Code Manual for CONTAIN 2.0 - Federation of American Scientists

to the cell height if one is given in the GEOMETRY block. The average velocity of debris for this
case, V3,a,g,will be V@t if VNOST = GFT is specified and v~,Ou, otherwise. The average velocity of ~
debris for this case beginning with its entry into the cell is given by
v
d3,avg
= ~$lG
[
+ ts72G + ts>3&i 2 (6-118)
t,, +t,2+t,3
,,!
If the slips in Equation (6-2) is greater than one for any field in any cell, then the relative velocity
is given by
v= = ‘m ( ‘@’ ‘d%% - ‘ww 1)
As for the other cases, when slip is ignored, v~,,v~is dropped from the above equation.
6.3.7 Trapping Model Sensitivity Coefficients
1
(6-1 19)
In addition to the four trapping models and their various options and inputs, three sensitivity
coefilcients are provided to facilitate performing trapping sensitivity calculations. These coefficients
are:
a~,~ = slowest allowable trapping rate (default= O)
A max = fastest allowable trapping rate (default= ~)
J. mu] = trapping rate multiplier (default= 1)
These three coefficients can be specified by the user in the input file using the TRAPMIN,
TRAPMAX, and TRAPMUL keywords (see Section 6.4). Regardless of the trapping model
selected, the trapping rate k‘ actually used is obtained as follows:
where ~ is the trapping rate defined by the above trapping rate models.
(6-120)
The k~d coefficient is useful for exploring the sensitivity of a simulation to trapping rate in a relative
manner. The other two are useful for limiting the calculated trapping rate to fall within known
reasonable bounds.
6.4 Chemical Reactions
Chemical reactions are modeled to occur during a DCH event if reactive metals are present in the
dispersed debris fields
reactions are treated in
and if the atmosphere contains oxygen or steam. The following chemical
the model