Study of Rotor Wakes at Very Low Advance Ratios.
Final rept. 30 Jun 76-30 Jun 79,
OHIO STATE UNIV COLUMBUS DEPT OF MECHANICAL ENGINEERING
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With the recognition of the importance of operation of military helicopters at very low altitudes and very low velocities, the need for data on airflow under these conditions became apparent. Work was initiated to obtain data at very low advance ratios typical of such low speed helicopter flight. The original goals of the research were to try to obtain a description of the flow field both time averaged and instantaneous. Because of prior experience with hot wire anemometry the effort was directed towards using a hot wire probe to get all three components of velocity. The effort resulted in an operational rotor drive and measuring system, a probe calibration and positioning system, frequency response determination, and acquisition of average value data. The low speed flow fields found demonstrated a squirting affect that could be seen on both sides of the rotor at very low advance ratios. Two non-steady data acquisition systems were considered, one developed to the point of use but was found awkward to use, and a second interactive system which progressed to the point that initial tests using it in a time average mode illustrated the interactive capability. Author
- Computer Hardware
- Fluid Mechanics