Energy conservation and management is the need of the present hour.Protrusions like Blocks, Partitions and Fins are considered as retarders during convection and consume more energy. This book deals the physics about laminar natural convection inside the ventilated enclosure with twin adiabatic blocks. A finite difference based two - dimensional Numerical analysis has been performed using Streamfunction - Vorticity approach.The twin solid blocks are initially placed across the flow path and then shifted away from the flow path.To make it interesting as well as comfortable for readers, the physics is elucidated with wide number of figures through streamlines, isotherms, pressure drop and Nusselt number. The ultimate aim of this book is to guide the enthusiastic student and research community during the process of learning so that they can achieve success without any difficulty. The book is written considering the wider section of readers with great emphasis given to the basics. This book shall provide an ideal platform for the enthusiastic researchers during their comprehensive research on natural convection.