A note on the mass flux for rapidly rotating recycling flow over topography

Abstract

This paper reports some measurements of the circumferential mass flux in a rotating cylindrical annulus spanned by a transverse ridge and containing a homogeneous liquid. Flows are driven by a differentially rotating lid in the shape of a parabola so as to simulate a polar β-plane. Unless the Rossby number R₀ = ω/2Ω, based on the lid rotation rate ? and the basic rotation rate Ω, is quite small the mass flux is less for the β-plane than for f-plane (flat lid) geometry. The mass flux is reduced in the β-plane case by mountain wave drag associated with the formation of Rossby waves in the annulus downstream of the topography. When R02 is less than the Ekman number the β-plane mass flux exceeds that of the f-plane case. Streak photographs demonstrate the qualitative nature of the flow.