Abstract
In the present work, heat transfer and entropy generation characteristics are numerically investigated in presence of single and double obstructive blocks within a square enclosure. It is found that the adiabatic block(s) enhance(s) the heat transfer marginally up to a critical size in a convection-dominated regime. On the other hand, the enhancement parameter is observed to be more with an increase in block size in a lower range of Rayleigh numbers for an isothermal block. The entropy generation for thermal irreversibility is observed to be several orders higher than that due to viscous dissipation in all cases.