**Appendix A**

A grid resolution study was performed to get an estimate of the error and accuracy of the results. A grid convergence index (GCI) study was conducted using three meshes described in **Table 3**. The geometry modeling and meshing was created using Ansys ICEM. Tetrahedral meshes created in ICEM were converted to polyhedral meshes in Ansys Fluent [19]. The geometry used is the same as that of the restaurant shown in **Figure 1**. The Ceiling (S parallel) vent configuration was simulated for 6 air changes per hour, where ACH refers to the number of times the entire volume of air in the room is replaced by supply air. The COVID-19 carrier sneezes at 14 s after the start of the simulation and the percentages of sneeze particles airborne at the end of 60 s were compared for the three meshes. The time-averaged velocity and temperature profiles for three positions in the room are analyzed and **Figure 11** shows the locations. **Figure 12** shows the temperature profiles and **Figure 13** shows the velocity profiles at the three positions for the three meshes. GCI calculated using the percentage of airborne particles is given in **Table 4**. The fine, medium and coarse mesh are associated with numbers 1, 2, and 3, respectively, and *GCI*<sup>21</sup> refers to the error between the fine and medium mesh and *GCI*<sup>32</sup> refers to the error between the medium and coarse mesh. The procedure for this is detailed in Celik et al. [20]. The mesh size, *h* is given by:

$$h = \left[\frac{1}{N} \sum\_{i=1}^{N} (\Delta V\_i) \right]^{1/3} \tag{10}$$


**Table 3.** *Mesh resolution details.*

**Figure 11.**

*(a) Positions where velocity and temperature profiles are compared, and (b) medium mesh sample.*

**Figure 12.**

*Temperature profiles at (a) position 1, (b) position 2, and (c) position 3 for coarse (green, solid line), medium (red, dashed line), and fine (blue, dash dot dot line) mesh.*

**Figure 13.**

*Velocity profiles at (a) position 1, (b) position 2, and (c) position 3 for coarse (green, solid line), medium (red, dashed line), and fine (blue, dash dot dot line) mesh.*

*Assessing Ventilation Strategies to Reduce the Spread of Pathogens in Restaurants DOI: http://dx.doi.org/10.5772/intechopen.109634*


#### **Table 4.**

*Percentage of airborne particles.*

where *N* is the total number of cells and Δ*Vi* is the volume of the *i th* cell.

The error in the percentage of particles is less than 10% as shown in **Table 4**. While there is some difference between the medium and fine meshes as seen from the velocity and temperature profiles (**Figures 12** and **13**), the computational time for fine mesh is very large. Hence, the medium mesh was selected for the study.
