Code Manual for CONTAIN 2.0 - Federation of American Scientists

crossover parameter y always selects the averaged expression ~~jj (i.e., y = 1) over the range of 6‘s
(i.e., e z 6 z sly) corresponding to the possible types of metastable stratifications.
The definition of the asymptotically correct head AP~,jj is
AP’ gr,ij=+V -H;)% (4-9)
where H ‘i= Hi - ~,i,l is tie gfi center-of-volume ‘levation ‘n i>adjusted ‘or submergence? if ~YJ
and H; = Hj - A~,j,z. This asymptotically correct head cannot be modified through user input.
The definition of the VDI head AP~r,ijused away from the well-mixed asymptotic limit is
AP ‘&,ij=gpi Hi -H’ + F..p. + 1-F.. p. H’ -H’ +gp. I-I’-H!
(4-lo)
(’ bid Ml J L J
The definitions of the elevations H:, H;, H;, and H; and the VDI parameter Fij depend on two user
options, controlled by the MSTABLE and RESOLVHD keywords discussed below. The Fij
parameter gives the location of the VDI in the flow path in terms of a fraction of the effective length
of the path in the direction from i to j. The default treatment is a dynamically calculated Fij, as
discussed below, in which the interface is assumed to span the entire elevation difference between
the gas centers of volume, with adjustments for any submergence of the flow path ends. If
MSTABLE is specified, then Fij is simply set to %, a value which corresponds to using the averaged
density over the elevation span normally spanned by the VDI model. Specification of the
RESOLVHD keyword invokes a treatment whereby the elevation difference normally spanned by
the VDI is restricted to the elevation difference between the flow path ends, and the appropriate cell
density is used within a cell to span the elevation change between the gas center of volume and the
flow path end. In other words,
H; = H: if the RESOLVHD keyword has not been specified for the path
= HI if the RESOLVHD keyword has been specified for the path, and
H;= H; if the RESOLVHD keyword has not been specified for the path
= H2 if the RESOLVHD keyword has been specified for the path,
where HI and Hz are the attachment elevations of the flow path ends to the cells i and j, respectively,
as shown in Figure 4-4. Note that RESOLVHD will have no effect if the flow paths are
(coincidentally) attached at the cell center at each end.
The MSTABLE and RESOLVHD options have been made available to recover the old gravitational
head modeling used in code versions prior to CONTAIN 1.2, and also to add flexibility to the present
modeling. (Use of MSTABLE, and explicit specification of RESOLVHD and the appropriate
elevations for all flow paths will allow the user to recover the “old,” averaged-density gravitational
head formulation recommended in prior versions, at least in cases in which the pool does not cover
gas path inlets and significant displacement of gas centers of elevation by the pool does not occur.)
Rev. O 4-23 6/30/97