Tools to Support Design of Coanda-Effect Screens for Debris Exclusion and Fish Protection

Project ID: 19233
Principal Investigator: Tony Wahl
Research Topic: Improving Geotechnical Infrastructure Reliability
Funded Fiscal Years: 2019 and 2020
Keywords: None

Research Question

This project will address two related research questions:
1) Can the flow capacity and associated profiles of flow conditions (depth, velocity, etc.) over Coanda-effect screen structures be predicted analytically for the range of screen slopes, flow conditions, and screen materials encountered in typical applications?
2) Can analytical methods for screen capacity estimation be documented and disseminated via journal articles and a user-friendly computer program that will assist screen designers?

Need and Benefit


¿Reclamation has multiple potential applications for Coanda-effect screen structures, including conversions of flood-
irrigation to sprinkler irrigation, conversions of open canals to pressurized pipelines, dewatering facilities, solids

separation, fish protection and fish handling applications, etc.
¿Previous research by Reclamation (Wahl 2001) advanced the state of the art significantly, but did not address a wide
enough range of flow conditions. The numerical model developed from the latest testing improves the accuracy of
flow measurement predictions from about ±50% to better than ±10%.
¿The new research publications and computer program will reduce designer's time needs dramatically (at least a
factor of 10) compared to performing manual calculations.
¿Without these research results, screen capacities could be poorly estimated, since previous studies considered a
narrow range of hydraulic conditions.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Tools to Support Design of Coanda-Effect Screens for Debris Exclusion and Fish Protection (final, PDF, 5.1MB)
By Tony Wahl
Report completed on September 30, 2020

This research product summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20