Developing Flow Region and Pressure Fluctuations on Steeply Sloping Stepped Spillways

Discussion of “Skimming, Nonaerated Flow on Stepped Spillways over Roller Compacted Concrete Dams” by Inês Meireles, Floriana Renna, Jorge Matos, and Fabián Bombardelli

“…Amador et al (2009) noted that critical negative dynamic pressures linked to possible cavitation formation occur near the inception point if the unit discharge q > 15 m 2 =s. If computing the cavitation index σ according to Falvey (1990), based on "average hydraulics" instead of effective local pressures, values as shown in Fig.…”

“…If computing the cavitation index σ according to Falvey (1990), based on "average hydraulics" instead of effective local pressures, values as shown in Fig. 1 result at the inception point for θ ¼ 50°and two common step heights of h ¼ 0.3 and 1.2 m. Based on the limiting discharge of 15 m 2 =s of Amador et al (2009), the critical cavitation index becomes σ c ¼ 0.5 and 0.7 ( Fig. 1), i.e., above the critical value of σ c ¼ 0.2 for smooth chutes.…”

Comparison of Different Turbulence Models for Numerical Simulation of Pressure Distribution in V-Shaped Stepped Spillway

“…Pressure distribution in stepped spillways also became a research focus for negative pressure on the step surface which may lead to cavitation damage. Many scholars have studied the pressure distributions of stepped spillways through physical models, such as Zhang et al [11], Fratino et al [12], Sánchez-Juny et al [13,14], Amador et al [15], Zhang et al [16], and Dhatrak and Tatewar [17] and so on. With the development of computer science and computational technology, the numerical method has become an efficient method to study the pressure distribution of stepped spillways.…”

Hydraulics of the Developing Flow Region of Stepped Spillways. II: Pressure and Velocity Fields

“…5D, 5E & 6). Such sub-atmospheric pressures were recorded by Toombes (2002) immediately below the step edges in nappe and transition flows, and by Sanchez-Juny et al 2008 andAmador et al (2009) Figure 6 presents typical pressure contours above two step cavities. In Figure 6, the locations of pressure measurements are tagged with black dots, except at the free-surface where the pressure was atmospheric.…”