In this paper, a low Reynolds number flow (Re = 100) around the semicircular cylinder of diameter D with and without splitter plate is numerically investigated using in-house developed flexible forcing IB—LBM scheme. The length of the splitter plate is systematically varied from 0.5D to 4.0D to investigate its effect on the flow structure and on the vortex-induced forces. The recirculation region behind the semicircular cylinder is increased with an increase in the length of the splitter plate, and as a consequence the base pressure is recovered, and the time-averaged drag coefficient is reduced. Complete suppression of the fluctuating lift coefficient and von Karman vortex shedding is noticed for a splitter plate of length 4.0D for which a maximum drag reduction of around 32% is found. The wake regime as a function of splitter plate length is thoroughly analysed.