An experimental study of blade tip vortices

Flow visualization of oil smoke and pigmented oil using blade tip vortice

A theoretical study of the application of jet flap circulation control for reduction of rotor vibratory forces

The results of a study to investigate the theoretical potential of a jet-flap control system for reducing the vertical and horizontal non-cancelling helicopter rotor blade root shears are presented. A computer simulation describing the jet-flap control rotor system was developed to examine the reduction of each harmonic of the transmitted shears as a function of various rotor and jet parameters, rotor operating conditions and rotor configurations. The computer simulation of the air-loads included the influences of nonuniform inflow and blade elastic motions. (no hub motions were allowed.) The rotor trim and total rotor power (including jet compressor power) were also determined. It was found that all harmonics of the transmitted horizontal and vertical shears could be suppressed simultaneously using a single jet control

Analysis of measured airfoil pressure distributions

A method for evaluating the Glauert coefficients from airfoil pressure distributions is investigated. The linear operating range of the airfoils in steady-state and periodic operating conditions are considered. A rational method for quantitatively characterizing airfoil pressure distributions relative to their geometry and aerodynamic operating environment is developed. The characteristics of the airfoil operating environment is determined from its measured pressure distribution

Spanwise loading distribution and wake velocity surveys of a semi-span wing

The spanwise distribution of bound circulation on a semi-span wing and the flow velocities in its wake were measured in a wind tunnel. Particular attention was given to documenting the flow velocities in and around the development tip vortex. A two-component laser velocimeter was used to make the velocity measurements. The spanwise distribution of bound circulation, three components of the time-averaged velocities throughout the near wake their standard deviations, and the integrated forces and moments on a metric tip as measured by an internal strain gage balance are presented without discussion