Abstract
SPILLWAY SURFACE PROTECTION FROM CAVITATION DAMAGES
Novikova Inna* and Kupriyanov Vladimir
ABSTRACT
The damage caused by cavitation is a significant issue for high-headspillways. Examples have been cited where the extent of damage wasso substantial that further operation of the spillways without restorationbecame impossible. Existing methodologies for detecting cavitationrisk in spillway structures rely on average water flow velocities,leading to inflated requirements for permissible velocities. This articlepresents the results of the authors' laboratory research on the conditionsof appearance and progression cavitation behind offsets of varyingheights. Cavitation index was calculated based on fixed pressures andvelocities in the boundary layer at offset height. The theory of ideal liquid jets was applied toconvert cavitation indices, recorded in limited-size cavitation chambers, into indicesapplicable to unbounded natural flow. Visual observations of cavitation cavity developmentwith increasing velocities enabled the identification of the most hazardous cavitation phases.Recommendations are provided for safeguarding spillways against cavitation damage, takinginto account the impact of hydrodynamic pressure, flow velocity in the boundary layer atoffset height, material strength, flow surface aeration, and the duration of water flow.
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