CFD Utilities Files

TRI_TO_QUAD Description:

   Interpolate an unstructured surface flow solution to a structured mesh.
   Initially, the input is a single-zone Tecplot surface triangulation with
   a variable number of quantities defined at each vertex, and the target
   mesh is a multiblock PLOT3D-type grid.  Output is in either Tecplot or
   PLOT3D form.

Input Tecplot data format (original, vertex-centered):

   VARIABLES = "X", "Y", "Z", "TEMP", "PRESS", "CP", "MACHE", "ASOUNDE", ..
   ZONE N=96000, E=32000, F=FEPOINT, ET=TRIANGLE
   0.000000  0.000000 0.000000 2838.386719 51330.925781 1.552663 0.609412 .
   0.000883 -0.007150 0.113643 2838.386719 51330.925781 1.552663 0.609412 .
   0.000883  0.000000 0.113868 2838.386719 51330.925781 1.552663 0.609412 .
   ::::::::::::::::
   ::::::::::::::::
   4.882953  0.000000 0.011285 950.867676 16.506409 -0.001166 5.062649 ...
   1 2 3
   4 5 6
   7 8 9
   10 11 12
   ::::::::
   ::::::::
   95992 95993 95994
   95995 95996 95997
   95998 95999 96000

Alternative cell-centered Tecplot input format (DPLR overset grid tools):

   TITLE     = ""
   VARIABLES = "x"
   "y"
   "z"
   "p"
   "Chm"
   "h"
   "qw"
   "Re_c"
   ZONE T="ZONE 001"
    STRANDID=0, SOLUTIONTIME=0
    Nodes=9367, Elements=18438, ZONETYPE=FETriangle
    DATAPACKING=BLOCK
    VARLOCATION=([4-8]=CELLCENTERED)
    FACENEIGHBORCONNECTIONS=55014
    FACENEIGHBORMODE=LOCALONETOONE
    FEFACENEIGHBORSCOMPLETE=YES
    DT=(SINGLE SINGLE SINGLE SINGLE SINGLE SINGLE SINGLE SINGLE )
    3.756540120E-01 3.601163924E-01 3.451932967E-01 3.309260905E-01  ...
   ::::::::::::::::

Control file format (standard input):

   TRI_TO_QUAD control file
   xxxx.xxx      ! Surface triangulation and flow solution (Tecplot format)
   1             ! 1 => vertex-centered/Tecplot; 2 => cell-centered/Tecplot
   xxxx.xxx      ! Target grid (PLOT3D multiblock)
   T             ! T|F = formatted|unformatted
   xxxx.xxx      ! Output file 1 (grid file if PLOT3D format)
   xxxx.xxx      ! Output file 2 (function file if PLOT3D, else 'none')
   T             ! T|F = formatted|unformatted
   0.0001        ! Distance tolerance for target pt. inside solution grid
  [7.890     0.  ! Optional X & F; if x > X, set finterp(:) = F]

Method:

   >  The surface triangulation is read as one zone and converted to an
      ADT (Alternating Digital Tree) for search purposes.  If the function
      values are cell-centered, they are interpolated to the cell vertices
      first.  No unique best interpolation method exists. The area-weighted
      averaging used here suffices for typical triangulations.
   >  Target blocks are processed in order (read and written as needed).
   >  For each target point, the ADT search locates the nearest pt. on the
      surface triangulation (never outside it).  The function values can
      then be interpolated with the indicated trilinear coefficients.
   >  Optionally, target points beyond the indicated X will be set to the
      indicated F (probably zero, as for radiation on an aft body).

Note:

   This program still uses the original Tecplot I/O package.  It has not
   been updated to use the I/O package version prompted by Tecplot 360.

History:

   03/04/05  DAS  Initial implementation for vertex-centered function data.
   03/07/05   "   Changed name from SURFACE_FLOW_INTERP to TRI_TO_QUAD in
                  anticipation of a QUAD_TO_TRI analog.
   08/29/08   "   Added optional X and F to deal with radiative heating
                  that goes to zero beyond some X for CEV.
   03/15/10   "   Provided for DPLR/Overset-related triangulated input data
                  (type 2, cell-centered Tecplot format).
   08/08/13   "   All ADT variants are in one module now with generic
                  build_adt and search_adt interfaces.
   07/02/14   "   The tri_* modules come from triangulation_io.f90, not
                  tecplot_io_module (comments were wrong).
   07/23/18   "   Updated to use the Tecplot 360 version of tecplot_io, and
                  also the extended triangulation_io, which now handles
                  multi-zone triangulations and cell-centered functions.
   05/03/22   "   One glitch following triangulation_io extensions.

Author:  David Saunders, ELORET Corporation/NASA Ames Research Center, CA
                         Later with ERC, Inc. and AMA, Inc. at NASA ARC.