def reynolds(target, u0, b, temperature='pore.temperature'):
    r"""
    Uses exponential model by Reynolds [1] for the temperature dependance of
    shear viscosity

    Parameters
    ----------
    target : OpenPNM Object
        The object for which these values are being calculated.  This
        controls the length of the calculated array, and also provides
        access to other necessary thermofluid properties.

    u0, b : float, array_like
            Coefficients of the viscosity exponential model (mu = u0*Exp(-b*T)
            where T is the temperature in Kelvin

    temperature : string
        The dictionary key containing the temperature values (K).  Can be
        either a pore or throat array.

    [1] Reynolds O. (1886). Phil Trans Royal Soc London, v. 177, p.157.

    """
    value = u0*sp.exp(b*target[temperature])
    return value