slug/foot/second Unit Converter

Definition of slug/foot/second unit

The slug per foot per second (slug/(ft·s)) is a British engineering unit of dynamic viscosity. It measures resistance to shear: one unit produces one pound-force per square foot of shear stress when the velocity gradient is one reciprocal second.

History of slug/foot/second unit

The unit arose from the British gravitational system, which treated the slug as the mass that accelerates at one foot per second squared under one pound-force. Engineers consequently expressed dynamic viscosity as mass divided by length and time, yielding slug per foot per second. It is the coherent U.S. customary counterpart of the SI pascal-second, although pound-force-based viscosity units, especially pound-force-second per square foot, have often appeared in practice. The slug-based form remains important in fluid-mechanics references and dimensional analysis, reflecting nineteenth- and twentieth-century development of engineering unit systems.

Applications of slug/foot/second unit

Today, slug/(ft·s) is used mainly in aerospace, automotive, mechanical, and chemical-engineering calculations involving air, oils, fuels, and other fluids in U.S. customary units. Engineers may use it in Navier–Stokes equations, Reynolds-number evaluations, and computational models. For practical reporting, values are frequently converted to pound-force-second per square foot or pascal-seconds.

Complete list of slug/foot/second unit conversion