The Overshoot Coefficients of Unsteady Drag Exerted on the Square Cylinder by Gust Wind

Abstract

The overshoot phenomenon of unsteady drag exerted on a square cylinder by gust wind is revised from the viewpoint of the non-dimensional rise time of the wind history. The overshoot coefficient which is the ratio of the maximum drag to the steady drag is obtained through wind tunnel experiment and numerical flow analysis. It is also shown that the overshoot phenomenon is well described by means of the Morison formula. A formula to predict the overshoot coefficient as a function of the non-dimensional rise time is derived. The formula is well predicting the overshoot coefficients of the referred experiment and numerical analysis.