fastoad.models.performances.mission.polar module

Aerodynamic polar data.

class fastoad.models.performances.mission.polar.Polar(cl: numpy.ndarray, cd: numpy.ndarray, alpha: Optional[numpy.ndarray] = None)[source]

Bases: object

Class for managing aerodynamic polar data.

Links drag coefficient (CD) to lift coefficient (CL). It is defined by two vectors with CL and CD values. If a vector of angle of attack (alpha) is given, it links alpha and CL

Once defined, for any CL value, CD can be obtained using cd(). For any alpha given, CL is obtained using :meth:’cl’.

Parameters

cl – a N-elements array with CL values
cd – a N-elements array with CD values that match CL
alpha – a N-elements array with angle of attack corresponding to CL values

property definition_cl: The vector that has been used for defining lift coefficient.

property definition_cd: The vector that has been used for defining drag coefficient.

property definition_alpha: The vector that has been used for defining AoA.

property optimal_cl: The CL value that provides larger lift/drag ratio.

cd(cl=None)[source]

Computes drag coefficient (CD) by interpolation in definition data.

Parameters: cl – lift coefficient (CL) values. If not provided, the CL definition vector will be used (i.e. CD definition vector will be returned)
Returns: CD values for each provide CL values

cl(alpha)[source]

The lift coefficient corresponding to alpha (rad)

Parameters: alpha – the angle of attack at which CL is evaluated
Returns: CL value for each alpha.