What are you looking for?
Canarina Environmental Software

Canarina DISPER software · air · environment health and safety management · algorithms 13

Courtesy of Canarina Environmental Software

Canarina DISPER software · air · environment health and safety management

All Conditions - Distance Less Than Distance to Final Rise.

Where gradual rise is to be estimated for unstable, neutral, or stable conditions, if the distance downwind from source to receptor, x, is less than the distance to final rise:

he=hs+1.60 [(Fb x2)1/3/us]      (21)

This height will be used only for buoyancy dominated conditions; should it exceed the final rise for the appropriate condition. For momentum dominated conditions, the following equations are used to calculate a distance dependent momentum plume rise:

a)     unstable conditions:

he=hs+[3Fmx/(betj2us2)]1/3      (22)

where x is the downwind distance, with a maximum value xmax:

xmax=4ds(vs+3us)/(vsus)   for Fb=0                 (23)

xmax=49 Fb5/8             for 0 < Fb < 55 m2s3      (24)

xmax=119 Fb2/5            for Fb > 55 m2s3         (25)

b) stable conditions:

he=hs+(3Fm)1/3{sin[x s1/2/us]}1/3[betj2uss1/2]-1/3   (26)

where x is the downwind distance, with a maximum value xmax:

xmax=0.5 pi us/s1/2            (27)

The jet entrainment coefficient, betj, is given by,

betj=(1/3)+(us/vs)       (28)

If the distance-dependent momentum rise exceeds the final rise for the appropriate condition, then the final rise is substituted instead.

················································································································

Canarina DISPER software · air · environment health and safety management

It is interesting for health and safety, safety cans, safety management, environment health and safety management, health and safety management, health safety and environment, health management