Add to docstrings

Author: SabineHaas

windpowerlib/density.py

@@ -42,7 +42,9 @@ def temperature_gradient(temp_air, temp_height, hub_height):
     with:
         T: temperature [K], h: height [m]
 
-    :math:`h_{T,data}` is the height in which the temperature is measured.
+    :math:`h_{T,data}` is the height in which the temperature :math:`T_{air}`
+    is measured and :math:`T_{hub}` is the temperature at hub height
+    :math:`h_{hub}` of the wind turbine.
 
     Assumptions:
 
@@ -143,7 +145,7 @@ def rho_barometric(pressure, pressure_height, hub_height, temp_hub):
     :math:`h_{p,data}` is the height of the measurement or model data for
     pressure, :math:`p_0` the ambient air pressure, :math:`\rho_0` the ambient
     density of air, :math:`T_0` the ambient temperature and :math:`T_{hub}` the
-    temperature at hub height.
+    temperature at hub height :math:`h_{hub}`.
 
     Assumptions:
 
@@ -198,8 +200,10 @@ def rho_ideal_gas(pressure, pressure_height, hub_height, temp_hub):
     with:
         T: temperature [K], :math:`\rho`: density [kg/m³], p: pressure [Pa]
 
-    :math:`R_s` is the specific gas constant of dry air (287.058 J/(kg*K)) and
-    :math:`p_{hub}` is the pressure at hub height.
+    :math:`h_{p,data}` is the height of the measurement or model data for
+    pressure, :math:`R_s` is the specific gas constant of dry air
+    (287.058 J/(kg*K)) and :math:`p_{hub}` is the pressure at hub height
+    :math:`h_{hub}`.
 
     References
     ----------

windpowerlib/power_output.py

@@ -204,9 +204,11 @@ def p_curve_density_corr(v_wind, rho_hub, p_values):
         v: wind speed [m/s], :math:`\rho`: density [kg/m³]
 
     :math:`v_{std}` is the standard wind speed in the power curve
-    (:math:`v_{std}`, :math:`P_{std}`).
+    (:math:`v_{std}`, :math:`P_{std}`),
     :math:`v_{site}` is the density corrected wind speed for the power curve
-    (:math:`v_{site}`, :math:`P_{std}`).
+    (:math:`v_{site}`, :math:`P_{std}`),
+    :math:`\rho_0` is the ambient density (1.225 kg/m³)
+    and :math:`\rho_{site}` the density at site conditions (and hub height).
 
     It is assumed that the power output for wind speeds above the maximum
     wind speed given in the power curve is zero.

windpowerlib/wind_speed.py

@@ -57,8 +57,9 @@ def logarithmic_wind_profile(v_wind, v_wind_height, hub_height, z_0,
     .. math:: v_{wind,hub}=v_{wind,data}\cdot\frac{\ln\left(\frac{h_{hub}}
         {z_{0}}\right)}{\ln\left(\frac{h_{data}}{z_{0}}\right)}
 
-    :math:`h_{data}` is the height at which the wind speed
-    :math:`v_{wind,data}` is measured.
+    :math:`h_{data}` is the height in which the wind speed
+    :math:`v_{wind,data}` is measured and :math:`v_{wind,data}` is the wind
+    speed at hub height :math:`h_{hub}` of the wind turbine.
 
     Parameters `v_wind_height`, `z_0`, `hub_height` and `obstacle_height` have
     to be of the same unit.
@@ -123,8 +124,8 @@ def v_wind_hellman(v_wind, v_wind_height, hub_height, hellman_exp=None,
         v: wind speed, h: height, :math:`\alpha`: Hellman exponent
 
     :math:`h_{data}` is the height in which the wind speed
-    :math:`v_{wind,data}` is measured and :math:`h_{hub}` is the hub height of
-    the wind turbine.
+    :math:`v_{wind,data}` is measured and :math:`v_{wind,data}` is the wind
+    speed at hub height :math:`h_{hub}` of the wind turbine.
 
     For the Hellman exponent :math:`\alpha` many studies use a value of 1/7 for
     onshore and a value of 1/9 for offshore. The Hellman exponent can also