Intro to Cavitation in Chutes and Spillways: On-Demand

The course is intended to give the participants an understanding of cavitation on chutes and spillways. The course will be introduced with a video of a case study that illustrates some of the fundamentals of cavitation and an explanation of why cavitation causes damage. Following the video, a PowerPoint presentation will discuss the beneficial effects of aeration on preventing damage due to cavitation. The participants will be guided to an Excel program that reproduces all the Fortran programs given in EM 42. The spreadsheet can be used to analyze chutes and spillways for their hydraulic and cavitation performance, design aerators, determine the best vertical alignment to minimize cavitation inception, and analyze the cavitation damage potential of historic data. 

Key Takeaways:

  • Understanding of cavitation and how it is formed.
    Understanding of the difference between cavitation and cavitation damage.
    Understanding of dam failure investigations and forensic reporting.
    Beneficial effects of aeration on preventing cavitation damage.
    Required surface tolerance to prevent damage with and without aeration.
    Availability of tools to study cavitation on chutes and spillways.

Henry T. Falvey

Henry T. Falvey & Associates, Inc., Dr. Ing. Honorary Diplomate WRE

Henry T. Falvey has been president of Henry T. Falvey & Associates, Inc for 27 years.  He retired from the USBR after 27 years with the Hydraulics Branch in the Research Division. He was the Senior Research Officer for 2 years with the Ecole Polytechnique Federale de Lausanne. He does both national and international consulting on the hydraulics of dams and has consulted or lectured on cavitation in 12 countries. He is the author of USBR Monograph 42, Cavitation in Chutes and Spillways, 1990. He is a lifetime member of ASCE and a member of both Sigma Xi and the International Association of Hydraulic Research. He has received awards from ASDSO, USSD, ASCE, and the USBR in recognition of his work pertaining to the hydraulics of dams and canals.  

INTRODUCTION

  • Definition of boiling, gaseous cavitation, vaporous cavitation Armstrong Limit
  • Definition of Cavitation Index
  • Distinction between Cavitation and Cavitation Damage

BASIC CONCEPTS

  • Initiation of damage due to surface irregularities
  • Growth of calcite deposits in concrete
  • Bubble Collapse Mechanisms
  • Leap Frog Effect
  • Recognition of Cavitation Damage

MODEL TESTING

  • Physical Model
  • Reduced Pressure Chamber
  • Incipient Cavitation Characteristics of Specific Irregularities

FIELD OBSERVATIONS

  • Historical Extent of Damage
  • Damage Index

DAMAGE PREVENTION

  • Materials
  • Tolerances
  • Air Entrainment
  • AIR SLOT DESIGN
  • Placement
  • Types of Aerators

DESIGN TOOL

  • Computer Program
    • Hydraulics Cavitation
    • Characteristics 
    • Aerator Design
    • Equal Cavitation Number Spillway
    • Sinusoidal Cavitation Number Spillway

Key:

Complete
Failed
Available
Locked
On-Demand Viewing
Open to view video.
Open to view video. This is a recording from the live event. It will be available until 3/12/2020.
Post Survey
5 Questions
5 Questions Post Survey
Completion Quiz
10 Questions  |  3 attempts  |  6/10 points to pass
10 Questions  |  3 attempts  |  6/10 points to pass
Completion Certificate
2.00 PDH credits  |  Certificate available
2.00 PDH credits  |  Certificate available