The numerical simulations of this paper present the flow structure of an isothermal cylinder with curved corners r/R = 0.5, where R is the half-width and r is the corner radius of the cylinder, with the varied angle of attack, α (0° ≤ α ≤ 45°). The cylinder is located perpendicular to the air stream flow with Re = 180 and Pr = 0.7. The solution of the governing equations obtained using ANSYS-FLUENT package. The variation of α from 0° to 45°, leads to two major flow regimes A and B. The flow regime of type A appears at a small range of α (0° ≤ α < 10°), can be termed as trailing corner separated flow. The flow regime of type B appears within the large range of α (10° ≤ α ≤ 45°), can be termed as leading-trailing corner separated flow. The flow structure is unsteady and characteristic by alternating Kármán vortices appears for each α. The maximum vorticity |w_z^* |max is inversely linked to the wake bubble length L_b^*. The lower core (positive) instantaneous vorticity increases with increasing α with slight increasing for α = 0° - 5° and 30° - 45°, while large increasing for α = 5° - 30°.