## 3 Results and Discussion
### Computational Simulation
In addition, a lower pressure area was created above the roof in the east and west winds than in the south and north winds, thereby generating higher ridge opening flows. Figure 11: Air velocity vectors obtained in the CFD simulation of the CBP barn equipped with elevated ridge (ELR) and using three wind directions—WDs: (**A**) south to north, (**B**) north to south and (**C**) east to west. Figure 10: Air velocity vectors obtained in the CFD simulation of the CBP barn equipped with chimney (ORC) and using three wind directions—WDs: (**A**) south to north, (**B**) north to south and (**C**) east to west. Figure 12 shows a representation of air velocity vectors distribution vertically when overshot ridge (OVR) was equipped in different wind directions. The recirculation zone of the airflow formed above the roof in simulated barn with south winds (Figure 12A) was smaller than simulated barn with north winds (Figure 12B). Therefore, as can be seen in Figure 12C, the recirculation zone was situated after the barn at windward gable wall height in the simulated barn with east and west winds. The south and north winds direction created the lowest air velocity values differences (Figure 12A,B) and east and west winds produced the highest air velocity values differences (Figure 12C). Airflow entered through both sides the opening wall and owing to density differences between the inside and outside air, it immediately dropped to the floor. Single-sided ventilation tended to show comparatively lower air change rates but increased recirculation zone intensity on the surface of cover (Figure 12A,B). This airflow then travelled toward the center of the building, heating up as it passed over the compost area before it eventually rose. A similar observation has already been reported by [PERSON] et al. (2017). Figure 13 shows the air velocity distribution in a vertical plan situated in the center of the CBP barn simulated equipped with different types of ridge vents for four wind directions. As evidenced in Figure 13A for the CBP barn equipped with closed ridge (CLR), the higher air velocity values was observed near to the compost area in east and west winds. However, in the near ridge region, both these winds directions failed to perform well with air velocity values around 0.1 m s\({}^{-1}\). The findings were sensitive to slight wind direction changes and therefore significant variation was found for all parameters measured. For the CBP barn equipped with open ridge (OPR; Figure 13B), the examination of the air velocity inside the barn above the compost bedding surface demonstrated that the values were very close at 0.2 m height from the ground. However, it can be observed that the air velocity values in the directions of the southerly and northerly winds rapidly increase in the ridge area. For the CBP barn equipped with open ridge with chimney (ORC; Figure 13C), the air velocity value above the compost area was lower in the south and north wind direction due to the drag effect of the sidewall planks. The air velocity values were lower near ridge opening in the east and west wind direction. For the CBP barn equipped with an elevated ridge (ELR), Figure 13D shows that the average air speed in the space between the top of the compost area and the barn roof was approximately half that of the outside wind, for all wind directions. Air velocity was much lower inside the barn than outside and its flow through ridge opening was systematically higher in the south and north wind directions. Finally, for the CBP barn equipped with overshot ridge (OVR; Figure 13E), the air velocity shows approximately the same values at 0.02 m above the compost area for all the wind directions tested, but values strongly decreased near the ridge opening in the east and west wind direction, then increased progressively from the ridge opening. Figure 12: Air velocity vectors obtained in the CFD simulation of the CBP barn equipped with overshot ridge (OVR) and using three wind directions—WDs: (**A**) south to north, (**B**) north to south and (**C**) east to west.