Five WLTs with a brimmed-diffuser shroud of CiiB10 [for the brimmed-diffuser CiiB10, Ref. 25] are arranged as an upper- and lower-row configuration in the same vertical plane, i.e., two WLTs (#2 and #4) in the upper row and three WLTs (#1, #3 and #5) in the lower row with equal separations *s* for all gaps, as shown in Fig. 2. Figure 5 shows the results of power coefficient variations with the gap ratio *s*/*D*_{brim}. Each bar at each *s*/*D*_{brim} indicates the increase Δ*C*_{pi} in power output defined by Eq. (3), compared to that for the stand-alone configuration. “AVE” in Fig. 5 means the averaged values of each increase of five WLTs, defined by Eq. (4). Similarly, Fig. 6 shows drag coefficient variations Δ*C*_{di} with the gap ratio *s*/*D*_{brim}. Power coefficient *C*_{pi} and drag coefficient *C*_{di} of each WLT in the five-WLT arrangement increase at all gap ratios, compared to those for stand-alone configuration, *C*_{p}_{0}_{i} and *C*_{d}_{0}_{i}. When WLTs are set up very closely (e.g., *s*/*D*_{brim} = 0.05), variations in the averaged value of $Cpi\xaf$ were a little smaller, compared to other gap ratios. When *s*/*D*_{brim} = 0.20, Δ$Cpi\xaf$ increased by 21% at the maximum. When *s*/*D*_{brim} = 0.15, Δ$Cdi\xaf$ increased 13.6% at the maximum. Variations in $Cpi\xaf$ are larger compared with those in $Cdi\xaf$ at all gap ratios. It is because that the power output is proportional to the cube of wind velocity and the drag force is proportional to the square of it. It should be noted that Δ$Cpi\xaf$ and Δ$Cdi\xaf$ are much larger compared with those for two-WLT MRS and three-WLT MRS [12–14]. From the results of individual increases in *C*_{pi}, Δ*C*_{pi} of #3 is the highest for *s*/*D*_{brim} = 0.05 and 0.1. Δ*C*_{pi} of #2 is the highest for *s*/*D*_{brim} = 0.15, 0.2, and 0.25, as shown in Fig. 5. Similarly, Δ*C*_{di} of #3 are always highest for all *s*/*D*_{brim}, as shown in Fig. 6.