def nondimensionalise(rc, qc, rho, x, nature):
    """
    Nondimensionalise a parameter using the characteristic parameters.

    Arguments
    ---------
    rc : float
        Characteristic radius (length)
    qc : float
        Characteristic flow
    rho : float
        Density of blood
    x : float
        Parameter to redimensionalise
    nature : string
        Nature of parameter to be redimensionalised

    Returns
    -------
    return : float
     	Dimensionless quantity
    """
    if nature == 'time':
        x = x*qc/rc**3
    elif nature == 'area':
        x = x/rc**2
    elif nature == 'flow':
        x = x/qc
    elif nature == 'pressure':
        x = x*rc**4/rho/qc**2
    return x