Raise ValueError for unphysical WindTrubine

Author: vezeli

windpowerlib/wind_turbine.py

@@ -163,6 +163,11 @@ def __init__(self, hub_height, nominal_power=None, path='oedb',
                 if self.rotor_diameter is None and turbine_data is not None:
                     self.rotor_diameter = float(turbine_data['rotor_diameter'])
 
+        if self.rotor_diameter:
+            if self.hub_height <= 0.5*self.rotor_diameter:
+                msg = "1/2*rotor_diameter cannot be higher than hub_height"
+                raise ValueError(msg)
+
         if self.power_curve is None and self.power_coefficient_curve is None:
             msg = ("The WindTurbine has been initialised without a power curve"
                    " and without a power coefficient curve.\nYou will not be"