Lavrinenko Akim, Fabregat Alexandre, Pallares Jordi
Departament d'Enginyeria Mecánica, Universitat Rovira i Virgili, Spain, Av. Països Catalans, Tarragona 26, 43007 Spain.
Acta Mech Sin. 2022;38(8):721489. doi: 10.1007/s10409-022-09032-x. Epub 2022 Apr 25.
In this work we compare the DNS results (Fabregat et al. 2021, Fabregat et al. 2021) for a mild cough already reported in the literarure with those obtained with a compressible URANS equations with a turbulence model. In both cases, the dispersed phase has been modelled as spherical Lagrangian particles using the one-way coupling assumption. Overall, the URANS model is capable of reproducing the observed tendency of light particles under 64 µm in diameter to rise due to the action of the drag exerted by the buoyant puff generated by the cough. Both DNS and URANS found that particles above 64 µm will tend to describe parabolic trajectories under the action of gravitational forces. Grid independence analysis allows to qualify the impact of increasing mesh resolution on the particle cloud statistics as flow evolves. Results suggest that the model overpredicts the horizontal displacement of the particles smaller than 64 µm while the opposite occurs for the particles larger than 64 µm.
在这项工作中，我们将文献中已报道的轻度咳嗽的直接数值模拟（DNS）结果（法夫雷加特等人，2021年；法夫雷加特等人，2021年）与采用可压缩URANS方程及湍流模型获得的结果进行比较。在这两种情况下，均采用单向耦合假设，将离散相建模为球形拉格朗日粒子。总体而言，URANS模型能够再现直径小于64微米的轻质颗粒因咳嗽产生的浮力 puff 所施加的阻力作用而上升的观测趋势。DNS和URANS均发现，直径大于64微米的颗粒在重力作用下将倾向于描绘抛物线轨迹。网格独立性分析能够确定随着流动演化，网格分辨率增加对颗粒云统计的影响。结果表明，该模型高估了直径小于64微米的颗粒的水平位移，而对于直径大于64微米的颗粒则出现相反情况。
