LAUSR

Mixed convection in a lid-driven square cavity with different walls temperature in the existence of four rotating cylinders having harmonic motion is simulated numerically for various parameters such as the solid volume fraction (0 ≤  ϕ  ≤ 0.03), Richardson number (0.1 ≤ Ri ≤ 10) and type of motion for each cylinder. Cu–water nanofluids are considered as fluid inside the enclosure. A comparison of full rotation and harmonic rotation in steady and transient cases was made to get a better understanding of the effect of harmonic rotation. The consequences of this study are obtainable in terms of average and local Nusselt numbers, isotherm contours, streamlines contours, velocity profiles, PEC, and entropy generation profiles. Obtained results show that the heat transfer is dependent on the angular velocity of the cylinder, type of rotation, and the nanoparticle concentration. Adding nanoparticles causes to improve the heat transfer rate. However, the effect of the nanofluids on geometry has decreased for the PEC, except for Ri = 1 and a few particular cases. Also, according to the Nusselt number graphs, we can tell that the harmonic motion in this study did not have a considerable effect on the heat transfer rate.