The design of hydraulic machinery in general, and of centrifugal pumps in particular, has been, and still is, essentially empirical. One reason for this is the great variety of types, sizes, and uses of centrifugal pumps, resulting in a great multiplicity of design considerations.

Iver Brynild Neumann is a Norwegian political scientist and social anthropologist. He is the current Montague Burton Professor of International Relations at the London School of Economics and Political Science.