Pressure and velocity distributions in plunge pools
Date
2016-09
Authors
Castillo, Luis G., author
Carrillo, José M., author
Colorado State University. Department of Engineering, publisher
Journal Title
Journal ISSN
Volume Title
Abstract
When dam overtopping produces rectangular free jets that discharge into plunge pool basins below the dam, the pressure and velocity distributions of the flow in the plunge pool must be estimated to evaluate potential scour that might destabilize the dam. The high turbulence and aeration phenomena that appear in falling jets and dissipation basins make it difficult to carry out studies based only on classical methodologies. This work addresses plunge pool flows, and compares numerical results against our own experiments. Instantaneous pressures, velocities and air entrainment were obtained with the use of piezoresistive transducers, Acoustic Doppler Velocimeter and optical fiber, respectively. Mean velocity field and turbulence kinetic energy profiles were determined. To identify the level of reliability of models, numerical simulations were carried out by using the "homogeneous" model of ANSYS CFX, together with different turbulence closures. The numerical results fall fairly close to the values measured in the laboratory, and with expressions for submerged hydraulic jumps and horizontal wall jets. The observations can be well predicted for horizontal velocities greater than 40% of the maximum velocity in each profile, and when the ratio of the water cushion depth to the jet thickness is lower than 20.
Description
Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.
Includes bibliographical references.
Includes bibliographical references.
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Subject
air entrainment
free falling jets
impingement jets
laboratory
numerical simulations
overtopping