Drag and Flutter Characteristics of Loop Membranes

摘要

We present the results of experimental investigations on the aerodynamic characteristics of high-drag devices with flexible membranes joined at their short ends (loops). The loops were placed in a low-speed wind tunnel and tested at speeds up to 19 m/s. The range of Reynolds numbers was Re = 2 x 10~5 - 2 x 10~6. The loops were tested for a variety of aspect ratios, from 3.3 to 30, three planform areas, and two mounting methods. Results are presented for the drag coefficient and for the flutter characteristics. We prove that with a low aspect ratio the loops form a teardrop shape and their flutter mode is a sinusoidal-like oscillation. Furthermore, the drag coefficient decreases with the increasing wind speed, but it depends strongly on the aspect ratio and the planform area. Empirical correlations for the drag coefficient are polynomial equations.