A Multi-Diagnostic Approach to Testing V/STOL Craft.
Susan M. Foley, Robert B. Funk, Phillip .A. Fawcett, Narayanan M. Komerath.
AIAA Paper 92-4008, Presented at the AIAA Ground Test Conference, Nashville,
TN, July 1992.
Abstract: The interactive aerodynamics of new V/STOL designs require a new
approach to ground testing, where multiple properties are measured both on
and away from surfaces during continuous changes in test parameters. Using
a set of experiments of increasing complexity, a new capability is demonstrated
for capturing surface pressure, velocity fields and vortex flow features
over a range of test parameters. Two-dimensional velocity fields are captured
over a full-scale UH-1 helicopter stabilator, a wing/canard configuration,
and under the hub of a rotor in forward flight. Surface pressures and vortex
flow features are captured over a wing/rotor configuration. Short tunnel
run-times are achieved at the expense of large computational post-processing
resources. It is shown that such experiments can be performed while the configuration
geometry and flow conditions are continuously varied through a wide range
of parameters. This experiment led to the discovery and capture of massive
flow separation caused by vortex interaction on wings at moderate angles
of attack, large-scale deflection of vortex wake trajectories by wake/wing
interaction, unsteady flows over wings generated by canard interaction, and
quasi-steady separation phenomena caused by the difference in time scales
between separation and reattachment.
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