## 3 Results and Discussion
### Computational Simulation  
A real CBP barn found in Kentucky (1.35 m \(\times\) 1.20 m \(\times\) 0.27 m) with five different ridge types and four wind directions was used in CFD simulations, where the average air velocity outside the CBP barn was 0.04 m s\({}^{-1}\) and heat flux of the floor (all compost area) was 0.1 W m\({}^{-2}\). The inlet air velocity used in the model was computed using similitude theory, obtaining a value of 0.1 m s\({}^{-1}\). The calculated values obtained using similitude theory for an open CBP barn without dairy cattle and subjected to natural ventilation were used to assign the boundary conditions of the model: 0.1 m s\({}^{-1}\) average inlet air speed, 6.9 \({}^{\circ}\)C air inlet temperature, 101.325 kPa atmospheric pressure and 0.1 W m\({}^{-2}\) heat flux floor. The air velocity distribution in a vertical plan situated in the center of the barn allows us to determine the inside air speed more precisely. Figure 8 shows the simulated air velocity vectors vertically inside and around of CBP barns equipped with closed ridge (CLR) using a different wind direction. Visually, the simulation results for east to west wind direction were very similar to west to east wind direction, thus, only the east to west wind direction is shown. Figure 8A shows the air entering the CBP barn through the ridge opening at one side, and then coming out through the sidewall opening located at the other side. So, the airflow velocity was reduced due to the presence of the wall and fences on both sides of the barn. It resulted in an internal vortex at the center of the feed alley and compost area. Figure 8B shows the effect of airflow the compost surface area near the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ridge** & **Equations** & **R\({}^{2}\)** & **Equations** & **R\({}^{2}\)** \\ \hline \multicolumn{5}{c}{Air speed of 0.1 m s\({}^{-1}\)} \\ \hline CLR & V\({}_{\text{sim}}\) = 0.8598 V\({}_{\text{mes}}\) + 0.00130 & 0.774 & T\({}_{\text{sim}}\) = 0.9830 T\({}_{\text{mes}}\) + 0.4310 & 0.982 \\ OPR & V\({}_{\text{sim}}\) = 1.1416 V\({}_{\text{mes}}\) + 0.0004 & 0.794 & T\({}_{\text{sim}}\) = 0.7181 T\({}_{\text{mes}}\) + 6.4647 & 0.766 \\ ORC & V\({}_{\text{sim}}\) = 0.9035 V\({}_{\text{mes}}\) + 0.00440 & 0.915 & T\({}_{\text{sim}}\) = 0.8344 T\({}_{\text{mes}}\) + 3.6989 & 0.729 \\ ELR & V\({}_{\text{sim}}\) = 1.0833 V\({}_{\text{mes}}\) - 0.00110 & 0.892 & T\({}_{\text{sim}}\) = 0.6528 T\({}_{\text{mes}}\) + 8.1661 & 0.617 \\ OVR & V\({}_{\text{sim}}\) = 0.9332 V\({}_{\text{mes}}\) - 0.00890 & 0.855 & T\({}_{\text{sim}}\) = 0.7092 T\({}_{\text{mes}}\) + 7.1421 & 0.709 \\ \hline \multicolumn{5}{c}{Air speed of 1.0 m s\({}^{-1}\)} \\ \hline CLR & V\({}_{\text{sim}}\) = 0.9041 V\({}_{\text{mes}}\) + 0.0286 & 0.909 & T\({}_{\text{sim}}\) = 0.7194 T\({}_{\text{mes}}\) + 6.7294 & 0.607 \\ OPR & V\({}_{\text{sim}}\) = 0.9905 V\({}_{\text{mes}}\) - 0.0044 & 0.949 & T\({}_{\text{sim}}\) = 0.6794 T\({}_{\text{mes}}\) + 7.7582 & 0.704 \\ ORC & V\({}_{\text{sim}}\) = 1.0093 V\({}_{\text{mes}}\) - 0.0093 & 0.905 & T\({}_{\text{sim}}\) = 0.6695 T\({}_{\text{mes}}\) + 8.0744 & 0.701 \\ ELR & V\({}_{\text{sim}}\) = 0.8159 V\({}_{\text{mes}}\) + 0.0393 & 0.856 & T\({}_{\text{sim}}\) = 0.4938 T\({}_{\text{mes}}\) + 12.547 & 0.602 \\ OVR & V\({}_{\text{sim}}\) = 0.9329 V\({}_{\text{mes}}\) - 0.0065 & 0.875 & T\({}_{\text{sim}}\) = 0.5571 T\({}_{\text{mes}}\) + 10.949 & 0.525 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Adjusted equations between the values of air velocity measured (V\({}_{\text{mes}}\)) and simulated (V\({}_{\text{sim}}\)), and air temperature measured (T\({}_{\text{mes}}\)) and simulated (T\({}_{\text{sim}}\)) using air speed of 0.1 m s\({}^{-1}\) and 1.0 m s\({}^{-1}\), and five ridge events. alleyway. In Figure 8C, it can be seen a considerable variation in the direction of the air velocity vectors. Inside of the trusses structure, it can be seen that the main flow tends to turn opposite to the main wind direction.