F-array locations,reserving the

(see NFUSER)

F-array size,increasing the size of

(see DIMENSIONING)

F-array access

(see F-array access)

FALSDT

---- PIL integer flag; value=1; group 17 -

FALSDT.... should be entered as the second argument of RELAX when the false-time-step mode of under-relaxation is to be used. The third argument is then the value of this time step.

False-time-step relaxation

See RELAX)

FAN, a PHOENICS-VR object type

A FAN object is used to declare an area of fixed velocity. An optional swirling component can be specified for round fans. See the description in the PHOENICS_VR Reference Guide, TR326

FDFSOL

-------------------------------------

FDFSOL=T activates fully-developed channel flow features. See PHENC entry: FULLY-DEVELOPED FLOW.

FEMGEN/FEMVIEW

FEMGEN/FEMVIEW is a finite-element modelling and result-presentation system.

FEMGEN/FEMVIEW combines, in a single application, powerful, menu-driven pre and post-processing, incorporating interactive geometry-based grid-generation and versatile results display, including a facility animate result presentations.

Two interface programs have been created by FEMVIEW Limited for the transfer of data between FEMGEN/FEMVIEW and PHOENICS.

The FEMGEN-to-PHOENICS program allows a PHOENICS BFC-grid to be created using FEMGEN. Boundary conditions (inlets, outlets, walls, PATCHES a blockages) can be specified with FEMGEN, which then creates a skeleton Q1 file with PHOENICS settings for the boundary conditions.

The PHOENICS-to-FEMVIEW interface can be used for the analysis of problems in all grid geometries handled by PHOENICS (Cartesian, cylindrical-polar and BFC).

The interface programs work with PHOENICS direct-access and XYZ file

FII1

FII1 is an integer index, usable in subroutines called from GROUND, for accessing the 2D array of values, pertaining to the current IZ-slab, of: values for the current phase-1 variable at the phase interface.

FII2

FII2 is an integer index, usable in subroutines called from GROUND, for accessing the 2D array of values, pertaining to the current IZ-slab, of:
values for the current phase-2 variable at the phase interface.

FIINIT

---- PIL real array; default=1.E-10 (for newly-declared variables);

FIINIT(phi)....initial value of the variable to be taken over the whole field, unless further modified by PATCH and INIT.

FIINIT values are set, in GROUP 11, as follows:-

FIINIT(C1)=0.00139 , or equivalently FIINIT(16)=1.39E-3

If it is desired to use, as the initial field of a given variable, the field obtained (and SAVEd ) on a previous run, then set,

FIINIT(variable name)= READFI.

See INIT for information regarding PATCH-wise initializations.

FINE_GRID_VOL, a PHOENICS-VR object type

A FINE_GRID_VOL object is used to declare a rectangular volume within which the grid is refined. See the description in the PHOENICS_VR Reference Guide, TR326

Fill/Isolines

(Contour Menu)--------------------------- Photon Help ----

[Fill/Isolines] switches between filled contour and contour lines.

FINE-GRID EMBEDDING

(See also entry: PARSOL)

Accuracy of simulation often requires that the computational grid should be very fine around regions of the domain exhibiting steep gradients of temperature, concentration, density or other significant fluid property.

In earlier versions of PHOENICS, this entailed also extending the fineness into regions where it was not required.

Fine-grid embedding, now available, renders this unnecessary; for it is possible to refine the grid ONLY where necessary.

Click here to see an application to a "three-part" airfoil,

See the PHENC entry: multi-block grids and fine-grid

FIRE objects

1. the heat of combustion per unit mass of burning material;
2. the mass of air containing the oxygen consumed by unit mass of burning material;
3. the rate of entry into the gas phase of combustible material or information from which that rate can be deduced.

Sometimes, as when a gas-supply pipe ruptures, the rate can be estimated from known conditions in the pipe. More often however the only reasonable presumption is the 'worst-case' scenario, namely that the combustion rate is that which corresonds to the highest rate at which the necessary oxygen can be transported to the fire.

This rate can be estimated by representing the fire as a linearised (negative) source of oxygen within the volume believed to be occupied by the fire.

That volume is itself of course a guess. If the object were a sofa on to which gasoline had been copiously spilled, the volume of the flames would exceed that of the sofa; but, if the only combustible were the pyrolised fabric, the volume would be less.

The fire-object representations which are provided by the FLAIR menu of the PHOENICS Satellite do not, at the present time, include the oxygen-transport option. All that is needed however is to insert in the Q1:

• SOLVE(MO2)
• PATCH{FIRE,VOLUME,appropriate indices)
• COVAL(FIRE,MO2,large number,0.0)

First sweep

(index number of (see FSWEEP)

First-phase cartesian velocity resolute

(see UCRT , VCRT, WCRT character)

First-phase fluid,mixing length scale of

(see EL1)

First-phase temperature

(integer index for) (see TEM1)

FIXCOR

---- PIL real; default=1.E10; group 6 --- -

FIXCOR....parameter used to anchor coordinate points in sub-domains specified by FIXDOM, when the MAGIC(L) option is used.

When FIXCOR is set to a value less than 1.E10, the effect is to introduce a resistance to movement of the coordinates within the sub-domain specified by FIXDOM. The smaller the value of FIXCOR, the less the resistance is. This device can be used to reduce the movements of the coordinates which the Laplace solver brings about.
See FIXDOM, MAGIC for related information.

FIXDOM

---- Command; group 6 ---------------

FIXDOM....command used to specify (up to 10) sub-domains in which it is desired to keep the coordinate points fixed when the Laplace corner-coordinate solver, MAGIC(L), is invoked. It has seven arguments: the first specifies the sub-domain number (from 1 to 10); the remaining six arguments locate, by their index numbers, the sub-domain boundaries of the corner coordinates that are to be kept fixed, ie.

FIXDOM(sub-domain no.,first I,last I,first J,last J,first K,last K).

When the DOMAIN over which MAGIC(L) operates includes a solid, the FIXDOM command may be used to prevent the Laplace solver from moving the corner coordinates that correspond to the locations of the solid.

It is also useful where one wishes to retain a fine-grid zone, which otherwise MAGIC(L) might coarsen.

See MAGIC, FIXCOR for related information.

Fixed-pressure boundary

(see OUTLET)

Fixed-flux boundary condition

(seeFIXFLU)

Fixed-value boundary condition

(see FIXVAL, and FIXP)

FIXFLU

---- PIL real flag; value=2.0E-10; group -

FIXFLU....is a coefficient name recognized in the third argument of COVAL, to be used to indicate a fixed-flux condition.

See COVAL for further information.

FIXP

------ PIL real flag; value=1.0; group 13 - -

FIXP....is a coefficient name recognized in the third argument of COVAL, to be used when the external pressures are fixed. FIXP corresponds to coefficient for pressure of numerical value 1.0 . This means that the mass flow is taken as the geometrical area, given by the PATCH type, times the difference between the external pressure and in-cell pressure. The 4th argument of COVAL specifies the external pressure.

FIXP does not necessarily fix the internal pressures: see COVAL.

FIXVAL

---- PIL real flag; value=2.0E10; group 1 -

FIXVAL....is a coefficient name recognized in the third argument of COVAL, to be used to indicate a fixed-value condition. See COVAL for further information.

FLAG

FLAGS are those variables which have been assigned values of particular significance to PHOENICS. The word is used in responses, for example that for FIXVAL (above).

Their assignments must not be altered.

The following FLAG variables are recognised in PIL:

FLAG

------ PIL logical; default=F; group 25 --- -

FLAG....flags the entry and exit to all major subroutines in EARTH, within the iteration, slab, sweep and time ranges specified by ITHDB1, ITHDB2, IZDB1, IZDB2, ISWDB1, ISWDB2, ISTDB1 and ISTDB2. It is useful in determining the location of at which failures occur, and may be used in conjunction with SEARCH.

FLAGS

--------------------------------------

>>> See the Encyclopaedia entry 'FLAG'.

FOLIAGE, a PHOENICS-VR object type

A FOLIAGE object is used to model the interaction between the wind and forested areas, as well with other types of tree or plant canopy, such as for example urban plantings of avenues or clumps of trees. See the description in the PHOENICS_VR Reference Guide, TR326

Formula 1 in Schools

This is a Special-Purpose Product geared to calculating lift and drag on CO2-powered model racing cars designed by schools.

For more information see the CHAM brochure or visit the F1 in schools website.

Four-fluid model

See PHENC entry 4-fluid model

FRAC-array method

(see TR218)

FRAME

---- Autoplot Help ----

FR[AME]

Axes will form complete frame around plot. Axis markings will appear on the inside of all four sides. Return to normal axes by repeating FRAME. (Defaulted ON).

See also HELP on : AXES, BOX, TICK

Frame

FRAME, a concept used in grid generation Also see the Encyclopaedia entry 'GSET'.

Frame, setting of

(see GSET(F,...))

From

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

The first GEOMETRY element to be [DELETE]ed or turned ON/OFF.

FSWEEP

---- PIL integer; default=1; group 11 --- -

FSWEEP....index number of first sweep. On RESTRT runs, set FSWEEP to the last sweep of the previous plus one, as a bookkeeping aid.

FUEL

FULL

---- Autoplot Help ----

FU[LL]

Produces a plot which fills the screen. Default text size is size 2.

See also HELP on : BIG, LITTLE, PAGE

FULL

(View Menu)--------------------------------------- Photon Help ----

[Full] redraws the current screen contents in the full size window without menu. Any key stroke or mouse click will bring the system back to menu mode. All plots saved as either in graphic file or as hard copy will be in this full screen mode.