Measurement of yield stress of fluid‐like viscoplastic substances

Abstract

Abstract The concept of the yield stress of a fluid is discussed and the principle methods which have been used to evaluate it are critically reviewed. It is shown that many factors can influence the determination of this parameter. Most of the existing methods determine some property near an interface or wall rather than the actual yield stress value which is a physical property of the fluid itself. A procedure and technique for measuring the actual yield stress of a substance is suggested which seems to eliminate most of the shortcomings of other methods.