Shear Rate

Shear rate is the speed of deformation in the shear mode (which is typical of fluids and can be represented as layers sliding one onto another). It is expressed (SI units) in reciprocal seconds [1/s], since it derives from radiant per second, with radiant being dimensionless (just a number). For Newtonian fluids, shear rate is directly proportional to flow rate (for a given channel geometry), and a simple relationship is used to calculate its maximum value at the wall of the channel. When the fluid is non-Newtonian (notably the case of all plastic melts), this relationship gives only a first approximation, which is called the apparent value of wall shear rate. The true wall shear rate can be estimated by applying the Rabinowitsch correction, and is higher than the apparent value.

Related Content

3400 Series - Affordable Testing Solutions

Instron 3400 Series Universal Testing Systems for Tensile, Compression, Bend, and other material property tests.

6800 Series Premier Testing Systems Brochure

Instron 6800 Series Universal Testing Systems provide unparalleled accuracy and reliability. Built on a patent-pending Operator Protect system architecture with an all-new Smart-Close Air Kit and Collision Mitigation features, the 6800 Series makes materials testing simpler, smarter, and safer than ever before.

Bluehill Universal Brochure

Bluehill Universal Software is built from the ground-up for touch interaction and an intuitive user experience. Discover simpler and smarter testing with features such as pre-loaded test methods, QuickTest in seconds, enhanced data exporting: and Instron Connect – a new feature that provides a direct communication link to Service. Users of previous versions of software such as Bluehill 2 and Bluehill 3 can easily upgrade to the newest version of Bluehill.