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convert units using Froude and Reynolds similitude

Project description


Convert quantities between model and prototype scale using Froude and Reynolds similitude.


pip install scaling


>>> from scaling import FroudeConverter
>>> froude = FroudeConverter()

>>> # Convert model value of 200 mm to prototype value (m) with scale of 10
>>> froude.model_to_proto(200, length_scale=10, input_unit='mm', target_unit='m')

>>> # Get Froude scaling exponent for quantities of time
>>> froude.scaling_exponent('s')

>>> # Get length, mass and time dimensions for quantities of energy
>>> froude.dimensions('kJ')
'L^2 M^1 T^-2'

Dataframes are also accepted, and specific units can be specified for the values in the index.

>>> T = 2
>>> H = 100

>>> # Generate regular waves with height=100mm, and period=2s
>>> t = np.arange(0, 10.1, 0.1)
>>> eta = 0.5 * H * np.sin(t * 2 * np.pi / T)

>>> df_model = pd.DataFrame(index=t, data=eta)
>>> df_model.columns = ['$\eta$ (mm)']
>>> = 'Time (s)'

>>> df_model.plot()


>>> # Convert to prototype dimensions, with length scale=25
>>> df_proto = froude.model_to_proto(

>>> df_proto.columns = ['$\eta$ (m)']
>>> df_proto.plot()


scaling uses pint for unit and dimension conversions. pint is able to interpret a wide range of different input units.

>>> # Convert water head model value (mm) to prototype pressure value (kPa)
>>> froude.model_to_proto(10, length_scale=100, 'mm.H20', 'kPa')

>>> # Demonstrate different ways of specifying units of newtons
>>> froude.dimensions('N')
'L^1 M^1 T^-2'
>>> froude.dimensions('newton')
'L^1 M^1 T^-2'
>>> froude.dimensions('kg.m/s/s')
'L^1 M^1 T^-2'
>>> froude.dimensions('kilogram.metre/second^2')
'L^1 M^1 T^-2'

Froude scaling reference

Quantity Dimensions Scaling exponent
Length L^1 λ^1
Mass M^1 λ^3
Time T^1 λ^0.5
Velocity L^1 T^-1 λ^0.5
Acceleration L^1 T^-2 λ^0
Force L^1 M^1 T^-2 λ^3
Pressure L^-1 M^1 T^-2 λ^1
Overtopping L^2 T^-1 λ^1.5

Reynolds scaling reference

Quantity Dimensions Scaling exponent
Length L^1 λ^1
Mass M^1 λ^3
Time T^1 λ^2
Velocity L^1 T^-1 λ^-1
Acceleration L^1 T^-2 λ^-3
Force L^1 M^1 T^-2 λ^0
Pressure L^-1 M^1 T^-2 λ^-2
Overtopping L^2 T^-1 λ^0

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