The formation of a thermocline in a water column, where shear-free turbulence is generated from both the surface and the bottom, and a stabilizing buoyancy flux is imposed on the surface, was studied using a numerical model with the aim of understanding the formation of a tidal front in the coastal area. The time evolutions of the distributions of density and turbulent kinetic energy calculated from the model shows that the emergence of a thermocline depends on the conditions determined by the buoyancy flux at the surface Q, the eddy diffusivities maintained at the bottom and at the surface Kb and Ks and the height of the water column H. The criterion for the formation of a thermocline was predicted as Rδ4 ~ constant for large δ (δ > 0.5), but the dependence on δ decreases as δ tends to 0, where [formula omitted] is the depth of a thermocline in the absence of bottom mixing. The depth of a thermocline was found to decrease as the bottom mixing increases for a given value of D0. The results were interpreted in comparison with previous studies.
Bibliographical noteFunding Information:
The computations were carried out in double precision on the VAX 8650 and CRAY x-MP/14se at Arizona State University.T he author wishes to thank Professor H. J. S. Fernando for his help. During the preparation of this paper, the author was supported by the Physical Oceanography of the Office of the Naval Research and the National Science Foundation of U.S.A.
All Science Journal Classification (ASJC) codes
- Computational Mechanics
- Astronomy and Astrophysics
- Mechanics of Materials
- Geochemistry and Petrology