Relating wind-induced gas transport in porous media to wind speed and medium characteristics

Impact of wind speed characteristics and porous medium properties on wind-induced gas dispersion in near surface porous media, was investigated using experimental data for four porous materials and 11 wind conditions. The data were used to evaluate two recent empirical models (involving 2 and 3 empirical parameters, respectively) for predicting wind-induced gas dispersion in porous media as a function of distance to the wind-exposed surface. Regression analyses were used to identify relationships between the empirical model parameters, wind speed characteristics (wind speed, wind turbulence index, wind speed power spectrum) and porous medium properties (particle diameter, porosity, hydraulic conductivity, tortuosity). While only one parameter in the three-parameter model correlated well with wind speed power spectrum characteristics and porous medium properties, both parameters in the two-parameter model correlated well with r² ranging up to 0.99 where r² is the regression coefficient. The strongest relationships were observed between model parameters and vertical wind speed, minimum particle diameter, particle surface roughness, saturated hydraulic conductivity and molecular gas diffusion coefficient with r² values generally on the order of 0.85–0.95. Overall, the results indicated that wind-induced gas dispersion porous media can be predicted based on wind speed characteristics and porous medium properties.