Abstract
A series of experiments has been performed for a linearly salt-stratified system heated from below. The experiments were intended to investigate the relative influence of external and double-diffusive convection on (i) entrainment of salt-stratified fluid into adjacent layers of convecting fluid, and (ii) formation of multiple mixed layers within stable, salt-stratified fluid layers. External convection effects were altered by placing a horizontal grid in the convecting fluid layer. An assortment of flow visualization techniques revealed that external convection can strongly influence entrainment of salt-stratified fluid and multiple mixed layer formation. However, the techniques could not resolve the possible significance of the double-diffusive entrainment mechanism.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- g :
-
gravitational acceleration
- H :
-
mixed layer height
- H m :
-
grid height
- k :
-
thermal conductivity
- m s :
-
salt mass fraction
- q b :
-
bottom heat flux
- Ra Emphasis>/* T :
-
modified thermal Rayleigh number, g β T q b H 4/κ α ν
- Ra s :
-
solutal Rayleigh number, g β s (∂m s/∂ z ) i H 4/α ν
- Ri :
-
Richardson number
- T :
-
temperature
- X :
-
stability parameter, Ra *T /Ra s
- z:
-
vertical coordinate
- α:
-
thermal diffusivity
- βs :
-
saline expansion coefficient
- β T :
-
thermal expansion coefficient
- δ:
-
interface height in two layer system
- ν:
-
kinematic viscosity
- i :
-
initial
References
Bergman, T. L.; Incropera, F. P.; Viskanta, R. 1985: A differential model for salt-stratified, double-diffusive systems heated from below. Int. J. Heat Mass Transfer 28, 779–788
Bergman, T. L.; Incropera, F. P.; Viskanta, R. 1986: Correlation of mixed layer growth in a double-diffusive, salt-stratified system heated from below. J. Heat Transfer 108, 206–211
Crapper, P. F. 1975: Measurements across a diffusive interface. Deep Sea Res. 22, 537–545
Deardorff, J. W.; Willis, G. E.; Stockman, B. H. 1980: Laboratory studies of the entrainment zone of a convectively mixed layer. J. Fluid Mech. 100, 41–64
Huppert, H. E.; Linden, P. F. 1979: On heating a stable salinity gradient from below. J. Fluid Mech. 95, 431–464
Kantha, L. H.; Phillips, O. M.; Azad, R. S. 1977: On turbulent entrainment at a stable density interface. J. Fluid Mech. 79, 753–768
Kantha, L. H. 1980: A note on the effect of viscosity on double-diffusive processes. J. Geophys. Res. 85, 4398–4404
Linden, P. F. 1973: The interaction of a vortex ring with a sharp density interface: a model for turbulent entrainment. J. Fluid Mech. 60, 467–480
Linden, P. F. 1975: The deepening of a mixed layer in a stratified fluid. J. Fluid Mech. 71, 385–405
Linden, P. F.; Shirtcliffe, T. G. L. 1978: The diffusive interface in double-diffusive convection. J. Fluid Mech. 87, 417–432
Meyer, K A.; Grimmer, D. P.; Jones, G. F. 1982: An experimental and theoretical study of salt-gradient pond interface behavior. In: Progress in Solar Energy, pp. 185–190. American Section of the International Solar Energy Society
Meyer, K. A. 1983: A numerical model to describe the layer behavior in salt-gradient solar ponds. J. Sol. Energy Eng. 105, 341–347
Poplawsky, C. J.; Incropera, F. P.; Viskanta, R. 1981: Mixed layer development in a double-diffusive, thermohaline system. J. Sol. Energy Eng. 103, 351–359
Tabor, H. 1981: Solar ponds. Sol. Energy 27, 181–194
Turner, J. S. 1968: The behavior of a stable salinity gradient heated from below. J. Fluid Mech. 33, 183–200
Turner, J. S. 1979: Buoyancy effects in fluids. London: Cambridge University Press
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bergman, T.L., Incropera, F.P. & Viskanta, R. Interaction of external and double-diffusive convection in linearly salt-stratified systems. Experiments in Fluids 5, 49–58 (1986). https://doi.org/10.1007/BF00272425
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00272425