In this work, fluid-solid interactions are numerically investigated for flow around three equally/unequally spaced square cylinders using the lattice Boltzmann method. Two major trends of shear layers observed for equal gap spacings between cylinders: (i) without roll up (W), and (ii) with roll up (R). While for unequal gap spacings, four major trends of shear layers observed: (i) without roll up in both gaps (WW), (ii) without rollup in first gap and with roll up in second gap (WR), (iii) with roll up in first gap and without roll up in second gap (RW), and (iv) with roll up in both gaps (RR). g = 3 is found to be the critical equal spacing value. Also g = 1.5 is found to be suitable equal spacing in terms of minimum drag force. While the suitable unequal gap spacing combinations found in this study are (g₁, g₂) = (1.5, 0.5), (g₁, g₂) = (3, 0.5) and (g₁, g₂) = (5, 0.5). Results show that flow induced forces can be suppressed by suitable unequal gap spacing combinations.