• Beets, C., M. J. Molemaker, and J. Vilà-Guerau de Arellano, 1996: Direct numerical simulation and large-eddy simulation of a non-premixed binary reaction in a turbulent convective boundary layer. Engineering Turbulence Modeling and Measurements, W. Rodi and G. Bergeles, Eds., Elsevier, Vol. 3, 279–282.

  • Bilger, R. W., 1980: Turbulent flows with nonpremixed reactants. Turbulent Reacting Flows, P. A. Libby and F. A. Willimas, Eds., Springer-Verlag, 243 pp.

  • Chatfield, R. B., and R. A. Brost, 1987: A two-stream model of the vertical transport of trace species in the convective boundary layer. J. Geophys. Res.,92, 13262–13276.

  • Colenman, G. N., J. H. Ferziger, and P. R. Spalart, 1990: A numerical model of the turbulent Ekman layer. J. Fluid Mech.,213, 313–348.

  • Danckwerts, P. V., 1952: The definition and measurement of some characteristics of mixtures. Appl. Sci. Res.,18A, 25–60.

  • Deardorff, J. W., 1972: Numerical investigation of neutral and unstable planetary boundary layer. J. Atmos. Sci.,29, 91–115.

  • ——, and G. E. Willis, 1967: Investigation of turbulent thermal convection between horizontal plates. J. Fluid Mech.,28, 675–704.

  • Dennis, R. L., D. W. Byun, J. H. Novak, K. J. Gallupi, C. J. Coats, and M. A. Vouk, 1996: The next generation of integrated air quality modeling: EPA’s models-3. Atmos. Environ.,30, 1925–1938.

  • Donaldson, C. du P., and G. R. Hilst, 1972: Effect of inhomogeneous mixing on atmospheric photochemical reactions. Environ. Sci. Technol.,6, 812–816.

  • Galperin, B., and S. A. Orszag, 1993: Large-Eddy Simulation of Complex Engineering and Geophysical Flows. Cambridge University Press, 600 pp.

  • Gao, W., and M. L. Wesley, 1994: Numerical modeling of the turbulent fluxes of chemically reactive trace gases in the atmospheric boundary layer. J. Appl. Meteor.,33, 835–847.

  • Grotzbach, G., 1982: Direct numerical simulation of laminar and turbulent Benard convection. J. Fluid Mech.,35, 27–53.

  • ——, 1983: Spatial resolution requirements for direct numerical simulation of the Rayleigh–Benard convection. Comp. Phys.,49, 241–264.

  • Herring, J. K., and J. C. Wyngaard, 1987: Convection with a first-order chemically reactive passive scalar. Turbulent Shear Flows, Vol. 5, Springer-Verlag, 324–336.

  • Lenschow, A. A., and A. A. Stephans, 1980: The role of thermals in the convective boundary layer. Bound.-Layer Meteor.,19, 509–532.

  • Libby, P. A., and F. A. Willimas, 1980: Turbulent Reacting Flows. Springer-Verlag, 243 pp.

  • Moeng, C.-H., 1984: A large-eddy-simulation model for the study of planetary boundary layer turbulence. J. Atmos. Sci.,41, 2052–2062.

  • ——, and J. C. Wyngaard, 1984: Statistics of conservative scalars in the convective boundary layer. J. Atmos. Sci.,41, 3161–3169.

  • ——, and R. Rotunno, 1990: Vertical-velocity skewness in the buoyancy-driven boundary layer. J. Atmos. Sci.,47, 1149–1162.

  • Piper, M., J. C. Wyngaard, W. H. Snyder, and R. E. Lawson Jr., 1995:Top-down, bottom-up diffusion experiments in a water convection tank. J. Atmos. Sci.,52, 3607–3619.

  • Randall, D. A., Q. Shao, and C. H. Moeng, 1992: A second-order bulk model. J. Atmos. Sci.,49, 1903–1923.

  • Riley, J. J., R. W. Metcalfe, and S. A. Orszag, 1986: Direct numerical simulation of chemically reacting turbulent mixing layers. Phys. Fluids,29, 406–422.

  • Schumann, U., 1989: Large-eddy simulation of turbulent diffusion with chemical reactions in the convective boundary layer. Atmos. Environ.,23, 1713–1727.

  • ——, 1993: Transport asymmetry in skewed convective circulations. J. Atmos. Sci.,50, 116–119.

  • Seinfeld, J. H., 1986: Atmospheric Chemistry and Physics of Air Pollution. John Wiley and Sons, 738 pp.

  • Stockwell, W. R., 1995: Effects of turbulence on gas-phase atmospheric chemistry: Calculation of the relationship between time scales for diffusion and chemical reaction. Meteor. Atmos. Phys.,57, 159–171.

  • Sykes, R. I., F. Parker, D. S. Henn, and W. S. Llewellen, 1994: Turbulent mixing with chemical reaction in the planetary boundary layer. J. Appl. Meteor.,33, 825–834.

  • Tennekes, H., and P. Lumley, 1973: A First Course in Turbulence. The MIT Press, 300 pp.

  • Vilà-Guerau de Arellano, J., P. G. Duynkerke, and K. F. Zeller, 1995:Atmospheric surface layer similarity theory applied to chemically reactive species. J. Geophys. Res.,100, 1397–1408.

  • Wyngaard, J. C., and R. A. Brost, 1984: Top-down and bottom-up diffusion of a scalar in the convective boundary layer. J. Atmos. Sci.,41, 102–112.

  • ——, and J. C. Weil, 1991: Transport asymmetry in skewed turbulence. Phys. Fluids,A3, 155–162.

  • ——, W. T. Pennell, D. H. Lenschow, and M. A. LeMone, 1978: The temperature-humidity covariance budget in the convective boundary layer. J. Atmos. Sci.,35, 47–58.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 141 141 10
PDF Downloads 38 38 9

Control of Chemical Reactions by Convective Turbulence in the Boundary Layer

View More View Less
  • 1 Institute for Marine and Atmospheric Research, University of Utrecht, Utrecht, the Netherlands
  • | 2 Departament Fisica Aplicada, Universitat Politècnica de Catalunya, Barcelona, Spain
© Get Permissions
Restricted access

Abstract

The influence of convective turbulence on chemical reactions in the atmospheric boundary layer is studied by means of direct numerical simulation (DNS). An archetype of turbulent reacting flows is used to study the reaction zones and to obtain a description of the turbulent control of chemical reactions. Several simulations are carried out and classified using a turbulent Damköhler number and a Kolmogorov Damköhler number. Using a classification based on these numbers, it is shown that it is possible to represent and to solve adequately all relevant scales of turbulence and chemistry by means of DNS. The simulations show clearly that the reaction zones are located near the boundaries where the species are introduced. At the lower boundary of the convective boundary layer, the reaction takes place predominantly in the core of the updrafts, whereas in the upper part of the domain the chemical reaction is greatest in the center of the downdrafts. In the bulk of the boundary layer the chemical reaction proceeds very slowly, due to the almost complete segregation of the chemical species. From the point of view of chemistry, the mixing across the interface between updrafts and downdrafts in the bulk of the convective boundary layer plays only a minor role.

The amount of chemical reaction in relation to the degree of turbulence is quantified by the introduction of an effective Damköhler number. This dimensionless number explicitly takes into account the reduction of the reaction rate due to the segregation of the chemical species. It is shown that the number approaches an asymptotic value that is O(1) for increasingly fast reaction rates. This shows explicitly that the timescale of the chemical reactions is limited by the integral turbulent timescale. It is suggested how a parameterization could be used to include this effect into one-dimensional atmospheric models.

Corresponding author address: Dr. M. Jeroen Molemaker, Institute for Marine and Atmospheric Research, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, the Netherlands.

Email: nmolem@fys.ruu.nl

Abstract

The influence of convective turbulence on chemical reactions in the atmospheric boundary layer is studied by means of direct numerical simulation (DNS). An archetype of turbulent reacting flows is used to study the reaction zones and to obtain a description of the turbulent control of chemical reactions. Several simulations are carried out and classified using a turbulent Damköhler number and a Kolmogorov Damköhler number. Using a classification based on these numbers, it is shown that it is possible to represent and to solve adequately all relevant scales of turbulence and chemistry by means of DNS. The simulations show clearly that the reaction zones are located near the boundaries where the species are introduced. At the lower boundary of the convective boundary layer, the reaction takes place predominantly in the core of the updrafts, whereas in the upper part of the domain the chemical reaction is greatest in the center of the downdrafts. In the bulk of the boundary layer the chemical reaction proceeds very slowly, due to the almost complete segregation of the chemical species. From the point of view of chemistry, the mixing across the interface between updrafts and downdrafts in the bulk of the convective boundary layer plays only a minor role.

The amount of chemical reaction in relation to the degree of turbulence is quantified by the introduction of an effective Damköhler number. This dimensionless number explicitly takes into account the reduction of the reaction rate due to the segregation of the chemical species. It is shown that the number approaches an asymptotic value that is O(1) for increasingly fast reaction rates. This shows explicitly that the timescale of the chemical reactions is limited by the integral turbulent timescale. It is suggested how a parameterization could be used to include this effect into one-dimensional atmospheric models.

Corresponding author address: Dr. M. Jeroen Molemaker, Institute for Marine and Atmospheric Research, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, the Netherlands.

Email: nmolem@fys.ruu.nl

Save