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README 2023-09-30 3.2 kB
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
   program scale_flow
!
!  Description:
!
!     SCALE_FLOW is a companion in a limited sense to SCALE_GRID, which can
!     apply numerous standard transformations to a multiblock structured grid's
!     coordinates.  This companion is limited to scaling or shifting one or more
!     of the (flowfield?) functions in the input PLOT3D-type function file, in
!     all blocks or in a subset (or subsets) of the blocks.  [An additional
!     option is described below.]
!
!     Belated realization:  Actually, ADJUST_GRID and ADJUST_FLOW are now the
!     recommended pair for applying standard transformations.
!
!     There is no need to read the accompanying grid file.  The entire function
!     file is read before a loop over scaling/shifting options is entered.
!     The block dimensions and number of functions are not changed.
!
!     Extending SCALE_GRID was considered but rejected because it uses the
!     deprecated cfd_io_package.  Handling of 2D grids is eschewed initially.
!
!  Belated realization:
!
!     Actually, ADJUST_GRID and ADJUST_FLOW are now the recommended pair for
!     applying standard transformations.  SCALE_GRID is deprecated.  But
!     SCALE_FLOW is retained as the name for this more specialized utility.
!
!  Motivation:
!
!     Difficulties with calculating an initial solution on an unaligned 3D whole
!     body grid prompted SCALE_FLOW: conventional wisdom avoids revolving and
!     reflecting an aligned 2D solution for fear of locking in some symmetric
!     wake feature such as a disk shock that is a 2D artifact.   Starting the 3D
!     whole body solution from scratch can prove difficult or even impossible.
!     This utility will allow revolving and reflecting the 2D state variables
!     then artificially introducing some asymmetry in one or more of those state
!     variables, probably in just the aft blocks, in the hope of providing a
!     decent starting guess with a fully developed wake that will not preserve
!     any of the initial 2D artifacts.
!
!     Another option is included in the hope of assisting calculations from
!     scratch (essentially from free-stream conditions everywhere): these
!     solutions can stall out (NaN) with the wake only partially developed.
!     Copying k planes from the partially-developed wake into the remaining
!     downstream k planes may be beneficial (for DPLR-type grids with a single
!     layer of blocks).
!
!  Control:
!
!     A few prompts serve to control this utility.
!
!  History:
!
!    09/19/2023  D.A.Saunders  Initial design.
!    09/20/2023    "      "    Implementation and testing.
!    09/23/2023    "      "    Reading of large function files can be very slow
!                              because of %q(m,i,j,k) indexing of xyzq_io.  We
!                              really need a %q(i,j,k,m) option.  A bit more
!                              run-time dialogue was desirable.
!    09/25/2023    "      "    A %q(i,j,k,m) option is now available and used.
!
!  Author:  David Saunders, AMA, Inc. at NASA Ames Research Center, CA.
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Source: README, updated 2023-09-30