Abstract
When wind velocity is a step function, the drag forces show overshoots exceeding the quasi-steady level with a short time interval. It is called overshoot phenomena. In this study, overshoot phenomena is investigated by wind tunnel experiments and analyses. By wind tunnel experiments, time history of drag forces on a 2-D cylindrical model is measured under suddenly changed wind velocity. The wind velocity in the working section is controlled by opening the shutter suddenly and 2-D rectangular cylinders and circular cylinder are used in wind tunnel experiments. So we tried to compare drag force with calculation model. Since inertia forces have strong effects on overshoot phenomena under sudden increase of wind velocity. Also, we focused on them in addition to vortex shedding.
