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Effect of grazing flow on steady-state resistance of isolated square-edged orificesSteady state diagnostic testing of an isolated orifice has shown the nature of the interaction between grazing and orifice flow causing the large increase in orifice resistance for both inflow and outflow. A simple inviscid interaction model is developed which uses thin aerofoil theory to account for pressure forces exerted at the interface between the orifice and grazing flow together with a one-dimensional discharge coefficient concept. The effect of grazing flow boundary layer thickness is also included in the model. Resistance measurements for each orifice tested, over a wide range of grazing flow speeds and flow rates, collapse into a single curve when plotted in terms of effective discharge coefficient against orifice to grazing velocity ratio. The correlation curves for inflow and outflow are different. Data for clustered orifices collapse in the same way as those for the single orifice. The effect of boundary layer thickness is compared with model predictions.
Document ID
19760015890
Document Type
Contractor Report (CR)
Authors
Rogers, T. (Hersh Acoustical Engineering, Inc. Chatsworth, CA, United States)
Date Acquired
September 3, 2013
Publication Date
April 1, 1976
Subject Category
ACOUSTICS
Report/Patent Number
NASA-CR-2681
Funding Number(s)
CONTRACT_GRANT: NAS3-17858
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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