Since pump is used to transport liquid phase, any fluid feeds shall be maintained at above pour point and lower than the saturation temperature (as a function of saturation pressure); avoid vapor lock. For fluid mechanics, the nature of the pipe flow is strongly dependent on whether the flow is laminar or turbulent (specified by Reynolds number, Re=ρVD/μ) which is a direct consequence of the differences in the nature of the shear stress in those two regions. The physical properties of shear stress are different from laminar flow than for turbulent flow. Water is not a very viscous fluid.