Encyclopaedia Index

### 1. PIL variables and commands

1. Control variables
• CARTES
• RINNER
2. Direct setting
• NX XULAST XFRAC
• NY YVLAST YFRAC
• NZ ZWLAST ZFRAC
• LSTEP TFIRST TLAST TFRAC
3. Regions
• NREGX IREGX GRDPWR(X
• NREGY IREGY GRDPWR(Y
• NREGZ IREGZ GRDPWR(Z
• TFIRST NREGT IREGT GRDPWR(T
4. Objects

### 2. Set grid and time steps by regions

See examples: cartesian and polar.

NREGX, IREGX, GRDPWR(X (Same for Y, Z, T)

• NREGX....is the number of regions in the X direction. By default, every region contains 1 cell and has an extent of 1 metre (or 1 radian if CARTES=F). Default NREGX=1.

• IREGX....is the current region number in the X direction. Note that the GRDPWR command will only apply to the current region. See GRDPWR for further details. Default IREGX=1.

• GRDPWR....command to set intervals for the current region in X, Y or Z, and time dimensions, thus:

• Format: GRDPWR(X,num,ext,pwr)
• num -- Number of cells in the current region
Negative num will set symmetric power law
• ext -- Extent of the current region in meter
• pwr -- Distribution power in the region
Negative pwr will set the power law from the high end.

• Example using NREGX, IREGX, GRDPWR(X :

### 3. Set grid and time steps by objects

See examples: cartesian and polar.

##### Warning: When hand-editing a Q1 file, it is unwise to use both region and object commands; for the latter imply some of the former, but not vice versa.

• RSET(D,...) Set the Solution Domain
• Format: RSET(D,name,dx,dy,dz,icol,idash)
• name -- String of up to 8 alpha-numerical characters, name of the solution domain
• dx -- X size of the solution domain
• dy -- Y size of the solution domain
• dz -- Z size of the solution domain
• icol -- Colour index for displaying the solution domain
• idash -- Line type index for displaying the solution domain

The Solution Domain is the space in which the Cartesian or polar grid is generated, ie the grid must be contained within the Solution Domain.

The default Solution Domain is a 1 metre cube; the default name of the Solution Domain is "NOTSET". dx, dy and dz must be greater than zero (even for 1- or 2-D grids).

In a polar domain, dx represents the total angle in radians.

The colour index varies from 1 to 15 on a colour screen, the colour range is: 1 for white, 2 for dark blue, ... , 15 for red. On a monocrome screen, the colour index must be 1. Line styles vary from 0 to 4, with 0 for a solid line.

• RSET(B,...) Set an Object
• Format: RSET(B,name,x0,y0,z0,dx,dy,dz,icol,idash)
• name -- String of up to 8 alpha-numeric characters, the name of the object
• x0 -- X position of the low-south-west corner of the object
• y0 -- Y position of the low-south-west corner of the object
• z0 -- Z position of the low-south-west corner of the object
• dx -- X size of the object
• dy -- Y size of the object
• dz -- Z size of the object
• icol -- Colour index for displaying the object
• idash -- Line type index for displaying the object

This command is used to define or modify objects. An object can be either a three-dimensional block, or a two-dimensional panel.

Any object must be defined within or on the boundary of the solution domain. Dx, dy and dz must be greater than (or equal to) zero. Region boundaries are automatically created on the boundaries of an object (see GRDPWR, NREGX etc.). Up to 50 objects can be defined.

• RSET(M,...) Match Grid
• Format: RSET(M,ni,nj,nk)
• ni -- Number of cells in X direction
• nj -- Number of cells in Y direction
• nk -- Number of cells in Z direction

This command matches a grid with dimension (ni,nj,nk) to the solution domain, taking all objects into account.

Region boundaries in all three directions are automatically defined around objects so that all faces of an object lie on region boundaries.

This command distributes the total number of cells in each direction across regions in the most uniform way. ni must not be less than number of regions in the x-direction, likewise for nj and nk.

• RSET(X [RSET(Y, RSET(Z, RSET(T are similar]

RSET(X,...) Cut regions and modify grid in X direction

• Format: RSET(X,L,0,pos) -- cut region at X = pos
• RSET(X,ireg,ncell,power) -- set X grid in region ireg
• pos -- real value or expression, the position where a region boundary is set
• ireg -- the current region number
• ncell -- number of cells to be set in the region
• power -- the grid distribution power

This command has two functions. The first splits one region into two at a specified position; the second sets the grid distribution inside the specified region.

To split a region, the position must be inside the solution domain, and measured along the x-axis from x=0.

If the position coincides with an existing region boundary, this command has no effect.

• RSET(V,...) Set Graphic View Control
• Format: RSET(V,iopt)
• iopt -- integer to control the display of objects
• iopt = 0 switch off the display
• iopt = 1 switch on geometry
• iopt = 2 switch on geometry and name

This command controls whether or not the Solution Domain and Objects are shown when a GDRAW or VIEW command is issued. When they are shown on the screen, their names also appears. The display colour and line styles are set by RSET(D,... and RSET(B,...

• RSET(U,...) Set uniform time step
• Format: RSET(U,t0,dt,nt)
• t0 -- The starting time
• dt -- The total time duration
• nt -- Number of time steps

This command sets a uniform time-step distribution over the defined time duration starting at t0.

See example.