Turbulent entrainment at the density interface of a stable two-layer stratified fluid is studied in the laboratory, a constant surface stress being applied at the free surface. Conservation of mass requires that the overall Richardson number Ri = Dg δρ/ρ u * 2 is constant in each experiment, where D is the depth of the mixed layer, g δρ/ρ the buoyancy difference and u * the friction velocity. If the entrainment rate E = u e / u * is a function only of Ri , it is therefore constant in each experiment and can be measured with a greater accuracy than has previously been attained. The functional dependence of u e / u * on Ri is established over the range 30 < Ri < 1000; it is found not to follow any simple power law. The entrainment rates are considerably higher than those measured by Kato & Phillips (1969), for which the fluid below the mixed layer was linearly stratified. Such a condition allows internal gravity waves to be radiated downwards and the reduction in entrainment rate is consistent with that found by Linden (1975).
An experiment is described in which a constant stress is applied to the surface of an initially quiescent tank of fluid with a uniform density gradient. The development of the t...
A suspended‐sediment‐induced, stably stratified oceanic bottom boundary layer is examined with the Mellor‐Yamada level II turbulence closure model. The boundary layer equations ...
A one-dimensional higher order turbulence closure model is used to investigate moisture structure within the diurnally varying planetary boundary layer. The diurnal character of...
Turbulent mixing lengths and the eddy Prandtl number are estimated by analyzing aircraft data from three different field programs and existing studies in the literature. For sma...
AbstractA simple model is given that describes the response of the upper ocean to an imposed wind stress. The stress drives both mean and turbulent flow near the surface, which ...
Social media, news, blog, policy document mentions