## 4 Results and Discussion
Figure 6b shows the influence of \(\phi\) on the optimal ratio of \(L_{0}/H_{0}\) named (\(L_{0}/H_{0}\))\({}_{\text{o}}\). It is also noted that the behavior of the geometric ratio (\(L_{0}/H_{0}\))\({}_{\text{o}}\) is modified with the variation of the area occupied by the channel, i.e., there is no universal optimal geometry that leads to the best performance for all area fractions of the open channels. To illustrate the influence of \(\phi\) and the \(L_{0}/H_{0}\) ratio over resin flow considering the I-shaped channel, Figures 7 and 8 show the behavior of the resin advancement for three different instants of time at \(\phi\) = 0.01 and 0.1, respectively. The red region represents the resin, i.e., when the volume fraction is \(f\) = 1.0, while the blue region represents the air (\(f\) = 0). Regions with different colors represent resin/air mixture with intermediary volume fractions between resin and air (0.0 \(<\)\(f\) < 1.0). It is worth  
Figure 5: Effect of the \(L_{0}/H_{0}\) ratio over resin infusion filling time for different area fractions of the I-shaped empty channels. Figure 6: Effect of empty I-shaped channel area fraction (\(\phi\)) over: (**a**) once minimized filling time (\(t_{\text{m}}\)), (**b**) once optimized \(L_{0}/H_{0}\) ratio, (\(L_{0}/H_{0}\))\({}_{\text{o}}\). mentioning that this description is applied to all figures where the resin volume fraction is illustrated. Channel configuration is illustrated with the black line. Figure 7 shows resin advancement for \(\phi=0.010\) and three different magnitudes of the ratio \(L_{0}\)/\(H_{0}\): \((L_{0}\)/\(H_{0})_{\rm o}=0.015\), \(L_{0}\)/\(H_{0}=1.0\) and \(L_{0}\)/\(H_{0}=90.0\), which represents the two extreme magnitudes and an intermediate value of the ratio \(L_{0}\)/\(H_{0}\), where the worst performance was reached. Three different instants of time are illustrated to show resin impregnation along time \(t=20.0\) s (Figure 7a); 60.0 s (Figure 7b) and 100.0 s (Figure 7c). Figure 8 shows the resin flows for \(\phi=0.100\) and two different ratios of \(L_{0}\)/\(H_{0}\): \((L_{0}\)/\(H_{0})_{\rm o}=0.11\) and \(L_{0}\)/\(H_{0}=7.0\), representing the optimal geometry and worst case for three different instants of time: \(t=20.0\) s (Figure 8a), 40.0 s (Figure 8b), and 60.0 s (Figure 8c). Results of Figures 7 and 8 indicated that for the smallest ratios of \(L_{0}\)/\(H_{0}\), there is a higher advancement of resin in the \(y\)-direction. After the spread of resin along the entire empty channel, resin flows from the central region of the domain towards the lateral surfaces of the porous plate. Furthermore, in the superior region of the empty channel, the behavior of the resin flow is similar to that found in radial configurations. This behavior makes the distribution of the resin in the fibrous medium more efficient, minimizing resin filling time in the porous medium. It is also noticed that there are no void formations that could delay the infusion process or cause problems in the manufacturing process. For the highest magnitudes of \(L_{0}\)/\(H_{0}\), the channel is placed in the lower region of the porous plate, leading to an almost constant front-line of resin. Moreover, resin advances towards the exit of the porous domain with a behavior similar to the rectilinear case. In a general sense, geometrical investigation of I-shaped empty channels has attested that the elongated channels in resin propagation direction led to the best performance due to the increase of pressure gradient imposed inside the mold. This behavior is in agreement with the constructal principle of the optimal distribution of imperfections.