Interfacial Resistance in Stratified Flows

Abstract

The interfacial friction coefficients in a two‐layered stratified flow have been studied in a closed 15 m long rectangular duct with fresh water flowing over a quasi‐stagnant salt water pool. A one‐dimensional flow model along Schijf‐Schoenfeld's line for open channels was developed and used. The average interfacial friction coefficient was found to be best correlated with the number RF2, in which R and F are the Reynolds and Froude numbers respectively, and with the relative density difference Δρ/ρ used as an independent parameter. There is dose agreement with re‐analyzed data from an earlier study while one data point from the Mississippi estuary falls on a smooth extrapolation of the appropriate curve. The interfacial friction coefficient cannot be uniquely correlated with either the Reynolds number or the Froude number or the Keulegan number. This is in agreement with the results of a literature review on the subject.