Hostname: page-component-8448b6f56d-qsmjn Total loading time: 0 Render date: 2024-04-23T22:48:49.139Z Has data issue: false hasContentIssue false

Turbulent thermal convection in a rotating stratified fluid

Published online by Cambridge University Press:  24 September 2002

M. A. LEVY
Affiliation:
Environmental Fluid Dynamics Program, Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287-9809, USA
H. J. S. FERNANDO
Affiliation:
Environmental Fluid Dynamics Program, Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287-9809, USA

Abstract

Turbulent convection induced by heating the bottom boundary of a horizontally homogeneous, linearly (temperature) stratified, rotating fluid layer is studied using a series of laboratory experiments. It is shown that the growth of the convective mixed layer is dynamically affected by background rotation (or Coriolis forces) when the parameter R = (h2Ω3/q0)2/3 exceeds a critical value of Rc ≈ 275. Here h is the depth of the convective layer, Ω is the rate of rotation, and q0 is the buoyancy flux at the bottom boundary. At larger R, the buoyancy gradient in the mixed layer appears to scale as (db/dz)ml = 2, where C ≈ 0.02. Conversely, when R < Rc, the buoyancy gradient is independent of Ω and approaches that of the non-rotating case. The entrainment velocity, ue, for R > Rc was found to be dependent on Ω according to E = [Ri(1 + 2/N2)]−1, where E is the entrainment coefficient based on the convective velocity w∗ = (q0h)1/3, E = ue/w∗, Ri is the Richardson number Ri = N2h2/w2∗, and N is the buoyancy frequency of the overlying stratified layer. The results indicate that entrainment in this case is dominated by non-penetrative convection, although the convective plumes can penetrate the interface in the form of lenticular protrusions.

Type
Research Article
Copyright
© 2002 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)