Code Manual for CONTAIN 2.0 - Federation of American Scientists

keyword will result in the oversized aerosols being transfemed to the lower
cell pool, if defined, in the cell specified by the cell OVERFLOW keyword, ~
as discussed in Section 7.1. If a pool is not defined in that cell, the aerosols
will be placed in the waste location in that cell. In contrast to previous
practice, the transferred aerosols will be assumed to have an enthalpy
corresponding to the conditions of the originating cell, not the destination
cell. CAUTION: This keyword represents a non-upward compatible change
in the code. If the TRAPO~ keyword is not specified, aerosols previously
transferred to floors and pools will go to the waste location instead. Since
these aerosols have become too large to be described in the aerosol mesh,
such transfers are nonmechanistic and should be reassessed by the user.
TRAPUNFL the keyword to trap aerosol particles that have become too small for the
aerosol size mesh and keep them from being transferred to the waste location
of the cell in which the condition originated. Specification of this keyword
will result in the undersized aerosols being retained in the smallest size class.
CAUTION: 7’kiskeyword represents a non-upward compatible change in the
code. If the TRAPUNFL keyword is not specified, aerosols previously
transferred to floors and pools or retained in the aerosol mesh will go to the
waste location instead. Since these aerosols have become too small to be
described in the aerosol mesh, such transfers are nonmechanistic and should
be reassessed by the user.
More complete definitions of the physical parameters introduced above are given in Chapter 7.
The global aerosol input allows the user control over the disposition of the aerosol mass in particles
that become either too large or too small for the aerosol mesh. This mass is reported in the aerosol
waste location output and reported by default in the waste repository of the mass and energy
accounting scheme for the cell in which the oversized or undersized condition arose. This is
consistent with the use of the waste repository to keep track of mass and energy transfers without
mechanistic basis or with an ambiguous transfer path. The TRAPOVFL and TRAPUNFL keywords
alter the disposition of the oversized or undersized aerosols and enable behavior similar to that
previously available. It should be noted that the enthalpy associated with the transfer of oversized
aerosols corresponds to donor cell conditions, as opposed to downstream cell conditions, consistent
with energy conservation. This feature may make a significant dl~erence in pool temperature if
TMPOVFL is specified and the cell OVERFLOW option is used to direct oversized aerosols to a
diflerent cell from that in which the condition arose.
Through the AERTIM global table option, the user may specify the aerosol size distribution
parameters “amean” and “avar” (discussed more fully along with the “mapaer” variable below) as
a fimction of time. The AERTIM option uses a number of global tables to specify this time dependence,
with one table speci~ing “amean” or “avar” for one aerosol component. The FLAG, X, and
Y keywords are standard table keywords defined in Section 14.4.2. Other keywords and values
associated with the AERTIM option are discussed below. The user should consider the AERTIM
Rev O 14-36 6/30/97