Initial Unsteady Aerodynamic Measurements of a Circulation Controlled Airfoil and an Oscillating Flow Wind Tunnel.
Abstract
Steady state results of lift developed by varying the momentum blowing coefficient C sub mu upon a refurbished Circulation Control Rotor (CCR) airfoil section were favorable. This thesis was an experimental investigation to quantitatively evaluate whether the steady state results could be applied by a quasi-steady assumption when a harmonic perturbation of C sub mu was superimposed upon the steady value. Results suggested an attenuation in the dynamic transfer function of dC sub P/d C sub mu as the oscillating blowing frequency was increased. Initial measurements indicated that the RMS C sub P perturbation was an order of magnitude greater than the normalized RMS velocity perturbation. To further clarify this situation, investigations were conducted to establish a dynamic frequency response calibration of the wind tunnel. Results confirmed the order of magnitude difference between the RMS C sub P and normalized RMS velocity perturbations, indicating, that the tunnel flow environment was governed by Euler's equation in its complete form rather than with the simplifications which lead to the quasi-steady small perturbation theory.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1977
- Accession Number
- ADA042102
Entities
People
- Emmett John Lancaster
Organizations
- Naval Postgraduate School