A Numerical Simulation of Fog Dissipation Using Passive Burner Lines. Part I: Model Development and Comparison with Observations

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  • 1 Naval Environmental Prediction Research Facility, Monterey, CA 93940
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Abstract

A two-dimensional model is developed to simulate dissipation of fog using passive burner lines under either cross-wind or no-wind conditions. The vorticity model developed by Murray (1970) forms the basis for the development. Among the additions to the model are a stretched vertical grid, provision for an ambient wind field and variable eddy exchange coefficients.

The model is tested by comparing results to empirical temperature distribution data resulting from burner lines, located both outdoors and in a wind tunnel, positioned in a cross wind. Equally good comparisons are achieved by running the model at these two different physical scales. It is determined that the parameterization of the eddy coefficients most influences the resulting temperature profiles, and that a form in which deformation and buoyancy are summed gives the best results. A coefficient based solely on the deformation or vorticity gradients is found to be inadequate. Several additional experiments which utilize a soil heat flux parameterization support empirical estimates of a 5% heat loss to the soil.

Abstract

A two-dimensional model is developed to simulate dissipation of fog using passive burner lines under either cross-wind or no-wind conditions. The vorticity model developed by Murray (1970) forms the basis for the development. Among the additions to the model are a stretched vertical grid, provision for an ambient wind field and variable eddy exchange coefficients.

The model is tested by comparing results to empirical temperature distribution data resulting from burner lines, located both outdoors and in a wind tunnel, positioned in a cross wind. Equally good comparisons are achieved by running the model at these two different physical scales. It is determined that the parameterization of the eddy coefficients most influences the resulting temperature profiles, and that a form in which deformation and buoyancy are summed gives the best results. A coefficient based solely on the deformation or vorticity gradients is found to be inadequate. Several additional experiments which utilize a soil heat flux parameterization support empirical estimates of a 5% heat loss to the soil.

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