CFD Utilities Files

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   program usflowinterp

!  Purpose:
!
!     Interpolate flow field data from a US3D flow solution on to target points
!     defined in the specified form such as a Plot3D multiblock grid.  This was
!     prompted by the need to set up line-of-sight data for radiation calcula-
!     tions, analogous to flow_interp which is restricted to structured multi-
!     block flow solutions.
!
!  Method:
!
!     The flow grid may contain mixed cell types defined in the Fluent format.
!     An ADT (alternating digital tree) search tree is built from all of the
!     flow field cells.  The search for each target point always returns the
!     cell closest to the target, and the point not outside that cell that is
!     closest, along with corresponding interpolation coefficients for the cell
!     which can be used to interpolate the flow variables from the cell vertex
!     values.  This implies use of vertex-centered flow data.  If the input data
!     are cell-centered, they will be converted to the vertices internally here.
!
!     Potential Issue:  Indications elsewhere are that all zones of an un-
!                       structured dataset contain the same kind of cells.
!                       Cross that bridge if we come to it.
!
!  Control File (Standard Input):
!
!     Usflowinterp control file
!     cylinder.dat             ! Input grid + flow field data file
!     1                        ! 1|2|? = Tecplot|x|? input volume data format
!     T                        ! T|F = formatted | unformatted input volume
!     T                        ! T|F = cell-centered | vertex-centered
!     los.g                    ! Target point file name
!     1                        ! 1|2 = Plot3D/structured | Tecplot/unstructured
!     los.f                    ! Interpolated flow file name (same format)
!
!  History:
!
!     03/08/2022     D.A.Saunders  Initial design.
!     03/28-31/2022    "     "     Initial testing; seems to be working.
!     04/04/2022       "     "     Combining of zones and moving centroid data
!                                  to the vertices are now done in the
!                                  triangulation_io package.
!     04/20/2022       "     "     So is determining %nvertices (via new public
!                                  subroutine get_element_type).
!
!  Author:  David Saunders, AMA, Inc. at NASA Ames Research Center, CA.
!     
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