eSTOMP

Grid Card Options (e-W)

Cartesian

For the Cartesian coordinate system, the terms west, south, and bottom refer to the negative x-, y-, and z-directions, respectively, and the terms east, north, and top refer to the positive x-, y-, and z-directions, respectively.  Negative dimensional values are not recognized, and axes are defined positive toward increasing node numbers.

Uniform Cartesian

A “right-handed” system with the longitudinal axis (z-direction) aligned with the negative gravitational vector and uniform grid spacing. In this case, the grid cell dimension in each direction is specified.
(Non-uniform) Cartesian
A “right-handed” system with the longitudinal axis (z-direction) aligned with the negative gravitational vector and non-uniform grid spacing. Either the locations of the cell edges are specified, or the number of cells of each cell size are specified. In each case, there must be one more value than the number of grid cells specified in each corresponding direction.  

Grid spacing specification options 

Cell Surface Location
In this case, the absolute locations of the cell edges are specified and there is one more value than the number of grid cells in the corresponding direction.  Cell edge locations can be specified using either a local or global coordinate system. Therefore, the origin of the grid need not be 0,0,0.
Count and cell size
In this case, the first value must be the cell surface location at the origin, but after that, the number of cells and the cell size can be specified using the count@cell size syntax. The grid can be specified using either a local or global coordinate system. Therefore, the origin of the grid need not be 0,0,0.

Cartesian w/proc

Same as the Cartesian options defined above, but this option allows the user to specify the processor distribution in the x-, y- and z-coordinate directions.

Uniform Cartesian w/proc

A “right-handed” system with the longitudinal axis (z-direction) aligned with the negative gravitational vector and uniform grid spacing. In this case, the grid cell dimension in each direction is specified.

(Non-uniform) Cartesian w/proc

A “right-handed” system with the longitudinal axis (z-direction) aligned with the negative gravitational vector and non-uniform grid spacing. Either the locations of the cell edges are specified, or the number of cells of each cell size are specified. In each case, there must be one more value than the number of grid cells specified in each corresponding direction.  

Grid spacing specification options 

Cell Surface Location
In this case, the absolute locations of the cell edges are specified and there is one more value than the number of grid cells in the corresponding direction.  Cell edge locations can be specified using either a local or global coordinate system. Therefore, the origin of the grid need not be 0,0,0.
Count and cell size
In this case, the first value must be the cell surface location at the origin, but after that, the number of cells and the cell size can be specified using the count@cell size syntax. The grid can be specified using either a local or global coordinate system. Therefore, the origin of the grid need not be 0,0,0.

Cylindrical

For the cylindrical coordinate system, the terms west, south, and bottom refer to the negative r-, θ-, and z-directions, respectively, and the terms east, north, and top refer to the positive r-, θ-, and z-directions, respectively. Negative dimensional values are not recognized, and axes are defined positive toward increasing node numbers.

Uniform Cylindrical

The longitudinal axis (z-direction) is aligned with the negative gravitational vector and the radial (r–direction) and azimuthal (θ-direction) axes are constrained to a horizontal plane.  In this case, the grid cell dimension in each direction is specified.

(Non-uniform) Cylindrical

The longitudinal axis (z-direction) is aligned with the negative gravitational vector and the radial (r–direction) and azimuthal (θ-direction) axes are constrained to a horizontal plane. Either the locations of the cell edges are specified, or the number of cells of each cell size are specified. In each case, there must be one more value than the number of grid cells specified in each corresponding direction.  

 

Boundary fitted grids

The key words “boundary fitted grids” in the grid card are used to specify that a boundary fitted grid will be used. The code will then read an external file containing the coordinates for all the cell corner points. The number of cells in each principal coordinate direction also need to be specified. The format for the external file is described in the following and an example is given in the attached file “bfg_grids.txt”.

1st line

Number of X-Direction cell corner points (nxc)*, number of Y-Direction cell corner points (nyc), number of Z-Direction cell corner points (nzc),
2nd line

X coordinates for all the corner points with sequence as { k = 1 : nzc; { j =1 : nyc; { i = 1 : nxc}}}

3rd line

Y coordinates for all the corner points with same sequence as X;
4th line

Z coordinates for all the corner points with same sequence as X;

*nxc = “Number of X-Direction Grid Cells”+1, likewise for the other two directions.

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