CANARINA:   DISPER:   SOLUTIONS: DISPER     COMMANDS:   ALGORITHMS:   EMISSIONS:   GRAPHS: Plume Rise Formulas The plume height is used in the calculation of the Vertical Term. The distance dependent momentum plume rise equations are used to determine if the plume is affected by the wake region for building downwash calculations.  Stack-tip Downwash In order to consider stack-tip downwash, modification of the physical stack height is performed. The modified physical stack height hs is found from: hs’=hs+2ds[(vs/us)-1.5]   for  vs<1.5us      (5) or hs’=hs                   for vs> o =1.5us   (6) where hs is physical stack height (m), vs is stack gas exit velocity (m/s), and ds is stack top diameter (m). If stack tip downwash is not considered, hs’= hs in the following equations. Buoyancy and Momentum Fluxes For most plume rise situations, the value of the Briggs buoyancy flux parameter, Fb (m4/s3), is needed Fb=gvsds2(DT/4Ts)    (7) where DT = Ts - Ta, Ts is stack gas temperature (K), and Ta is ambient air temperature (K). For determining plume rise, the momentum flux parameter, Fm (m4/s2), is calculated based on the following formula: Fm=gvs2ds2(Ta/4Ts)    (8)         Air pollution map (XY-Plane) produced by continuous discharge in time (two stacks). The red colour represents high pollutant concentrations. Wind: S (180 degrees).   Air pollution map (XY-Plane) produced by continuous discharge in time. The red colour represents high pollutant concentrations. Winds: NE (45 dregrees).   Canarina Algoritmos Numéricos, S.L. Environmental software solutions Canary Islands, Spain e-mail: contact us   CANARINA: Home - Air pollution · DISPER - Noise pollution · CUSTIC - Water pollution · DESCAR - Contact us DISPER: Air pollution dispersion · DISPER - Solutions - Data - Algorithms - Emissions - Graphs - ISC3 (VOL. 2) EMISSIONS: Emissions I - Emissions II - Emissions III - Pollutants I - Pollutants II GRAPHS: Graphs I - Graphs II - Graphs III - Graphs IV