PHOTON

PHOTON and WinPHOTON

PHOTON (PHOENICS OuTput optiON) is an interactive graphics program, written in FORTRAN, which can be used to display the results of fluid-flow simulations generated by PHOENICS, or indeed by any other code which produces files in the PHOENICS format, whether for cartesian, polar or body-fitted-coordinate (BFC) grids.

PHOTON reads the PHI (or PHIDA) file written by EARTH and then, in response to instructions from a "PHOTON USE" file, from the keyboard, or from mouse movements over the PHOTON menu, represents the computed grid and the flow pattern graphically and colourfully on the VDU screen. For body-fitted-coordinate calculations to be properly displayed, the XYZ (or XYZDA) file containing cell-corner coordinates must also be read.

PHOTON can draw:-

grids, or grid outlines, over the whole or parts of the domain;
vector fields for velocity, heat flux or any other quantity;
contour plots for scalar variables such as temperature, pressure, concentration or turbulent kinetic energy;
streamlines; and
particle tracks.

Additional features include:

text annotation in a variety of text sizes;
use of colour on devices possessing that facility;
the ability to save pictures to a disk file;
the ability to operate from a command file; and
the ability to replay pictures aved in an earlier session.

Users issue instructions to PHOTON by typing commands on the keyboard or by pressing menu buttons. They can build up and edit pictures interactively, adding or deleting picture elements as they proceed. These picture elements can be viewed from any desired direction, and with any magnification.

PHOTON commands

The PHOTON commands are listed and described under individual PHOTON Help entries in the Encyclopedia.

When running PHOTON, to get help on any item listed above, type the item name followed by a question mark, e.g. 'CONTOUR OFF ?' Items marked with an asterisk (*) give help on selected topics, and are not PHOTON commands, while items marked (R) refer to subcommands of the REPLAY command. Commands marked (U) may only be issued from a USE file.

In help entries, command names are shown thus :-
CON[tour] ON <element number> where the minimum abbreviation for the command is shown in capitals, with the rest of the command in square brackets. Any abbreviation of the full name down to the minimum will be accepted. Parameters are shown in angle brackets; the program will prompt for essential parameters if they are not given on the command line.

PHOTON, disk file requirements

The configuration of PHOTON, in relation to the files it uses, is illustrated below

PGI stands for the PHOENICS Graphics Interface; it is the FORTRAN 'junction-box' which connects PHOTON to graphics software packages such as GKS, PLOT-10/TCS, etc, or to terminals for which direct device drivers are supplied.


         Help file                    Geometry file
                   \               /
    PHI/PHIDA       \             /    / - -  scratch
                _ _  |-----------| ---
    XYZ/XYZDA        |  PHOTON   |      / -   scratch
               _ _   |-----------| --- /
    USE file         |   PGI     |      / -   scratch
                    /|-----------| --- /
                   /       |     /
        TERMINAL  /  LOG file   / _ _ _   SAVE file

The Files Used by PHOTON

When PHOTON is used as a post-processor for EARTH- produced results, it requires access to the 'fields' file PHI (or PHIDA), which provides field values of all variables which are stored or solved. If flows are simulated in BFC (ie body-fitted coordinate) grids, PHOTON additionally requires access to the grid file XYZ (or XYZDA) which contains the grid coordinates.

When PHOTON is used as a pre-processor, for examination of BFC grids, it requires access only to the grid file. When PHOTON is used to replay previously stored pictures, neither a 'fields' file nor a grid file is needed.

PHOTON HELP

Photon Help ----

Help is available under the following headings :-


    BLOCK                    CLEAR                    CLEAR (R)
    COLOUR                   CONTOUR CLEAR            CONTOUR DELETE
    CONTOUR OFF              CONTOUR ON               CONTOURS
    COORDINATES              DASH                     DOMAIN
    DRAW (R)                 DUMP                     DUMP (R)
    END                      ESCAPE                   EXTRAPOLATE
    FILE (R)                 GEOMETRY (*)             GEOMETRY CLEAR
    GEOMETRY DELETE          GEOMETRY OFF             GEOMETRY ON
    GEOMETRY READ            GEOMETRY SAVE            GEOMETRY_CMDS (*)
    GRID CENTRE              GRID CLEAR               GRID DELETE
    GRID HATCH             GRID OFF                 GRID ON
    GRID OUT               GRIDS                    HATCH
    LIST (R)               LOG                      MAGNIFY GRID
    MIRROR                 MONOCHROME (R)           NEWS (*)
    NOCLEAR (R)            PAUSE                    PHI
    PICS (*)               PREFIX_FILE (*)          REDRAW
    REDRAW (R)             REPLAY                   RESET (R)
    ROTATE                 SAVE                     SCALE (R)
    SCREEN                 SENDP                    SENDP (R)
    SET                    SET AXES                 SET BOX
    SET CONTOUR FILL       SET CONTOUR SCALE        SET CONTOUR UNITS
    SET GEOMETRY           SET HOLD                 SET LHAND
    SET ORDER              SET POROSITY             SET PROPERTY
    SET RHAND              SET VECTOR AVERAGE       SET VECTOR BOUNDARY
    SET VECTOR CENTRE      SET VECTOR COMPONENTS    SET VECTOR KEY
    SET VECTOR PHASE       SET VECTOR REFERENCE     SET VECTOR UNITS
    SHIFT (R)              SHOW                     STOP
    STREAM                 STREAM 2DIMENSTION       STREAM 3DIMENSTION
    STREAM CLEAR           STREAM DELETE            STREAM OFF
    STREAM ON              SURFACE CLEAR            SURFACE DELETE
    SURFACE OFF            SURFACE ON               TEXT
    TEXT CLEAR             TEXT COLOUR              TEXT DELETE
    TEXT LIST              TEXT MOVE                TEXT REPLACE
    TEXT SIZE              TEXT UNDERLINE           UMAGNIFY GRID (U)
    UP                     UPAUSE (U)               UREWIND (U)
    USE                    USHIFT (U)               UTEXT (U)
    VECTOR CLEAR           VECTOR DELETE            VECTOR OFF
    VECTOR ON              VECTORS                  VIEW
    WHERE (R)              XYZ                      4VIEW (R)

To get help on any item listed above, type the item name followed by a question mark, e.g. 'CONTOUR OFF ?'. Items marked with an asterisk (*) give help on selected topics, and are not PHOTON commands, while items marked (R) refer to subcommands of the REPLAY command. Commands marked (U) may only be issued from a USE file.

Note also that PHOTON contains a built-in set of tutorials, which are accessed by typing m on the command line.

This Encyclopaedia article describes the pre-Windows PHOTON. Those who prefer the Windows 'look-and-feel' can read about the more-modern WinPHOTON by clicking here.

PHOTON help; further information

The following PHOTON items are provided here because they cannot be conveviently placed elsewhere in an alpahabetically- ordered encyclopaedia.