The experimental investigation on wake dynamics of flow around a circular cylinder with the splitter plate

•The wake dynamics of flow around a circular cylinder with the splitter plate are investigated at Re=3.9×103 using PIV.•The short splitter plate affects significantly wake characteristics for L/D≤1.•The effects of L/D on the evolution of wake structures and the wake development are revealed.•The reasons for variations of Strouhal number (St) are given.•The splitter plate significantly reduces the vertical fluctuations to inhibit wake fluctuations. The wake dynamics of flow around a circular cylinder with the splitter plate are investigated using particle image velocimetry (PIV). The Reynolds number based on the cylinder diameter D is Re=3.9×103, and the ratio of the splitter plate length L on the cylinder diameter varies from L/D=0 to L/D=2.5. The wake characteristics and vortex dynamics are strongly dependent on L/D. There are main and secondary recirculation regions behind the cylinder, and the range of the recirculation region presents an obvious increase as L/D increases from 0 to 1 due to the elongations of the cylinder shear layers. Moreover, the maximum velocity defect and the wake width are increased with increasing L/D, and the short splitter plate has important influences on the wake characteristics for L/D≤1. Based on the vortex dynamics, the splitter plate length can be divided into three regions. (i) For 0≤L/D