Accession Number:

AD0610634

Title:

THEORETICAL AND EXPERIMENTAL STUDIES OF IMPINGING UNIFORM AND NONUNIFORM JETS

Descriptive Note:

Corporate Author:

CORNELL AERONAUTICAL LAB INC BUFFALO NY

Personal Author(s):

• Brady, W. G.
• Ludwig, Gary R.

Report Date:

1964-08-01

Pagination or Media Count:

108.0

Abstract:

The results of an experimental investigation of the flow under a normally impinging nonuniform jet are presented. The jet velocity profile was designed to be representative of rotors and ducted fans. The jet was tested at distances from the ground of 4, 2, and 12 nozzle diameters. An approximate analysis which uses an empirical relation for radial mass flow near the ground is used to calculate the properties of the flow along the ground at radii large enough so that the pressure gradient is approximately zero. A method of calculating the properties of the flow in an inviscid, normally impinging, uniform jet has been formulated. The formulation is applicable for all distances between the jet nozzle and the ground. Solutions have been obtained for jets at nozzle-to-ground distances of 14 and 1 jet diameters. The mathematical model used was based on a vortex-sheet representation, and solutions were obtained by means of an iterative technique using an IBM 704 digital computer. Good agreement was obtained with experimental ground-plane and jet-centerline pressure distributions, and with nozzle-exit velocity profiles.

Descriptors:

• *JET FLOW
• *VERTICAL TAKEOFF AIRCRAFT
• BOUNDARY LAYER
• DOWNWASH
• DUCTED FANS
• EXHAUST NOZZLES
• EXPERIMENTAL DATA
• FLUID FLOW
• IMPELLERS
• ITERATIONS
• MATHEMATICAL ANALYSIS
• VELOCITY
• VORTICES

Subject Categories:

• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE