## 4 Pressure Characteristics on the Gate Panel  
### The Pressure Distribution Characteristics on the Gate Panel  
#### 4.1.1 Pressure Time-Domain Analysis  
Figure 5 shows the time-domain process of the seven pressure measurement points on the radial gate model at e = 10%, with H = 79.0 m. It can be observed in the figure that the amplitude of the time-domain process at each measurement point is markedly different, yet they all exhibit pronounced fluctuations. There is no universal standard for distinguishing between Gaussian and non-Gaussian water pressure distributions for practical applications. In the present study, [PERSON] et al. (2018) proposed the criteria kurtosis coefficient (C\({}_{\rm E}\)) > 3.5 and skewness coefficient (C\({}_{\rm S}\)) > 0.5 to define the area of deviation from the Gaussian distribution. As depicted in Figure 6, the C\({}_{\rm E}\) of the two typical measurement points exceeds 3, indicating that the overall data distribution is steeper and more concentrated in the center. However, the C\({}_{\rm S}\) of the two measurement points exhibit one value greater than 0 and one less than 0. This analysis suggests that the fluctuating pressure exhibited by the gate panel is consistent with a normal distribution. Figure 4: Layout of pressure measurement point (unit: mm). Figure 5: Pressure distribution of the gate panel measuring points (e = 10%, H = 79 m). The amplitude and distribution pattern of fluctuating pressure serve as the basis for calculating dynamic loads in the design of structures [32]. Typically, the RMS value of fluctuating pressure is used to describe it, which reflects the energy or intensity of the signal. Figure 7 illustrates the pressure distribution characteristics at points near the bottom edge for various gate openings. Points 1 and 2 demonstrate a pattern of initial decrease, followed by an increase and then a subsequent decrease as the gate opening degree increases. With the exception of openings at 90%, it is evident that as the gate opening increases, the root mean square (RMS) of the fluctuating pressure at points 1 and 2 gradually rises. This indicates that the fluctuation intensity of the flow near the bottom edge increases with the increasing gate opening. Furthermore, additional analysis reveals that the rise in the RMS at the measurement points is minimal when the gate opening is less than 65% but becomes pronounced when the opening exceeds 70%. These findings suggest that as the gate opening increases, the turbulence of the water body near the bottom edge becomes more prominent. Figure 8 illustrates the pressure distribution characteristics at seven measurement points on the gate panel under five different upstream water levels. Contrary to the pressure near the bottom edge (P1 and P2), as well as in the middle and upper portions, it is evident  
Figure 6: Typical probability density distribution of measurement points. Figure 7: Pressure distribution at measuring points near the bottom edge of the gate at different openings: (**a**) time-average pressure; (**b**) fluctuating pressure. that the time-averaged pressure on the panel is higher in the center under each water level (P3, P4, and P5). It is worth noting that the aforementioned distribution differs significantly from the gate's hydrostatic pressure distribution. This discrepancy arises from the considerably higher velocity near the bottom, as per Bernoulli's equation, leading to a lower pressure head at the bottom compared to the middle. As depicted in Figure 8b, the RMS of fluctuating pressure near the bottom is substantially higher than that in the middle and the top, indicating a higher fluctuating pressure near the bottom compared to the middle and the top. Moreover, the combination of Figures 7 and 8 illustrates that the loads acting on the gate panels are predominantly time averaged, with the RMS of fluctuating pressure constituting less than 10% of the time-averaged pressure.