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DESCAR:

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Data I

Data II Advantages Average

Import Commands Graphs I

Graphs II Algorithms I Algorithms II Algorithms III Algorithms IV Algorithms V Algorithms VI Algorithms VII Pollutants I Pollutants II

The sea I

The sea II

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DESCAR software: algorithms VI

                               

2.3 Near mixing zone and distant mixing zone

 

We need to know the place where the plume centerline crosses the water surface or picnocline layer. To calculate this point we will use Ua and the vertical velocity 

Multiport diffuser.- W=1,66(g’q)1/3 being W the vertical velocity of the effluent (m/s).

 

Separated ports.- W=6,3(g’Qb/H)1/3 .

 

Single port.- W=6,3(g’Q/H)1/3.

 

In the last two cases, H will be replaced by ymax when the water is stratified. The point localization with regard to the place where the plume centerline crosses the surface, gives us the near and distant mixing zone definitions.

 

2.4 Concentration calculation

 

The concentration value in a plume point is determined by the X,Y,Z coordinates and is given by the equation:

 

C(X,Y,Z)=(C0/S) F0(t)F1(t)F2(Y,t)F3(Z,t)

C0=pollutant concentration in the effluent

S=initial dilution

 

being t=X/Ua. F0(t) takes into account non-conservative pollutants and is equal to:

 

F0(t)=10-t/T90

    

The F0, F1, F2 and F3 functions depend on being in near or distant mixing zone.

 

(a) Near mixing zone:

In such a case, the equations are

 

F1(t)=1

F2(Y,t)=(1/2)[erf[(B/2+Y)/(σy21/2)]+ erf[(B/2-Y)/(σy21/2)]]

F3(Z,t)=(1/2)[erf[(e+Z)/(σz21/2)]+ erf[(e-Z)/(σz21/2)]]

 

being σy=(2Kyt)1/2 and σz=(2Kzt)1/2. The program calculats erf function by numerical integration. The the precision of integration method depends on the parameter N_int. Increasing N_int value, we increase the numeric convergence but we will need more time of calculation. We should look for an optimized value of N_int.

 

 

 

Algorithms I -  Algorithms II - Algorithms III - Algorithms IV - Algorithms V - Algorithms VI - Algorithms VII

 

                                                                               

Canarina Algoritmos Numéricos, S.L.

Environmental software · environmental software solutions

Canary Islands, Spain

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European Union · network on Pollution

Member of MAPO: European network on Marine Pollution.

Project funded by the European Commission

through the 6th Framework Programme for Research and Development

 

 

                               

 

DESCAR: water pollution - Solutions - Advantages - Price - Data I - Data II - Advantages - Temporal average - Import - Commands - Graphs I - Graphs II - Algorithms I -  Algorithms II - Algorithms III - Algorithms IV - Algorithms V - Algorithms VI - Algorithms VII - Pollutants I - Pollutants II - The sea I - The sea II - Google maps - GIS

 

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