def uch_matsen(gs, rhos, ut):
    """
    Choking velocity from the Matsen paper [3]_.

    Parameters
    ----------
    gs : float
        Solids flux [kg/(s m^2)]
    rhos : float
        Density of particle [kg/m^3]
    ut : float
        Terminal velocity [m/s]

    Returns
    -------
    uch : float
        Choking velocity [m/s]

    References
    ----------
    .. [3] Matsen, 1982. Mechanism of Choking and Entrainment. Powder
       Technology, 32, 21-33.
    """
    uch = 10.74 * ut * (gs / rhos)**0.227
    return uch