Encyclopaedia Index

Var

---------------------------------------- Photon Help ----

This is the name of the variable to be chosen for the current surface plotting. Pressing <Return> will bring a list of variables saved in PHI(DA) file.


Variable

----------------------------------- Photon Help ----

This is the name of the variable to be chosen for the current contour. Pressing <Return> will bring up a list of variables saved in PHI(DA) file.


VARiables

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PHOENICS Input Language variables are organized in the following categories: CHARACters, INTegers, FLAGS, REALS, LOGICALs.

For a list of variables in a category, type the category name.


Variables in PINTO, increasing maximum number of

(see TR218)


Variables of the PHOENICS Input Language

(PIL) (see VARiables; also see entry)

(1) The following PIL variables were introduced or modified for PHOENICS version 1.5. For information on each, see .

    Variable                        New/modifed
    ----------------------------------------------------------
    ISOLX, ISOLY, ISOLZ             New
    ISOLBK                          New
    IVARBK                          New
    TRACE                           New
    NODEF                           New
    NOCOMM                          New
    NOCOPY                          New
    Q1QUIT                          New
    DMPSTK                          New
    DARCON                          Mew
    FIXFLU                          Value changed
    FIXVAL                          Value changed
    ITABL                           Default value changed
    ORSIZ                           Default value changed
    NPLT                            Default value changed

Variables, declaring in PIL

(see CHAR, REAL, INTEGER, BOOLEAN)


Variables, maximum values of

(see VARMAX)


Variables, minimum values of

(see VARMIN)


Variables, solving of

(see SOLVE)


Variables, specification of

(see RESTRT)


Variables, storing and solving of

(see SOLUTN)


Variables, storing of

(see STORE)


VARMAX

---- PIL real array; group 18 ----------- default=1.E10

If VARMIN(phi) is greater than or equal to its default value, namely -1.E10, VARMAX(phi) sets the maximum value which the variable phi may have anywhere in the domain.

If however VARMIN(phi) is less than its default value, VARMAX(phi) is the maximum absolute value of the increment of phi at any updating stage.

The second mode is not recommended, as it removes the ability to set upper and lower limits on the value of a variable. To set a maximum sweep-to-sweep increment for any SOLVEd variable, use the command:

SPEDAT(SET,MAXINC,phi,R,maximum increment)

Where 'maximum increment' is a REAL value (or any PIL expression that gives a REAL result).


VARMIN

---- PIL real array; group 18 ----------- default=-1.E10

If VARMIN(phi) is greater than or equal to its default value, namely -1.E10, it is the minimum value allowed to variable phi anywhere in the domain. If however VARMIN(phi) is less than its default value, it signals that VARMAX(phi) limits the increment of phi , not phi itself. The actual magnitude then has has no significance.

In the first mode ( i.e. VARMIN greater than -1.E10 ), if at any stage in the solution the value of phi in any cell is calculated to be less than VARMIN, it is set equal to VARMIN. Values closer to zero than the default can often be useful in preventing temporary, severe excursions of the field variables during iteration. Of course, any final solution in which the limits are active is unsatisfactory, and would generally indicate that the prescribed value of VARMIN was too large.

The second mode ( i.e. VARMIN less than -1.E10 ), is useful for controlling potentially divergent flow simulations; for it sets limits on the adjustments made.

The second mode is not recommended, as it removes the ability to set upper and lower limits on the value of a variable. To set a maximum sweep-to-sweep increment for any SOLVEd variable, use the command:

SPEDAT(SET,MAXINC,phi,R,maximum increment)

Where 'maximum increment' is a REAL value (or any PIL expression that gives a REAL result).