Abstract
A short cylinder with its length to diameter ratio of 2 is tested in a low-speed wind tunnel. Three models are prepared, which differ in the positions of the rotational center, 0%, 5% and 10% oifthe geometrical center. The tested Reynolds numbers are in a range of 6.7×10^4〜1.3×10^5, which are lower than the critical ones for a two dimensional cylinder. The model is attached to the 3-DOF rotatable support which allows the model to rotate about pitch, yaw and roll axes. All the models not only exhibit flat-spin motions but also fluctuate about the pitch and yaw axes as well. The flow visualization is applied by the tufts over the cylindrical surfaces, and it is found that the three dimensional flow directing to the sides induces the asymmetry.
