Drag and flow-induced sound reduction on a circular cylinder fitted with splitter plate is numerically studied. The numerical simulations of the cylinder, without and with splitter plate, have been carried out at subcritical Reynolds number (Re) of 97,300 using large eddy simulation (LES). Ffowcs Williams and Hawkings (FW-H) acoustic analogy has been used to calculate the sound field. The length of the splitter plate (H) varies from 0.5D to 3D, where D is the cylinder diameter in simulations. It is shown that both drag and sound levels decrease with increasing H initially and then increase with increasing H. However, the values of H beyond which the drag and sound levels starts increasing with further increase in H are different. This provides a multi-objective optimization problem, which has been studied in this paper using the particle swarm optimization method. © 2017