Eddy damping by surface active agents in interfacial turbulence

Abstract

In the present work, a study has been made of the nature of interfacial resistance to mass transfer caused by films of surface active substances at the liquid-liquid interface or liquid-gas interface in an agitated cell, since at a clean interface there is conclusive evidence that no resistance of any industrial consequences arises, but transport phenomena is markedly damped across interfaces with such films. The paper purports that the frequency damping of eddy penetration into the turbulent interface is not the decisive factor in the retardation of transport phenomena across film covered interfaces, but the area of clearance of film molecules by the penetrating eddy at the interface. The eddy is modeled as a lump of fluid which is impelled into the interface and disturbs the film's molecules over a “Prandtle mixing length” which retaliates by means of its elasticity, thereby resisting the clearance of each eddy. On this basis, a formula has been obtained for the amount of clearance of area, hence the amount of area renewal, and the damping of transport phenomena which incorporates the surface compressional modulus of elasticity.