Friction 4 : The resistance to a object's passage through a fluid (or a fluid's passage past a stationary object). Affected by viscous resistance, density, wall contact (vessel radii)
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}