## 3 Results and Discussion
### Flow Fields and Droplet Dispersion
The presence of thermal plumes exacerbates the turbulence level in the human body's microenvironment, enhancing the mixing of droplets with other airflows during their ascent, thereby expanding the distribution range of droplets in space. Additionally, the suspension duration and propagation distance of droplets in the air are constrained by evaporation and settling rates, while subtle changes in temperature and humidity in the human microenvironment have a significant impact on these rates. Therefore, to reduce the risk of personnel contracting respiratory infectious diseases, it is necessary to start by changing the direction of airflow between people. Exploring the form of hanging curtains and their height to quantitatively assess their effectiveness in reducing the risk of personnel contracting respiratory infectious diseases presupposed an understanding of the diffusion mechanism of droplets in the rest lounges. In case 1, when an infected person began to exhale, the droplets were driven upward by an updraft. At the same time, most of the droplets were spread rapidly to the lateral front by the longitudinal body airflow. As the exhilation behavior proceeded, the first person to be affected was the susceptible person on the same side of the infected person's row, and most of the droplets wrapped around that susceptible person. The height of the exhaled droplets moved up to 1.65 m. The transmission of a respiratory infection in a  
Figure 7: Velocity field and streamline tracing in the vertical middle plane (\(\gamma\) = 3 m) and the horizontal plane where the respiratory center is located (Z = 1.1 m). (**a**) Case 1; (**b**) case 2; (**c**) case 3; (**d**) case 4; (**e**) case 5.  
confined space depended on the final number of droplet nuclei transmitting the pathogen, and the results of this part are shown in the following paragraph. At the same time, the droplets were affected by the vortex, and some of them moved downward, with a very small fraction of them moving behind the infectious person. The lateral airflow made the droplets move between the two rows of passengers in the same row, but due to the intermediate partition airflow, the droplets failed to continue spreading to the opposite side of the main air supply, and the droplets were confined to the area in front of the source of infection, and the number of particles in the respiratory zone of the front passengers was much larger than that of the rear passengers. In the simulation calculation of the effect of the hanging curtains, droplets with a particle size of 1 um were used, which are small droplets. Those droplets were virtually unaffected by gravity, could be suspended in space for long periods, and exhibited good flow characteristics, thus increasing the likelihood of infection from inhalation by susceptible people in the front. The number of droplets in front of the rear passenger increased with diffusion time until they spread throughout the lounge and were exhausted through the air vents. In an indoor environment, the trajectory and distribution of droplets were closely related to the airflow field. As demonstrated in Figure 8b-e, the droplets are driven by the airflow and transported along the airflow direction, and the droplets are fully mixed and dispersed in the turbulent flow. Specifically, the curtain separation scheme A blocked the tendency of droplets to spread forward, and the droplet particles were concentrated in the middle of the two baffles in scheme B. Due to the separating effect of the curtain, the droplets in scheme C and scheme D were concentrated in the airflow partition. In case 1, it was demonstrated that in the absence of any physical isolation measures, the number of particles in the x = 0-1.3 m region was significantly higher than that in the x = 1.3-3 m region. The particulate concentration showed an essentially decreasing trend with increasing Y distance, and the number of particles behind the infected person was very limited.