def calcWaterFractionByVolume(waterVolume, glycerolVolume):
    """
    Calculates the volume fraction of water in a water - glycerol mixture

    Args:
        waterVolume (float): volume of water in l
        glycerolVolume (float): volume of glycerol in l

    Returns:
        :class:`float` Fraction of water by volume in [0, 1]
    """
    gV = float(glycerolVolume)
    wV = float(waterVolume)

    try:
        Cv = wV / (wV + gV)
    except ZeroDivisionError:
        Cv = 0.0

    volumeFractionWater = Cv

    return volumeFractionWater