## 3 Results
### Analysis of Ventilation Rate Results  
The ventilation rate for a naturally cross ventilated low rise isolated building with one effective inlet and one effective outlet can be determined using the following equations [45]. The airflow coefficient, \(C_{Q}\) was computed by Equation (6) with a reference velocity, \(u_{ref}\) of 6.97 m/s and the discharge coefficient, \(C_{d}\) of 0.62 [46]. \[C_{Q}=u_{ref}C_{d}\sqrt{\Delta C_{p}} \tag{6}\]  
where, \(\Delta C_{p}\) denotes the difference in pressure coefficients between the windward and leeward openings, as defined by Equation (7). \[\Delta C_{p}=C_{p,windward}-C_{p,leeward} \tag{7}\]  
Moreover, the flow coefficient, \(C_{Q}\) was employed in Equation (8) for the purpose of calculating the actual flow coefficient, \(C_{a}\). Figure 28: Comparison between the streamwise U/U\({}_{\text{ref}}\) along the centerline of the building models for varying opening positions. \[C_{a}=\frac{C_{Q}}{1+C_{Q}} \tag{8}\]  
Lastly, the ventilation rate, \(Q\) can be obtained by utilizing Equation (9). \[Q=u_{ref}A_{e}C_{a} \tag{9}\]  
where \(A_{e}\) is the area of the opening and is calculated by Equation (10). \[A_{e}=\frac{A_{inlet}\cdot A_{outlet}}{\sqrt{A_{inlet}^{2}+A_{2}^{outlet}}} \tag{10}\]  
\(A_{inlet}\) and \(A_{outlet}\) are the area of the inlet and outlet openings respectively. In Figure 29, the ventilation rate (Q) and normalized ventilation rate (Q/Q\({}_{\text{ref}}\)) values for cross-ventilated isolated building models with fixed outlet window sizes and variable inlet window sizes were visualized using color intensities to facilitate quick understanding of the differences between models. When examining the ventilation rates calculated for the building models WO1, WO2, WO3, WO4, and WO5 used in the study, it is clear that an increase in inlet opening size directly affects ventilation efficiency. The WO5 building model with the highest ventilation rate of 0.004089 m\({}^{3}\)/s was the most efficient model in terms of natural ventilation. In fact, this value clearly indicated that a larger inlet opening size increased the indoor air circulation. The WO4 model ranks second with a ventilation rate of 0.003814 m\({}^{3}\)/s. The high ventilation performance of the WO4 and WO5 models showed that larger inlet openings enhanced the indoor air movement, thus promoting more fresh air circulation within the building. Therefore, it can be concluded that the performance of natural cross ventilation was sensitive to the size of the inlet opening and the airflow improved significantly with larger inlet sizes. The WO3 model, which ranked third with a ventilation rate of 0.003021 m\({}^{3}\)/s, showed a higher performance than the WO2 and WO1 models with smaller openings but a lower performance compared to the WO4 and WO5 models, showing a medium level of success. This result showed that medium sized inlet openings provided a certain level of ventilation efficiency, although insufficient to achieve maximum performance. The WO2 model ranked fourth with 0.001666 m\({}^{3}\)/s, while the WO1 model exhibited the lowest ventilation performance with 0.000418 m\({}^{3}\)/s. The narrow inlet opening in the WO1 model had a limiting effect on ventilation and prevented sufficient air intake. From this, it can be clearly stated that small inlet openings were insufficient for natural ventilation, which could reduce the indoor air quality. The WO1 model should be avoided where ventilation performance is a priority. According to the results obtained above, it can be concluded that the size of the window opening has a critical importance in the natural ventilation performance of the building. Window openings need to be carefully designed if ventilation efficiency is to be improved. Since the WO5 model with a high ventilation rate is suitable for maximizing indoor air quality, it can be preferred for situations where optimum ventilation performance is targeted.