windpowerlib.density.barometric¶
- windpowerlib.density.barometric(pressure, pressure_height, hub_height, temperature_hub_height)[source]¶
Calculates the density of air at hub height using the barometric height equation.
This function is carried out when the parameter density_model of an instance of the
ModelChain
class is ‘barometric’.- Parameters:
pressure (pandas.Series or numpy.array) – Air pressure in Pa.
pressure_height (float) – Height in m for which the parameter pressure applies.
hub_height (float) – Hub height of wind turbine in m.
temperature_hub_height (pandas.Series or numpy.array) – Air temperature at hub height in K.
- Returns:
Density of air at hub height in kg/m³. Returns a pandas.Series if one of the input parameters is a pandas.Series.
- Return type:
pandas.Series or numpy.array
Notes
The following equation is used [1] [2] :
- with:
T: temperature [K], h: height [m], : density [kg/m³], p: pressure [Pa]
is the height of the measurement or model data for pressure, the ambient air pressure, the ambient density of air, the ambient temperature and the temperature at hub height .
Assumptions:
Pressure gradient of -1/8 hPa/m
References