## 4 Results and Discussion
For \(L_{1}\)/\(H_{1}\) = 6.0, filling time of \(t\) = 104.7 s is obtained, while the ratio \((L_{1}\)/\(H_{1})_{\rm o}\) = 35.0 leads to a resin injection time of the once minimized of \(t_{\rm m}\) = 63.5 s, which is about 65.0% faster than the worst-performing geometry. For the lower magnitudes of \(H_{1}\)/\(L_{1}\), resin distribution occurs in a radial form in the upper region of the T-shaped channel and linearly from the center to the side surfaces of the mold at the bottom region of the T-shaped channel. This behavior is quite similar to that seen for I-shaped empty channels with high intrusion in the porous plate. As the ratio of \(H_{1}\)/\(L_{1}\) is changed to \((H_{1}\)/\(L_{1})_{\rm o}\) = 35.0, the radial advancement of the resin at the upper region of the T-shaped channel is found to be intensified, when compared with the previous case (\(H_{1}\)/\(L_{1}\) = 6.0). This effect also intensifies the linear advancement of resin in the inferior region of the porous plate. Consequently, the filling of the resin in the horizontal direction (from the open channel towards the side walls) is completed in a shorter amount of time, also leading to an improvement in resin advancement towards the porous plate exit. However, significant increase in bifurcated length (augmentation of the ratio \(H_{1}\)/\(L_{1}\)) leads to the formation of permanent voids inside the plate. It is worth mentioning that the channel area is constant; as a consequence, augmentation of the channel bifurcated branch leads to a decrease in channel thickness, which is the main factor responsible for the formation of voids, especially in the corners between the single and bifurcated regions of the channel. The variation of the \(L_{1}\)/\(H_{1}\) ratio provides the once minimized filling time (\(t_{\rm m}\)) of the resin in the porous plate for each investigated ratio of \(L_{0}\)/\(H_{0}\) and different ratios of \(H_{0}\)/\(H_{1}\). In the second optimization level, the results of Figure 9 are compiled and presented in Figure 11a,b. Figure 11a illustrates the influence of the ratio \(L_{0}\)/\(H_{0}\) over the once minimized filling time, \(t_{\rm m}\), for different \(H_{0}\)/\(H_{1}\) ratios studied here. It can be noted that for \(H_{0}\)/\(H_{1}\) = 20.0; 30.0 and 40.0, the effect of the \(L_{0}\)/\(H_{0}\) over \(t_{\rm m}\) is similar, except for cases with \(H_{0}\)/\(H_{1}\) = 10.0. In general, it is noticed that lower ratios of \(L_{0}\)/\(H_{0}\) present a predominance in achieving the twice-minimized filling time (\(t_{\rm mm}\)), i.e., the best shapes are obtained when the main channel has a higher penetration in the direction of the exit region of the domain. For the ratio \(H_{0}\)/\(H_{1}\) = 10.0, it can be observed that intermediate ratios of \(L_{0}\)/\(H_{0}\) lead to the best performance of the problem. For the lowest magnitudes of \(L_{0}\)/\(H_{0}\), the optimal ratios of \((L_{1}\)/\(H_{1})_{\rm o}\) suffer a strong decrease (see Figure 11b), degenerating the T-shaped channel into an I-shaped one. For higher magnitudes of \(L_{0}\)/\(H_{0}\), the T-shaped channel is strongly restricted in the lower region of the porous plate. Figure 11b highlights the influence of the ratio \(L_{0}\)/\(H_{0}\) over the once-optimized ratio of \(L_{1}\)/\(H_{1}\), \((L_{1}\)/\(H_{1})_{\rm o}\), for the four different magnitudes of \(H_{0}\)/\(H_{1}\) investigated. The effect of \(L_{0}\)/\(H_{0}\) over \((L_{1}\)/\(H_{1})_{\rm o}\) varied for different magnitudes of \(H_{0}\)/\(H_{1}\). For the ratios \(H_{0}\)/\(H_{1}\) = 20.0; 30.0 and 40.0, the best shapes are obtained for \((L_{0}\)/\(H_{0})_{\rm o}\) = 0.05 and for high magnitudes of \((L_{1}\)/\(H_{1})_{\rm o}\) in the range \(20.0\leq(L_{1}\)/\(H_{1})_{\rm o}\)\(\leq 25.0\), corroborating previous findings that the best performance is achieved for the most elongated possible single and bifurcated branches of T-shaped channel.