Unsteady Low-Speed Windtunnel Test of a Straked Delta Wing, Oscillating in Pitch. Part 6. Presentation of the Visualization Program

摘要

Results of a wind tunnel test of an oscillating straked wing. The report provides unsteady airloads and pressure distributions for a range of incidence (-8 to 50 deg.) and amplitudes ( 1 to 16 deg.). The wind speed was 80 meters/second, which provided reduced frequencies up to 0.50 based on root chord. The zeroth and first harmonic as well as the continuous time history of the pressure and overall loads were measured. Flow visualization was performed for flow of 30 meters/second using a pulsating laser light sheet. In part VI results of the flow visualization investigation are presented in the appendix in the form of tables and plots of vortex core positions, both as a function of phase angle during one cycle of oscillation. Table 13a through c in part I provides a convenient cross-reference of test conditions and the table numbers in this part. The phase angles are varied in steps on 45 deg so that a time history is developed during one cycle. When it was impossible to measure vortex core positions, due to either vortex burst or overexposure, no values are given in the tables and plots. Results are presented for the three laser light screen positions. The entries in the table for the aft position near the wing trailing edge are limited because very few core position measurements were possible due to vortex bursting. Keywords: Unsteady flow; Vortex flow; Wind tunnel test. (JHD)