Processing and storage vessels in chemical industries are available in different shapes. The time required to drain these vessels is known as efflux time. Draining a liquid from a large storage vessel through an exit pipe is always associated with laminar flow in the tank and turbulent flow in the exit pipe depending on the physical properties of the liquid and the geometrical characteristics of the exit piping system. During draining, the liquid experiences friction and this friction is a measure of drag. The drag increases many fold when the flow transforms from laminar flow in the tank to turbulent flow in the exit pipe. Hence, drag reduction options are to be explored. The phenomenon of drag reduction by minute concentrations of polymer additives has been attempted for over sixty years, ever since its discovery by Toms. This book is focused on understanding drag reduction using water soluble polyacryl amide polymer solutions when a Newtonian liquid ( water in this case) is drained from a cylindrical storage vessel ( Where the flow is essentially laminar) through an exit piping system ( When the flow in the exit pipe is turbulent).