Abstract
Convection between horizontal, stress-free, perfectly conducting plates is examined in the turbulent regime for air. Results are presented for an additional scalar undergoing first order decay. We discuss qualitative aspects of the flow in terms of spectral and three-dimensional isosurface maps of the velocity and scalar fields. The horizontal mean profiles of scalar gradients and fluxes agree rather well with simple mixing-length concepts. Further, the mean profiles for a range of the destruction-rate parameter are shown to be nearly completely characterized by the boundary fluxes. Finally, we use the present numerical data as a basis for exploring a generalization of eddy-diffusion concepts that incorporates necessary non-local effects.
The National Center for Atmospheric Research is sponsored by the National Science Foundation
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
Abbreviations
- C(x,y,z,t)):
-
Concentration of decaying scalar
- 〈C〉):
-
Horizontal (or ensemble) average of C = 〈C〉 (z, t)
- [C]):
-
Volume average (over periodic domain) of C
- D):
-
Depth of convective layer
- E υ ):
-
Kinetic energy spectrum
- g):
-
Acceleration of gravity
- ĝ):
-
Unit vector along g
- k):
-
Wave number vector
- k0):
-
Lowest k in numerical simulation
- Nu):
-
Heat flux through lower plate in units kΔT/D
- Nc(0)):
-
Scalar flux through lower boundary; units are same as for Nu
- Nc(1)):
-
Scalar flux through top plate; units are same as for Nu
- p):
-
Pressure field
- r):
-
Position vector
- Ra):
-
Rayleigh number gα(T(0) — T(1))/(κνD 3 )
- Rc):
-
Critical Ra for slip boundaries 27 π4/4
- Rλ):
-
Taylor microscale Reynolds number = 〈w 2〉/〈(∂w/∂z)2〉½ν
- T(x, y, z, t)):
-
Temperature
- 〈T〉):
-
Horizontal (or ensemble average) of T= 〈T〉 (z, t)
- T(0)):
-
Lower plate temperature
- T(1)):
-
Top plate temperature
- u (x, y, z, t)):
-
Velocity field (x, y, z)
- u(x, y, z, t)):
-
x-component of velocity field
- v(x, y, z, t)):
-
y-component of velocity field
- w(x,y,z,t)):
-
z-component of velocity field
- α):
-
Thermal expansivity
- β):
-
Horizontal average of — ∂T/∂z
- β):
-
C Horizontal average of — ∂C/∂z
- γ):
-
Ratio of diffusivities for C and T, respectively
- ΔT):
-
Temperature excess of lower plate over upper plate
- Z):
-
Reacting scalar variance spectrum
- ζ):
-
Fluctuation of C from its horizontal average
- ε):
-
Fractional destruction rate of C in units of the thermal diffusion time
- κ):
-
Thermometric diffusivity
- κ c ):
-
Diffusivity for scalar C
- ν):
-
Kinematic viscosity
- φ 1):
-
Toroidal velocity variance; see (6 a)
- Sw):
-
Velocity derivative skewness [(∂w/∂z)3]/[(∂w/∂z)2]3/2
- ST,C):
-
Scalar mixed skewness [(∂A/∂z)2 (∂w/∂z)]/[(∂A/∂z)2] [(∂w/∂z)2]½, A = (C, T)
- (x, y, z)):
-
Cartesian components of r
- t):
-
Time
- φ 2):
-
Poloidal velocity variance; see (6 b)
- σ):
-
Prandtl number (ν/ κ)
- θ):
-
Fluctuation of T from its horizontal average
- Θ):
-
Temperature variance spectrum
- ω):
-
Vorticity ∇ × u
References
Lipps, F. B. (1976): Numerical simulation of three-dimensional Bénard convection in air. J. Fluid Mech. 75, 113–148
Curry, J. H., Herring, J. R., Orszag, S. Z., Loncaric, J. (1984): Order and disorder in two- and three-dimensional turbulence. J. Fluid Mech. 147, 1–38
Wyngaard, J. C., Brost, R. A. (1984): Top-down and bottom-up diffusion of a scalar in the convective boundary layer. J. Atmos. Sci. 41, 102–112
Kraichnan, R. H. (1962): Turbulent thermal convection at arbitrary Prandtl number. Phys. Fluids 5, 1274–1389
Fiedler, B. E. (1984): An integral closure model for the vertical turbulent flux of a scalar in a mixed layer. J. Atmos. Sci. 41, 674–680
Zippelius, A., Siggia, E. D. (1982): Disappearance of stable convection between free-slip boundaries. Phys. Rev. A26, 1788–1790
Herring, J. R., Jackson, S. (1984): “Thermal Convection: Numerical Experiments near the Onset to Turbulence and the Statistical Theory of Turbulence,” in Turbulence and Chaotic Phenomena in Fluids, ed. by T. Tatsumi (Elsevier, Amsterdam) 111–116
Priestley, C. H. B. (1959): Turbulent Transfer in the Lower Atmosphere (Chicago University Press, Chicago)
Corrsin, S. (1961): Reactant concentration spectrum in turbulent mixing with a first-order reaction. J. Fluid Mech. 11/3, 407–416
Herring, J. R., Schertzer, D., Lesieur, M., Newman, G. R., Chollet, J. P., Larcheveque, M. (1982): A comparative assessment of spectral closures as applied to passive scalar diffusion. J. Fluid Mech. 42, 411–437
Moore, D. R., Weiss, N. O. (1972): Two dimensional Rayleigh-Bénard convection. J. Fluid Mech. 58, 289–312
Herring, J. R. (1963): Investigation of problems in thermal convection. J. Atmos. Sci. 20, 325–338
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1987 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Herring, J.R., Wyngaard, J.C. (1987). Convection with a First-Order Chemically Reactive Passive Scalar. In: Durst, F., Launder, B.E., Lumley, J.L., Schmidt, F.W., Whitelaw, J.H. (eds) Turbulent Shear Flows 5. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-71435-1_27
Download citation
DOI: https://doi.org/10.1007/978-3-642-71435-1_27
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-71437-5
Online ISBN: 978-3-642-71435-1
eBook Packages: Springer Book Archive