windpowerlib.density.ideal_gas¶
-
windpowerlib.density.
ideal_gas
(pressure, pressure_height, hub_height, temperature_hub_height)[source]¶ Calculates the density of air at hub height using the ideal gas equation.
This function is carried out when the parameter density_model of an instance of the
ModelChain
class is ‘ideal_gas’.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 equations are used [1] [2] [3]:
and [4]:
- with:
- T: temperature [K], : density [kg/m³], p: pressure [Pa]
is the height of the measurement or model data for pressure, is the specific gas constant of dry air (287.058 J/(kg*K)) and is the pressure at hub height .
References
[1] Ahrendts J., Kabelac S.: “Das Ingenieurwissen - Technische Thermodynamik”. 34. Auflage, Springer-Verlag, 2014, p. 23 [2] Biank, M.: “Methodology, Implementation and Validation of a Variable Scale Simulation Model for Windpower based on the Georeferenced Installation Register of Germany”. Master’s Thesis at RLI, 2014, p. 57 [3] Knorr, K.: “Modellierung von raum-zeitlichen Eigenschaften der Windenergieeinspeisung für wetterdatenbasierte Windleistungssimulationen”. Universität Kassel, Diss., 2016, p. 97 [4] Deutscher Wetterdienst: http://www.dwd.de/DE/service/lexikon/begriffe/D/Druckgradient_pdf.pdf?__blob=publicationFile&v=4