Accession Number:

ADA242459

Title:

Oscillating-Flow Wind Tunnel Studies for a Circulation Control Circular Cylinder

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1991-03-01

Pagination or Media Count:

110.0

Abstract:

A two-dimensional circulation control 4.25-in. diam. x 24-in. span model was designed for installation in the Naval Postgraduate School oscillating flow, low speed wind tunnel. An adjustable, tangential blowing slots was included in the design to provide circulation control capability using the Coanda flow effect aft of the spanwise slot. Orifice locations were defined for obtaining surface static pressures which could be subsequently processed to yield sectional lift and drag coefficients. Pressure system calibrations were also made to determine the dynamic transfer function from a simulation of the models static pressure orifice when connected to the pressure transducer. Similar transfer functions were determined for a static pressure probe. The existing data acquisition system was used to process the sampled digital data sequence. Clear-tunnel flow calibrations were performed in the 2x2x18.6 long test section at a mid-length test station using a hot-wire and the calibrated static pressure probe. An oscillating velocity was superimposed upon a mean free stream motion using an existing rotating mechanism of 4 synchronized shutters at the end of the test section. Analytic estimates of both static pressure and velocity perturbations correlated well with experimental results for a frequency range of 14-40 Hz with a fixed value of shutter blockage.

Subject Categories:

  • Aerodynamics
  • Helicopters

Distribution Statement:

APPROVED FOR PUBLIC RELEASE