pycontrails.models.ps_model.ps_nominal_optimize_mach¶

pycontrails.models.ps_model.ps_nominal_optimize_mach[A: (ndarray, float)](aircraft_type, aircraft_mass, cost_index, level, *, air_temperature=None, northward_wind=None, eastward_wind=None, sin_a=None, cos_a=None, q_fuel=43130000.0, engine_deterioration_factor=0.025)¶

Calculate the nominal optimal mach number for a given aircraft type.

This function is similar to the ps_nominal_grid method, but rather than maximizing engine efficiency by adjusting aircraft, we are minimizing cost by adjusting mach number.

Parameters:

aircraft_type (str) – The aircraft type.
aircraft_mass (A) – The aircraft mass, [\(kg\)].
cost_index (A) – The cost index, [\(kg/min\)], or non-fuel cost of one minute of flight time
level (A) – The pressure level, [\(hPa\)]. If a numpy.ndarray is passed, it is assumed to be one dimensional and the same length as the``aircraft_mass`` argument.
air_temperature (A | None, optional) – The ambient air temperature, [\(K\)]. If None (default), the ISA temperature is computed from the level argument. If a numpy.ndarray is passed, it is assumed to be one dimensional and the same length as the aircraft_mass argument.
air_temperature (A | None, optional)
northward_wind (A | None = None, optional) – The northward component of winds, [\(m/s\)]. If None (default) assumed to be zero.
eastward_wind (A | None = None, optional) – The eastward component of winds, [\(m/s\)]. If None (default) assumed to be zero.
sin_a (A | None = None, optional) – The sine between the true bearing of flight and the longitudinal axis. Must be specified if wind data is provided. Will be ignored if wind data is not provided.
cos_a (A | None = None, optional) – The cosine between the true bearing of flight and the longitudinal axis. Must be specified if wind data is provided. Will be ignored if wind data is not provided.
q_fuel (float, optional) – The fuel heating value, by default q_fuel.
engine_deterioration_factor (float, optional) – The engine deterioration factor, by default PSGridParams.engine_deterioration_factor.

Returns:

xarray.Dataset – The nominal performance grid. The grid is indexed by altitude. Contains the following variables:

"mach_number": The mach number that minimizes segment cost
"fuel_flow" : Fuel flow rate, [\(kg/s\)]
"engine_efficiency" : Engine efficiency
"aircraft_mass" : Aircraft mass, [\(kg\)]

Raises:

KeyError – If “aircraft_type” is not supported by the PS model.
ValueError – If wind data is provided without segment angles.