Experimental Study on Directional Stability of Tumbling Plate

Abstract

This paper describes the directional stability of the tumbling plate by measuring the trajectory of a paper piece that is shaped systematically. The tumbling phenomenon is considered to be an important phenomenon for aircraft flight safety because of the possibility of falling objects from the aircraft reaching far away. Therefore, this paper presents the result of measuring the trajectory of six configurations which shows that Concave configurations have directional stability while the Convex and Rectangular configurations are unstable. For generalization, the experimental result deducted using generalized equations into dimensionless values. Qualitative consideration is given to the relationship between the stall delay caused by sudden pitch motion and the phenomenon of the increase in the maximum vertical force coefficient (so-called Dynamic Lift), and the consistency with the dynamic lift wind tunnel test is shown.

Proposal of a method to measure aerodynamic forces without using force sensors in wind tunnel testing of tumbling plates

“…The authors have proposed the relation between the lift force of the tumbling plate and the so-called dynamic lift in [11]. The decrease of rotational speed decreases lift generated by dynamic lift.…”

Parametric Study for Directional Stability of Tumbling Plates by Wind Tunnel Testing

“…The authors have pointed out that the directional stability changes depending on the configuration of the tumbling plate by the free fall test [9]. The purpose of this study is to consider the stable conditions from the viewpoint of the force measured by the wind tunnel test.…”

“…Test apparatus is shown in Fig. 3, which is same as [9]. The trajectory of falling model is acquired by using stereoscopic technique same as written in 4.4.…”

“…This is because when the falling object starts to turn, the area to reach is limited to the vicinity of the position where the falling object started to fall. Authors have focused on this directional stability of the tumbling plate and studied the directional stability for typical configurations [9]. Also, authors have proposed a new towing wind tunnel test method of the tumbling plate [12].…”

“…Therefore, many tests to measure the force act on the tumbling plate in wind tunnel have been conducted. The authors have been studying the directional stability of the tumbling plate [9], which has a great effect on the reach of falling objects, and have proposed a non-contact measurement method wind tunnel test method from the viewpoint of dynamic balance which can acquire the force without force sensors [12]. Here, we call "towing wind tunnel test method".…”