Encyclopaedia Index
EARCON EARDAT EARTH EASP1 EAST EBO ECHO Eddy-break-up model EDITOR EF EF0 EGWF EL1 EL2
Electric Potential; EPOT ELEMENT
ELLIPTIC_FLOW
ELSE ELSOA END ENDIT ENLARGING_SPACE_IN_PINTO ENTHALPY_SOURCE

ENUFIT ENUFSW ENUL ENULA ENUT ENUTA ENUTB ENVIRONMENT EPOR EQDVDP EQUAL EQUATIONS_SOLVED_BY_PHOENCS EQUVEL

ERRORS ESCAPE ESTER_ELECTROLYTIC_SMELTER EWAL EWALL EWP EX
EXEC EXECUTABLE EXIT EXPERT EXPLICIT FORMULATION EXPLOITS, the SPP for explosions, etc EXTENDED_SIMPLE_CHEMICALLY-REACTING_SYSTEM EXTERNAL_HEAT-TRANSFER_LAWS EXTERNAL_PRESSURES EXTRAPOLATE


EARCON

(see CONFIG)


EASP1

EASP1 is an integer index, usable in subroutines called from GROUND, for accessing the 2D array of values, pertaining to the current IZ-slab, of any variable which the user cares to insert.

In order to provide storage for the array indexed by EASP1, subroutine MAKE must be called from GROUND. Similar indices are EASP2, EASP3, ... , EASP20. Some of these are used in GREX and the GX suite, so users should check the listings carefully to avoid conflicting usage. See PHENC entry: F-array.


EAST

------ PIL real flag; value= 2.0; group 13 -

EAST....is a PATCH type used for setting sources per unit east ( ie. larger-x ) area by way of COVAL in group 13. See also integer function EAST in PHENC entries: F-array and Subroutines.


ECHO

------ PIL logical; default=T; group 20 --- -

ECHO = T in the Q1 causes the data settings to be "echoed" to the top of the RESULT file.

It should be noted that EARTH checks some data for consistency, and may make changes to enforce consistent data settings. The data printed by EARTH when ECHO is T will reflect any such changes.

This print-out is produced by a call to the subroutine DATPRN made in subroutine GREX3.


Eddy-break-up model

See PHENC entry Eddy-break-up model


EGWF

----- PIL logical; default=F; group 13 ----

EGWF..., when T, causes the EARTH-Generated-Wall-Function feature to be activated, so that for a variety of simple wall functions, WALL PATCHes are not required on solids specified by means of the PRPS variable. See the encyclopaedia entries for: WALL and EARTH-generated wall functions for further information.


EL2

------- PIL real; default= 0.0; group 9, se -

EL2....is the mixing-length scale of the second-phase fluid, used similarly to EL1EL1.


EL2A

------ PIL real; default= 0.0; group 9, se -

EL2A....GROUND parameter used in phase-2 length-scale formulae. Further parameters of the same kind are: EL2B,EL2C.


EL2D

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

EL2D... is used to specify the second-phase free-stream fluid velocity in certain turbulence model options. See the help and encyclopaedia entries on TURBUL, and GXLEN for further information.


EL2E

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

EL2E... is used to specify the second-phase nozzle-discharge velocity in certain turbulence model options. See the help and encyclopaedia entries on TURBUL, and GXLEN for further information.


ELLIPTIC flow problems

The term "elliptic" is used in PHOENICS as the opposite of "parabolic" (see relevant PHENC entry). It signifies that there is no predominant direction of flow which would allow PARAB to be set true, and the resultant savings of computer time and storage to be made.


ELSE

-------------- Advanced PIL command --- -

ELSE is an element of the PIL IF construct. See the HELP entry on IF for further information.


ELSOA

----------- PIL real; group 13 -----------

ELSOA... is a constant used by GXLESO in the calculation of a length-scale source for the two-fluid model of turbulence. See TURBUL for further information.


Enlarging the working space with PINTO

(see TR218)


Enthalpy source,multiplying factor for built-in

(see HUNIT, Group 8)


EPOR

------ PIL integer name; default=0; group 7 -

EPOR.... indicates which whole-field store will be used for the porosity of the east face in response to the command STORE(EPOR). Once stored, this field should be initialized in group 11. The field values are set to 1.0 by default.


EPOT

is the name reserved for electric potential, i.e. voltage.

Solution for this variable is initiated by inclusion of:
 SOLVE(EPOT)
in the Q1 file.

It is a variable for which the differential equation possesses only diffusion terms, so that the implied TERMS statement is:
 TERMS(EPOT,N,N,Y,N,N,N)
which statement the user does not need to supply.

Boundary conditions and sources may be supplied in the usual way.

The distribution of electrical conductivity, i.e. the 'exchange coefficient' of EPOT, is most conveniently specified by means of an In-Form statement of the kind:
 (property PRNDTL(EPOT) is FORMULA with QUALIFICATIONS)

whereby it should be noted that it is not necessary to supply a minus sign so as to indicate that the property is a conductance rather than a true Prandtl number.

Thus:  PRNDTL(EPOT) = - CONSTANT
and
 (property PRNDTL(EPOT) is CONSTANT)
have the same effect.

Values of the electrical conductivity, or rather its reciprocal, the resistivity, for common materials can be found by clicking here.


EQDVDP

---- PIL logical; default= F; group 8 --- -

EQDVDP....when T, sets the d(vel)/dp's of the first and second phases equal to the weighted average of the two, eg thus: d(U1)/dp = d(U2)/dp = r1* d(U1)/dp + r2* d(U2)/dp


EQUAL

---- Autoplot Help ----

EQ[UAL]

Enters "equal mode", in which plots are drawn so that both axes are scaled equally. This is the default for BFC grid file plots. See also HELP on : UNEQUAL


EQUAL command in AUTOPLOT

There may be occasions when it is desirable to have distances along the axes equal in the two coordinate directions. This is achieved by using the command EQUAL. When EQUAL is used, either the full x-width or the full y-height will be used, but (usually) not both. To revert to the ordinary mode of operation, you should use the inverse command UNEQUAL.

EQUAL is the default when plotting BFC grids.

Note that, when EQUAL is used, the SCALE X and SCALE Y commands require an additional piece of information, since rescaling in (for instance) the x-direction will affect the y-scaling also. After one of these commands, the following question will appear:

CONSTANT VALUE OF Y? (or X).

You should respond with the value of y (or x) which is to remain at the same position on the screen after rescaling. Use of the MAGNIFY command instead of SCALE X or Y avoids this problem.

When one of the axes is logarithmic, exact equality of axis-distances may not be achieved, since the scales will always be forced to lie within the nearest powers of ten.

If the plot size is changed while in equal mode (by typing BIG, FULL, LITTLE or PAGE), a further SCALE command will be necessary to re-enforce equality of the axis markings.


Equations solved by PHOENICS

See PHENC items: Differential equations; Auxiliary equations; Finite-volume equations.


EQUVEL

EQUVEL is PIL logical variable which it is useful to set = T, when:

It can be regarded as an economising device; for it allows one set of velocities to be computed, rather than two.

Input-file library cases employing this device include:

483 484 485 w100 w468 w574 w576

An IPSA-based two-phase-flow Q1 can be converted to one based on the equal-velocity assumption simply by adding to the bottom of the Q1 file the line:


LOAD($W100)

or, to make what is being done even plainer:
L(EQUALVEL .

Here EQUALVEL is a non-PIL character string, which is declared in the always-loaded-first macro 014, where it is given the value $w100, which of course has the desired effect.

Reminder: the $ prevents the loading of a new case from over-writing pre-existing settings.


ESCAPE

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

ESC[ape]....causes a temporary escape to the operating system. The result of this command is system-dependent, and it may not be available on all implementations.


ESTER Electrolytic Smelter

ESTER is a PHOENICS add-on which enables PHOENICS to simulate the phenomena occurring in the electrolytic smelters for the production of aluminium from its oxide.


EWALL

----- PIL real flag; value=17.0; group 13 -

EWALL....is a PATCH type used in group 13 in conjunction with COVAL for representing the sources resulting from a wall at the east faces of the cells identified by PATCH. See WALL and WALLS for further information


EX

-------- PIL real array; default=*0.0; group -

EX....is an array used in connection with the DISTILled output facility. It is used to set the mean value of each variable in the domain of integration.

See DISTIL for further information.


EXEC

-------- PIL COMMAND

This command can be used to run any other program or batch file at a particular moment during the processing of a Q1 file.

The Pil command

EXEC(T/F,arg1,[arg2,arg3,...,argn])

will attempt to execute whatever executable or batch file is supplied as arg1. If the first argument is T, the process will run in a window. If it is F, it will run in the background. The further optional arguments arg2 - argn are supplied to the arg1 program as arguments. Thus

EXEC(T,xcopy,file1,file2,/p)

will execute the DOS command

xcopy file1 file2 /p

which copies file 1 to file 2 and asks for confirmation.

Note that if the program or batch file being run requires text input from the user, the EXEC(T form must be used as otherwise there will be no command prompt to accept the input and Satellite will appear to stall.


Executable

A self-contained program which can be run by directly loading it into the computer memory.


EXPERT

A set of 'auto-pilot' devices have been introduced which make 'in- flight' adjustments to the numerical parameters (such as relaxation factors) in order to speed up the convergence of the solution procedure.

For more information,

  1. see entry below
  2. see POLIS lecture on PHOENICS/EXPERT under 'Special Topics'
  3. see core library case 568

EXPERT

------------ PIL logical Switch ---------

EXPERT... when set to true, activates the built-in automatic of some relaxation parameters. To be effective, further parameters must be set. This is best done by inserting:
NOWIPE=T
LOAD(30) in the Q1 file, whereupon a complete group of settings is made. These can later be edited. See the lecture notes on EXPERT for further information.


EXPLICIT FORMULATION

See PHENC entries: implicit formulation; schemes


EXPLOITS, the special-purpose program for explosions, etc.

This program is one of those which were developed as part of the MICA project.

It is provides for the simulation of the phenomena of combustible-gas leakage fires and explosions, in such circumstances as arise in chemical plant and in off-shore oil platforms.

Click here for an early lecture on its capabilities,


External heat-transfer laws

PATCH and COVAL commands exist which facilitate inclusion of external heat loss by way of radiation (= a*(Ts**4-Test**4)) and free convection (= a*(Ts-Test)**n).

For more information, see the entry for PATCH.


External pressures,fixing of

(see FIXP)


EXTRAPOLATE

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

EXT[rapolate]....is a command that enables PHOTON to plot to the boundaries of the grid.

EXTRAPOLATE is entered as an alternative to PHI for the processing of the "fields" file from EARTH. It generates an additional "layer" of cells at both ends of the computational domain in each direction, and assigns values to each new node by extrapolation of the values at the two adjacent, inner nodes.

The values assigned to the new nodes are truncated, if needed, so that they do not exceed the maximum and minimum values in the original domain. (Use the command EXTRAPOLATE NOLIM to extrapolate without these limits.)

EXTRAPOLATE can also be used to obtain contour plots of one-dimensional problems.

See also: PHI


EXTRAPOLATE NOLIM

-------------------------EXTRAPOLATE NOLIM

EXT[rapolate] NOL[im]....is similar in function and usage to the EXTRAPOLATE command, but will allow the extrapolated values of the variables to lie outside the original range of values for the domain.

See also: EXTRAPOLATE


EXTrapolate command in PHOTON

The command EXT provides a means of plotting contours to the boundaries of the computational domain. When used instead of the PHI command to load the data file, EXT will cause the "fields file" (PHI or PHIDA) to be read in, and will generate an extra "layer" of cells that surrounds the old grid. Values for all the variables at these extra cells are then assigned by extrapolation of the values at the existing nodes.

In addition to plotting to the boundaries, the EXT command will also allow the plotting of contours in one-dimensional problems.


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