# Geometrical properties of thermodynamic averages¶

## Description¶

This treatment computes 0D and 2D geometrical properties of a 2D section resulting from a cut with a revolution surface around the x-axis of an axisymmetric configuration. The following picture illustrates the computed 0D properties:

The following picture illustrates the computed 2D properties:

## Construction¶

```
import antares
myt = antares.Treatment('thermogeom')
```

## Parameters¶

**base**:`Base`

The input

**base**on which geometrical properties will be computed. Read section*Preconditions*to know the assumptions on this**base**. This input**base**is modified in-place. Read section*Postconditions*for more details.

**cartesian_coordinates**:`list(str)`

, default=*[‘x’, ‘y’, ‘z’]*Ordened names of the cartesian coordinates.

**cylindrical_coordinates**:`list(str)`

, default=*[‘x’, ‘r’, ‘theta’]*Names of the cylindrical coordinates: the axis of rotation (axial coordinate), the distance to this axis (radius), and the azimuth.

**def_points**:`list(tuple(float))`

, default=*None*List of coordinates of 2 points in the cylindrical coordinates system (only axis and radius). The first point gives the location of the hub. The second point gives the location of the shroud. These points do not necessarily belong to the hub nor to the shroud.

## Preconditions¶

The treatment must be applied on a mono-zone **base** containing a 2D section
resulting from a cut with a revolution surface around the ‘x’-axis of an
axisymmetric configuration.
This Zone must contain only one Instant (steady-state).

The specified coordinates must be available at nodes.
The rotation axis is the Cartesian first component of **cartesian_coordinates**.

The pitch of the row(s) is necessary : it can be available as an attribute called ‘pitch’ in the zone in mono-row case, but must be available at cells in multi-row case.

## Postconditions¶

The input **base** is modified in-place.

The **base** contains cartesian coordinates of normals, surfaces (see
‘base.compute_cell_normal’ for naming conventions) and cylindrical coordinates
at cells (same name than **cylindrical_coordinates**) and h/H local to the
surface (called ‘h_H’) at nodes.
The **base** is extended with one attribute named ‘0D/Geometry’, which is a
dictionary with variables:

**Xmin, Rmin**Coordinates (in the unit of the input data) of the hub point in the (x, r) plane.

**Xmax, Rmax**Coordinates (in the unit of the input data) of the shroud point in the (x, r) plane.

**Veine**Length (in the unit of the input data) between the hub and the shroud in the surface.

**Angle**Angle (in degrees) between the x-axis and the projection of the surface in the (x, r) plane.

**Area**The area (in the unit of the input data) of the surface on 360 degrees.

**Blade_ratio**Ratio of (in %) of the blade area on the surface with blades.

**Normal_x, Normal_r**Coordinates of a unit normal of the surface in cylindrical coordinates.