This study investigates the aeroacoustics of flow around a square cylinder using an in-house OpenFoam solver with Ffowcs Williams’ Hawking methodology and the [Formula: see text] SST turbulence model. First, the numerical results were validated against experimental data. Then, the effects of a 1[Formula: see text]mm thick splitter with different lengths, 2.5 ([Formula: see text]), 5 ([Formula: see text]), 7.5 ([Formula: see text]) and 10 ([Formula: see text]), were studied as a passive control method. The findings indicate that the splitter suppresses the vortex shedding, a dipole source of aeroacoustic emission, resulting in a reduction of the noise level by up to 7% for [Formula: see text] for [Formula: see text] for [Formula: see text] and 17.5% for [Formula: see text].