On the Reverse Effectiveness and the Time-Lag of a Spoiler

Abstract

An experimental study is performed on the transient response of a split-type spoiler in twodimensional flow. The results indicate that the time-lag and the magnitude of reverse effectiveness of a spoiler are influenced not only by the chord-wise location of the spoiler but also by the ratio of the actuation time of it to the characteristic time of the flow (e.g. chord length devided by the flow velocity). A physical explanation of the phenomena is presented and a method to predict the above mentioned quantities is proposed.