Diagnostic Techniques for Maneuvering Rotorcraft
Army Research Office
Computations and traditional measurement tools are far too slow and expensive
to detect and understand all the aerodynamic interactions encountered by
rotorcraft over the vast range of parameters in transitional maneuvers.
We are learning to extract instantaneous 2-D velocity fields, vortex trajectories,
and configuration geometry from the same video images using inexpensive
white-light sources over large areas typical of rotorcraft and wind turbine
flows. Besides obvious benefits in aircraft development, this opens up
large-area atmospheric boundary layer turbulence phenomena. The issues
are in optimizing resolution, and in the possibilities inherent in iterative
and interactive analysis of space-and time-dependent multiple property
fields. The Spatial Correlation Velocimetry technique offers iterative
extraction of turbulence scales and basic flow metrics such as dilatation
( in reacting flows), eddy lifetimes and histories, and rotation, in high-Reynolds
number, highly unsteady flows. These techniques use personal computers
for initial results, followed by iterations on distributed-processor computers.
Recently we have demonstrated successful application of the technique to
rotor flowfield measurement in a large industry facility, without using
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