An experiment on boundary mixing. Part 2 The slope dependence at small angles

Experiments of the type described by Phillips et al. (1986) were performed using different slopes with the aim of examining the slope dependence of the buoyancy and volume transports, particularly at small slopes. The new observations confirmed the general flow patterns described for experiments conducted at a fixed slope, but a reconsideration of the local balances suggest that the buoyancy flux at small slopes θ is proportional to $(\kappa N)^{\frac{3}{2}}\sin\theta $, where κ is the turbulent diffusivity. and the volume flux associated with the overall convergence flow is linear with depth and proportional to (κ^3/2/N^½h) sin θ, where h is the thickness of the pycnocline. These differ in their dependence on the slope suggested (but not tested) in Phillips et al., and are generally consistent with measurements over a range of slopes from 7.1° to 23.5°.