The investigations presented in this book, primarily computational, pertain to rheology, transport and erosion of solid liquid two-phase flow system. For flow characteristics of solid liquid suspension, the knowledge of their rheological behavior is of considerable importance. The mixtures of suspensions vary widely. They may be stable, slow or rapidly settling types. The rapidly settling suspensions with which present work is related offer considerable difficulty in the determination of apparent viscosity due to quick phase separation. This book deals with a careful investigation on the effect of solids concentration, particle size, size distribution, surface characteristics and drag reducing agent on the apparent viscosity of the suspensions. In the present investigation, two solids namely coal and copper ore which are opposite in surface characteristics have been chosen. It is observed that the coarse size coal in water exhibit less apparent viscosity compared to fines where as copper ore behaves in a reverse way. It is also found that particle size distribution has a marked influence on apparent viscosity of suspension.