可能沉积在乘客身上，而较小颗粒在乘客之间传播并可能被乘客吸入。为降低传给乘客的风险，在乘客之间设置了一个防护装置。该防护装置不仅作为阻挡颗粒的屏障，还改变了乘客周围的流场，将颗粒从乘客身边推开。因此，本文的研究结果支持增加防护装置，这可能使行程更安全。
