Abstract: The flow around a cantilevered circular cylinder with an aspect ratio of 2 in a smooth laminar flow and a uniform turbulent flow (I_u=9.5%) is studied experimentally to investigate the aerodynamic forces, including drag coefficients, mean pressure distributions and fluctuating pressure distributions, in the flow from the subcritical to supercritical regime with a high turbulence intensity. The freestream velocity ranges from 5~20m/s, corresponding to Reynolds numbers in the range of 1.73×10⁵ to 6.90×10⁵. The results in the smooth laminar flow indicate that:(1) in the critical regime, the step-like drop of the mean drag coefficient grows larger with the increase of aspect ratios; in the supercritical regime, the mean drag coefficient decreases with the increase of aspect ratios; in the subcritical regime, the peak values of the fluctuating pressure locates at the angle of 70° and moves backward to 110°~115° in the supercritical regime. Sharp peaks occur in the fluctuating pressure distributions at supercritical Reynolds numbers. (2) the results in the uniform turbulent flow show that the peak values of fluctuating pressure occur at the same angles as those in the smooth laminar flow at supercritical Reynolds numbers and change little with the change of Reynolds numbers.