Oscillation Pattern of Parachute and Concave Body

Abstract

In this study, the experiment for the oscillation of a parachute after inflation process is done at low Reynolds number. Especially, effects of the payload motion to the canopy (parachute) motion are focused. A solid concave body is set in a vertical water tunnel which is driven by siphon’s low. Here, the uniform flow direction is opposed to the gravity direction in order to simulate the real parachute vertical drop. Four types of supporting system are applied to investigate the effects of the payload motion. There are differences about degree of freedom of payload between four type tests. The displacement of the object is measured by using CCD camera motion analyzer, and experimental data is processed by a short-time Fourier transform(STFT). Results are summarized as follows. The degree of freedom of payload affects on the concave body motion significantly. The oscillation pattern of the concave body changes by time, those are linear, arc, and circular motion.