Cavitation Potential of Flow on Stepped Spillways

AbstractCavitation on spillways has proven to be an undesirable condition. The formation of vapor-filled bubbles and cavities and their eminent collapse has led to significant damage to major spillway components and appurtenant structures worldwide. Although stepped spillways are thought to be less prone to cavitation damage than smooth spillways, designers continue conservative practices regarding specifying stepped spillways at many sites. Using laboratory experiments in a specialized reduced ambient pressure chamber, cavitation was shown to form on stepped geometries that are representative of typical stepped spillways currently in service. Experiments in a nonaerated closed conduit revealed the strength and extents of the highly intense shear layer that forms above the step tips, and the friction characteristics were determined and compared with results from previous researchers. Advanced techniques for detecting cavitation characteristics along with high-speed videography have given additional insigh...

[1]  Fabián A. Bombardelli,et al.  Closure of "Skimming, Nonaerated Flow on Stepped Spillways over Roller Compacted Concrete Dams" , 2012 .

[2]  Nallamuthu Rajaratnam,et al.  Characteristics of Skimming Flow over Stepped Spillways , 2000 .

[3]  R. W. Kermeen,et al.  INCIPIENT CAVITATION AND WAKE FLOW BEHIND SHARP-EDGED DISKS , 1957 .

[4]  Allan J. Acosta,et al.  The utilization of specially tailored air bubbles as static pressure sensors in a jet , 1984 .

[5]  M. Tozzi.  Residual energy in stepped spillways , 1994 .

[6]  James W. Daily,et al.  TURBULENCE AND BOUNDARY LAYER EFFECTS ON THE INCEPTION OF CAVITATION FROM GAS NUCLEI , 1955 .

[7]  Hubert Chanson,et al.  Hydraulics of Stepped Chutes and Spillways , 2002 .

[8]  H. L. Dunegan.  MODAL ANALYSIS OF ACOUSTIC EMISSION SIGNALS , 1997 .

[9]  Willi H. Hager,et al.  Two-Phase Flow Characteristics of Stepped Spillways , 2003 .

[10]  Steven L. Ceccio,et al.  The influence of developed cavitation on the flow of a turbulent shear layer , 2002 .

[11]  Hunter Rouse,et al.  CAVITATION IN THE MIXING ZONE OF A SUBMERGED JET , 1953 .

[12]  Roger E. A. Arndt,et al.  Rough Surface Effects on Cavitation Inception , 1968 .

[13]  Masayuki Takahashi,et al.  Flow Characteristics of Skimming Flows in Stepped Channels , 2004 .

[14]  Willi H. Hager,et al.  Bottom Aeration of Stepped Spillways , 2006 .

[15]  Martí Sánchez-Juny,et al.  Developing Flow Region and Pressure Fluctuations on Steeply Sloping Stepped Spillways , 2009 .

[16]  Marcos Tozzi,et al.  Caracterizacao / comportamento de escoamentos em vertedouros com paramento em degraus , 1994 .

[17]  J. Katz,et al.  Pressure fluctuations and their effect on cavitation inception within water jets , 1994, Journal of Fluid Mechanics.

[18]  Sherry L. Hunt,et al.  Energy Dissipation on Flat-Sloped Stepped Spillways: Part 1. Upstream of the Inception Point , 2010 .

[19]  A. J. Peterka,et al.  The Effect Of Entrained Air On Cavitation Pitting , 1953 .

[20]  Y. Hassan,et al.  Drag reduction by microbubble injection in a channel flow , 2008 .