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Title: Inflow zone and discharge through propeller jets
Authors: Maynord, Stephen T.
Keywords: Propellers--Environmental aspects--Models
Navigation--Environmental aspects--Models
Illinois Waterway (Ill.)
Mississippi River
Illinois Waterway (Ill.)--Navigation
Mississippi River--Navigation
Publisher: Coastal and Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Interim report for the Upper Mississippi River-Illinois Waterway System Navigation Study;
Abstract: Abstract: The inflow zone and discharge through propeller jets are used in evaluating the environmental effects of navigation on the Upper Mississippi River and Illinois Waterway (UMR-IWW). Both physical and numerical models were used to define the zone of inflow to typical tows used on the UMR-IWW. Results showed that the inflow zone for underway vessels is about 25 m on either side of the centerline of the vessel for the typical three-barge-wide by five-barge-long push tow used on the UMR-IWW. Water in this zone can go through the propellers but not all water in this zone will go through the propellers. Discharge through propeller jets is defined using the momentum theory of propellers design. Equations for discharge are presented based on thrust coefficients and propeller speed and are the most accurate means of defining discharge. However, thrust coefficients are rarely provided by vessel operators and approximate methods for discharge are developed based on applied power. Equations are presented for discharge as a function of applied power, propeller diameter, propeller type, and vessel speed. Equations for discharge based on thrust coefficients are compared to measured velocities for two open-wheel systems and one ducted propeller system. The measured and calculated valves were in agreement.
Description: ENV Report 25
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:ENV Report

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