## 2 Method
### Case Design and Boundary Conditions  
A fully occupied, single-aisle aircraft cabin containing seven rows of seats was chosen for study. The dimension of the cabin was 5.852 m (Z) \(\times\) 3.253 m (X) \(\times\) 2.155 m (Y). A total of 42 thermal manikins were seated inside the cabin. The size of the manikin was close to \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Airplane Model** & **Seat Number** & **Seat Shape** & **Seat Structure** & **Manikins** & **Method** & **References** \\ \hline Unknown & 49 in 7 rows & Simplified Seats & All seats inclined (15\({}^{\circ}\)) & Rectangular boxes & CFD & [PERSON], 2010 [26] \\ B787-9 & 39 in 5 rows & Simplified Seats & All seats lying flat & Cylinders & CFD & Wang, 2021 [27] \\ B737 & 60 in 10 rows & Realistic airplane seats & All seats inclined (12.1\({}^{\circ}\)) & Cylinders & CFD & [PERSON], 2021 [23] \\ B737 & 3 in 1 rows & Realistic airplane seats & All seats inclined (unknown angels) & Realistic body & CFD & [PERSON], 2021 [25] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of inclined seats in representative published studies. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Airplane Model** & **Seat Number** & **Reasons for Asymmetric Structure** & **Seat Shape** & **Seat Structure** & **Manikins** & **Method** & **References** \\ \hline Unknown & 21 in 3 rows & Seat occupancy rate: 15/21 & Simplified Seats & Upright & Rectangular boxes & CFD & Wan, 2009 [14] \\ Unknown & 28 in 4 rows & Seat occupancy rate: 14/28 & Simplified Seats & Upright & Rectangular boxes & CFD & [PERSON], 2009 [15] \\ Unknown & 18 in 4 rows & Seats staggered & Simplified Seats & Upright & Rectangular boxes & CFD & [PERSON], 2008 [16] \\ MD-82 & 25 in 5 rows & 3 + 2 passengers in each row & Realistic airplane seats & Upright & Realistic body profiles & Measurement & [PERSON], 2016 [22] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of asymmetric seat layouts in representative published studies. an adult, with a sitting height of 1.26 m and a total surface skin area of 1.91 m\({}^{2}\). All of the seats and manikins were upright and symmetric in the reference case, as shown in Figure 1. Conditioned air was supplied into the cabin from the slot opening below the ceiling on both sides. The cabin air was extracted from the slot outlets near the floor. The width of the side air-supply opening was 15 mm. The air-supply direction was slightly downward at a 30 degangle from the horizontal direction. The width of the bottom air-exhaust opening was 65 mm. ASHRAE Handbook [28] recommends a minimum flow rate of 9.4 L/s per passenger. Therefore, the total air supplied into the cabin was 1436 m\({}^{3}\)/h, corresponding to an average ventilation rate of 9.5 L/s per person. The cabin geometric model and the adopted design parameters were identical to those used in our previous measurement study [20]. To investigate the impact of the seat layout on the cabin flow and the airborne pollutant transport, both the seat inclination and the seat misalignment were studied. The seat inclination was divided into three scenarios. Figure 2a addresses the scenario with three adjacent seats 4A to 4C inclined. Figure 2b presents the scenario with all of the seats A to C in half a cabin inclined, while in Figure 2c all of the seats in the whole cabin were inclined. When inclining the seats, the seats were pressed backward with the seatback inclined 30 deg from the vertical position. The misalignment of the seats across the aisle is illustrated in Figure 2d without inclining the seats. This was to examine the impact of only the seat misalignment on the flow and pollutant transport. Table 4 summarizes the case design in this investigation. Case 1 was set as the standard reference case, with all of the seats in an upright and symmetric layout. Cases 2 to 4 addressed the seat inclination, while the seat misalignment was considered in Case 5. When inclining the seats, the manikins were also inclined with their backs against the seatbacks.