**2. Restaurant configurations**

The restaurant dining area modeled in this study is a rectangular room with a 13 m length, 6 m width, and 3.5 m height. There are seven tables arranged in two rows with four patrons at each table, and a reception desk with a receptionist. The patrons and receptionist are modeled as cuboids of 1 m height and 0.35 m length and width (representing people in a seated position). The layout of the restaurant is shown in **Figure 1** with the COVID-19 carrier marked with red. There are 16 vents with 12 on the ceiling and 4 on the wall opposite to the row with the COVID-19 carrier. The vents on the ceiling are each 0.6 m 0.6 m and the vents on the wall are each 0.4 m 0.8 m. At a given time, four of these vents act as supply vents and four act as return vents. The vent configurations are given in the **Figure 2**. The first configuration has supply and return vents on the ceiling and the supply vents are parallel to the return vents. The supply vents are in a straight line above the tables on one side of the room (above the COVID-19 carrier). The return vents are in a straight line above the opposite row of tables. The second configuration also has both supply and return vents on the ceiling but the return vents are in a straight line in the center of the room, and the supply vents are staggered on both sides of the return vents. In the third configuration, the return vents are on the ceiling above the row of tables on the side of the COVID-19 carrier. The supply vents in this case are on the opposite wall but parallel to the return vents.

The ambient temperature of the room initially is 25°C and the constant supply of air introduced through the vents is at 21°C. Each ceiling vent is divided into four and

**Figure 2.**

*Vent configurations (a) ceiling (S parallel), (b) ceiling (S staggered), and (c) ceiling/wall (S parallel). Blue represents supply vents and green represents return vents.*

air flows through them at a 30° angle from the ceiling in four directions. Each wall vent is divided into two and air flows through them at 30° from the horizontal and 45° from the wall in two opposite directions. The patrons are modeled with a heat flux of 1224.5 kW from their top surface to represent heat release from their head.
