Point Source Diffusion Formulas Based on a Gaussian Distribution

Point Source Diffusion Formulas Based on a Gaussian Distribution 

The presumption of a Gaussian distribution for the mean concentration from a point source, although demonstrated only in the case of stationary, homogeneous turbulence, has been made widely and, in fact, is the basis for many of the atmospheric diffusion formulas in common use. Based on the developments of Section IV, we present in this section the Gaussian point source diffusion formulas that have been used for practical calculations. 

Mean Concentration c (t, y, z) from a Continuous Point Source in an Infinite Fluid in Stationary, 

The Gaussian concept can be extended beyond that already developed in Section IV. The general Gaussian probability density function for the position of a fluid particle released from a source located at (x y, z ) at time t can be expressed as (Lamb, 1980) 

Since measurements of u v ), u w ), etc., usually indicate that the magnitudes of these covariances are much smaller than the mean square velocity fluctuations (m ), etc., it is generally assumed that the off-diagonal elements of P are negligible. Also, we use the notation, al = ((,1), cr, = 

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V. Point Source Diffusion Formulas Based on a Gaussian Distribution. 233... 

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