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particula.gas.properties.kinematic_viscosity

kinematic_viscosity

Kinematic viscosity for fluids.

Long Description

The kinematic viscosity (ν) is the ratio of the dynamic viscosity (μ) to the density (ρ).

Equation
  • ν = μ / ρ
Where
  • ν : Kinematic viscosity [m²/s].
  • μ : Dynamic viscosity [Pa·s].
  • ρ : Fluid density [kg/m³].
References
  • "Viscosity Conversion Formula," Wolfram Formula Repository, https://resources.wolframcloud.com/FormulaRepository/resources/Viscosity-Conversion-Formula
  • Wikipedia contributors, "Viscosity," Wikipedia, https://en.wikipedia.org/wiki/Viscosity#Kinematic_viscosity

get_kinematic_viscosity 

get_kinematic_viscosity(dynamic_viscosity: float, fluid_density: float) -> float

Calculate the kinematic viscosity of a fluid.

The function calculates ν by dividing the dynamic viscosity (μ) by the fluid density (ρ).

  • ν = μ / ρ
    • ν is Kinematic viscosity [m²/s].
    • μ is Dynamic viscosity [Pa·s].
    • ρ is Fluid density [kg/m³].

Parameters:

  • - dynamic_viscosity –

    Dynamic viscosity of the fluid [Pa·s].

  • - fluid_density –

    Density of the fluid [kg/m³].

Returns:

  • float –
    • The kinematic viscosity [m²/s].

Examples:

Example usage
import particula as par
par.gas.get_kinematic_viscosity(1.8e-5, 1.2)
# Output: ~1.5e-5
References
  • "Viscosity Conversion Formula," Wolfram Formula Repository. https://resources.wolframcloud.com/FormulaRepository/resources/Viscosity-Conversion-Formula
Source code in particula/gas/properties/kinematic_viscosity.py 
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@validate_inputs({"dynamic_viscosity": "positive", "fluid_density": "positive"})
def get_kinematic_viscosity(
    dynamic_viscosity: float,
    fluid_density: float,
) -> float:
    """Calculate the kinematic viscosity of a fluid.

    The function calculates ν by dividing the dynamic viscosity (μ)
    by the fluid density (ρ).

    - ν = μ / ρ
        - ν is Kinematic viscosity [m²/s].
        - μ is Dynamic viscosity [Pa·s].
        - ρ is Fluid density [kg/m³].

    Arguments:
        - dynamic_viscosity : Dynamic viscosity of the fluid [Pa·s].
        - fluid_density : Density of the fluid [kg/m³].

    Returns:
        - The kinematic viscosity [m²/s].

    Examples:
        ```py title="Example usage"
        import particula as par
        par.gas.get_kinematic_viscosity(1.8e-5, 1.2)
        # Output: ~1.5e-5
        ```

    References:
        - "Viscosity Conversion Formula," Wolfram Formula Repository.
          https://resources.wolframcloud.com/FormulaRepository/resources/Viscosity-Conversion-Formula
    """
    return dynamic_viscosity / fluid_density

get_kinematic_viscosity_via_system_state 

get_kinematic_viscosity_via_system_state(temperature: float, fluid_density: float, reference_viscosity: float = REF_VISCOSITY_AIR_STP, reference_temperature: float = REF_TEMPERATURE_STP) -> float

Calculate the kinematic viscosity of air by first computing its dynamic viscosity.

This function uses get_dynamic_viscosity(...) and divides by the given fluid_density to get the kinematic viscosity.

  • ν = μ / ρ
    • ν is Kinematic viscosity [m²/s].
    • μ is Dynamic viscosity [Pa·s].
    • ρ is Fluid density [kg/m³].
Where
  • ν is Kinematic viscosity [m²/s].
  • μ is Dynamic viscosity [Pa·s].
  • ρ is Fluid density [kg/m³].

Parameters:

  • - temperature –

    Desired air temperature [K]. Must be > 0.

  • - fluid_density –

    Density of the fluid [kg/m³].

  • - reference_viscosity –

    Reference dynamic viscosity [Pa·s].

  • - reference_temperature –

    Reference temperature [K].

Returns:

  • float –
    • The kinematic viscosity of air [m²/s].

Examples:

Example usage
import particula as par
par.gas.get_kinematic_viscosity_via_system_state(300, 1.2)
# Output: ~1.5e-5
References
  • "Sutherland's Formula," Wolfram Formula Repository, https://resources.wolframcloud.com/FormulaRepository/resources/Sutherlands-Formula
Source code in particula/gas/properties/kinematic_viscosity.py 
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@validate_inputs({"temperature": "positive", "fluid_density": "positive"})
def get_kinematic_viscosity_via_system_state(
    temperature: float,
    fluid_density: float,
    reference_viscosity: float = REF_VISCOSITY_AIR_STP,
    reference_temperature: float = REF_TEMPERATURE_STP,
) -> float:
    """Calculate the kinematic viscosity of air by first computing its dynamic
    viscosity.

    This function uses get_dynamic_viscosity(...) and divides by the given
    fluid_density to get the kinematic viscosity.

    - ν = μ / ρ
        - ν is Kinematic viscosity [m²/s].
        - μ is Dynamic viscosity [Pa·s].
        - ρ is Fluid density [kg/m³].

    Where:
        - ν is Kinematic viscosity [m²/s].
        - μ is Dynamic viscosity [Pa·s].
        - ρ is Fluid density [kg/m³].

    Arguments:
        - temperature : Desired air temperature [K]. Must be > 0.
        - fluid_density : Density of the fluid [kg/m³].
        - reference_viscosity : Reference dynamic viscosity [Pa·s].
        - reference_temperature : Reference temperature [K].

    Returns:
        - The kinematic viscosity of air [m²/s].

    Examples:
        ```py title="Example usage"
        import particula as par
        par.gas.get_kinematic_viscosity_via_system_state(300, 1.2)
        # Output: ~1.5e-5
        ```

    References:
        - "Sutherland's Formula," Wolfram Formula Repository,
          https://resources.wolframcloud.com/FormulaRepository/resources/Sutherlands-Formula
    """
    dynamic_viscosity = get_dynamic_viscosity(
        temperature=temperature,
        reference_viscosity=reference_viscosity,
        reference_temperature=reference_temperature,
    )
    return get_kinematic_viscosity(
        dynamic_viscosity=dynamic_viscosity, fluid_density=fluid_density
    )