Buoyancy induced dispersion

Buoyancy-induced dispersion, which is caused near the source due to the rapid expansion of the plume during the rapid rise of the thermally buoyant plume after its release from the point of discharge, should also be included for buoyant releases (15). The effective vertical dispersion cr is found from... 

Since in the initial growth phases of a buoyant plume the plume is nearly symmetrical about its centerline, the buoyancy-induced dispersion in the crosswind (horizontal) direction is assumed to be equal to that in the vertical. Thus, the effective horizontal dispersion is found from... 

At a downwind distance of 800 m from a 75-m source having an 180-m plume rise, cr, is estimated as 84 m and cr is estimated as 50 m. If one considers buoyancy-induced dispersion as suggested by PasquUl, by how much is the plume centerline concentration reduced at this distance ... 

The values of u and A0/AZ are based on assumed conditions of stability class F and stack height wind speed of 2.5 m/s for the stable layer above the inversion. The value of hj incorporates the effect of buoyancy induced dispersion on a/, however, elevated terrain effects are igndred. The equation above is solved by iteration, starting from an initial guess of x , = 5,000 m. The maximum ground-level concentration due to inversion break-up fumigation, Xf, is calculated from ... 

Plume height is based on the assumed F stability and 2.5 m/s wind speed, and the dispersion parameter (o, ) incorporates the effects of buoyancy induced dispersion. If x , is less than 200 m, then no shoreline fumigation calculation is made, since the plume may still be influenced by transitional rise and its interaction with the TIBL is more difficult to model. 

Shape oscillation and translational motion of gas bubbles inside a liquid medium is also achieved in the context of forced vibration of hquid containers with dispersed gas bubbles. Vibration induces an acceleration and effectively a buoyancy force which oscillates in time. Depending on the direction of the applied force, bubbles move in the liquid medium, and since the pressure variation around the bubble is... 

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