Encyclopaedia Index


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The Y component.


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Once activated, GRID, VECTOR, CONTOURS and SURFACE will be plotted on each Y plane in the current plotting region. In the case of STREAMLINES this option together with the [IniPln] option can be used to specify the initial particle seeding plane.

See also: [PlanNo], [Outline]


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[Y] the surface contours will be generated on Y plane. Usually two out of three directions (e.g. X, Y or Z) will need to be specified, to generate a cross-hatched surface.

Y-direction coordinates, setting of

(see YFRAC real array, Group 4)

Y-wise variables

See PHENC: X-wise variables

Y-Z print-out of fields

(see YZPR logical, Group 23)


---- PIL real Array; Group 6 ----------------

YC....is the Satellite array used for body-fitted coordinate grids to represent the Cartesian coordinate y of the corners of the continuity cells. See also XC, ZC and BODY-F.

YC is also a GROUND-accessible real function returning the corner-coordinate value. See also SUBROU.


When the Q1 file contains BFC=T and STORE(YCEN), the values of the cell-centre y-coordinates are printed in the result file. They may also be accessed and used by In-Form statements.


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[YF] specifies the starting J index of the current plotting region. The default value is 1.


----- PIL real array; default=100*1.0; gro -

YFRAC....Array for use in setting the y-direction coordinates of the "north" faces of the computational cells used for the balances of all variables except (for NY greater than 1) y-direction velocity components V1 and V2.

Distances are measured from the low-y (i.e. extreme south) boundary of the flow domain.

YFRAC values may be set indirectly by means of the commands GRDPWR,SUBGRD or by one of the two methods described for TFRAC.

In polar coordinates (CARTES=F and BFC=F), the YFRACs measure distance from the inner boundary of the domain, which is separated from the axis of symmetry by the radial distance RINNER.



Integer index; used in GROUND.

YG2D....EARTH index used to access the 2D array of values, pertaining to the current slab, of the distances of the centres of the continuity cells from the y=0.0 plane (for CARTES=T or BFC=T) or cylinder (for CARTES=F and BFC=F).See RINNER.

Note that this index is present only if CALL MAKE(YG2D) is present in Group 1, Section 1 of GROUND.


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[YL] specifies the last J index of the current plotting region. The default value is NY+1 for GRID and NY for other plotting elements.


----------- PIL logical; group 25 ---------

YPLS... is used to activate the calculation and print-out of the dimensionless wall distance y+ for all wall PATCHes. See the help and encyclopaedia entries on TURBUL, and WALPRN for further information.


YRAT is a Fortran real variable used in GROUND. It represents the multiplier of the previous YVLAST which gives the current YVLAST.



Integer index.

YV2D....EARTH index, as for YG2D, except that the north faces of cells are involved, not cell centres. Unlike YG2D, YV2D has no significance when BFC=T.

Note that this index is present only if CALL MAKE(YV2D) is present in Group 1, Section 1 of GROUND.


---- PIL real; default=1.0; group 4 -----

YVLAST....is the extent of the grid in the y-direction; and the V is a reminder that its extremity is occupied by a v-velocity location.

In parabolic calculations, YVLAST can be changed as a function of downstream location by means of the parameter AZYV.


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YZPR....may be set T to print fields in y-z ( ie. constant-x ) planes. See also XZPR.