## Definition

A 2D grid is a face support, on which the user can evaluate a spatial quantity.

## Use

A 2D grid is used for:

• plotting of scalar spatial quantities as color-shading isovalues
• plotting of scalar spatial quantities as arrows
• exportation of values

## Shapes of 2D grids

2D grids can be of rectangular, annular, cylindrical or spherical shape.

## 2D grid and infinite box

The spatial support of the 2D grid type can be extended beyond the bounded study domain.

## Mesh

The mesh of a 2D grid is based on a user-defined discretization: computation points are regularly spaced on the surface of the support.

## Rectangular 2D grid

A 2D grid of rectangular type is built in one of the planes XY, YZ or XZ and characterized by a position, dimensions and discretizations.

An example of the definition of a rectangular 2D grid is presented below.

Definition of the "Rectangular" 2D grid

The position is defined by:

• a coordinate system
• an origin (in the coordinate system) The dimensions are defined by:

• characteristics along the two main axes of the plane:
• a value in a positive direction of the axis
• a value in a negative direction of the axis

The discretization are defined by a number of elements along the two main axes of the plane ## Annular 2D grid

A 2D grid of annular type is built in the XY plane of the coordinate system for definition and is characterized by a position, dimensions and discretizations.

An example of the definition of an annular 2D grid is presented below.

Definition of the "Annular" 2D grid

The position is defined by:

• a coordinate system
• an origin (in the coordinate system) The dimensions are defined by:

• an opening angle θ about the Z-axis with θ = θmin - θmax:

• a minimal value of θ

• a maximal value of θ

The discretization are defined by:

• a number of elements along the radius • a number of elements along the angle θ Angle unit of coordinate system Angle θ
degree 0<| θ | ≤ 360
radian 0<| θ | ≤ 2 π

## Cylindrical 2D grid

A 2D grid of cylindrical type is characterized by a position, dimensions and discretizations.

An example of the definition of a cylindrical 2D grid (a part of a hollow cylinder) is presented below.

Definition of the "Cylindrical" 2D grid

The position is defined by:

• a coordinate system
• an origin (in the coordinate system) The dimensions are defined by:

• a height:
• a value in a positive direction of the Z-axis
• a value in a negative direction of the Z-axis
• an opening angle θ about the Z-axis with θ = θmin - θmax:

• a minimal value of θ

• a maximal value of θ

The discretization are defined by:

• a number of elements along the angle θ (angle about the Z-axis) • a number of elements along the Z-axis Angle unit of coordinate system Angle θ
degree 0<| θ | ≤ 360
radian 0<| θ | ≤ 2 π

## Spherical 2D grid

A 2D grid of spherical type is characterized by a position, dimensions and discretizations.

An example of the definition of a spherical 2D grid (a part of a hollow sphere) is presented below.

Definition of the "Cylindrical" 2D grid

The position is defined by:

• a coordinate system
• an origin (in the coordinate system) The dimensions are defined by:

• an opening angle θ about the Z-axis with θ = θmin - θmax:
• a minimal value of θ
• a maximal value of θ
• an angle φ about the origin in the plane passing through the Z-axis with φ = φmin - φmax :
• a minimal value of φ
• a maximal value of φ  The discretizations are defined by:

• a number of elements along the angle θ (angle about the Z-axis) • a number of elements along the angle φ (angle about the origin in the plane passing through the Z-axis) Angle unit of coordinate system Angle θ Angle φ
degree 0<| θ | ≤ 360 0<| φ | ≤ 180
radian 0<| θ | ≤ 2 π 0<| φ | ≤π