The time required to empty the contents of the storage vessels is known as efflux time. This time is very important either for enhancement of productivity or under emergency situations and hence is of considerable interest in a variety of industries like pharmaceutical,chemical and food. When a liquid drains from a large tank ( where the flow is laminar) through an exit piping system ( when the flow is turbulent),drag increase is drastic. This drag can be reduced by use of polymers, surfactants and mixed solutions of surfactant and its counter ion. This book is a compilation of experimental work carried out by authors in the department of Chemical Engineering, MVGR College of Engineering.