Abstract
Dimensionless shear functions, φm, φh and φw, have been obtained as a function of a dimen-sionless length, ξ, by following the method which leads to the KEYPS formula, but with adop-tion of the assumption that Kh/Km and Kw/Km respectively are a function of stability. The obtained formula for φm in stable conditions resulted in the KEYPS formula itself. As is well known it disagrees with observations, so that modification of it was attempted by means of dimensional analysis. Two modified forms have been derived. Comparison of the obtained formulae with observed results by other workers was then made. Finally criticism to the concept of the critical Richardson number was expressed.
