Aerodynamic performance of low-to-moderate aspect ratio wings at low Reynolds numbers
This thesis presents wind tunnel results of wings of low-to-moderate aspect ratio (2$\leq$\AR$\leq$5) tested at low Reynolds numbers (40,000 to 160,000). All models tested had a chord length of 3~in and a wingspan of 7 to 17.5~in. Experiments were conducted in the low-turbulence wind tunnel in the Subsonic Aerodynamics Research Laboratory at the University of Illinois at Urbana-Champaign (UIUC). An external three-component platform force balance was designed, fabricated and assembled to perform the experiments. The balance design methodology, calibration methodology, experimental setup, wing mounting setup validation and historical data comparisons are described in detail. Low Reynolds number tests performed on a rectangular wing having an aspect ratio of 4 and using the Wortmann FX~63-137 airfoil showed the existence of a critical Reynolds number of 90,000 for which a jump in performance characteristics was observed. Pre-stall and post-stall hysteresis was captured at the critical Reynolds number. Flow visualization photographs for the Wortmann wing at different angles of attack are presented. Finally, aerodynamic performance measurements taken for ten flat-plate rectangular and tapered wings are also presented and discussed. A detailed analysis of trends from aerodynamic performance measurements taken for the ten flat-plate wings showed a number of interesting effects with respect to Reynolds number, aspect ratio, and taper ratio. No critical Reynolds number and aerodynamic hysteresis was however found for the flat-plate wings in the Reynolds number range tested.
low aspect ratio, low Reynolds number, Aerodynamics, wind tunnel testing
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign