This paper, building on a series of previous articles on the slit models, provides a new mechanistic film model for the description of trickle-bed reactor hydrodynamic parameters (two-phase pressure drop, total external liquid holdup) in the low interaction regime. An important feature of the model is a more physical assumption of continuity in the velocity and shear stress profiles at the gas-liquid interface. The model also introduces a concept borrowed from the modeling of falling-film reactors, in which the degree of interaction between fluids is described by incorporating a phenomenological gas-liquid interaction factor psi(gl). This interaction factor has been extracted by solving an inverse formulation of the film model over a comprehensive database consisting of ca. 5000 pressure gradient and liquid holdup measurements. It was thereafter correlated through artificial neural networks and dimensional analysis to the input characteristics of the trickle-bed reactor. Including the resulting correlation [psi(gl) = psi(gl) (Re-gl, We(l), Fr-l, St(l), Ga-l, Ga-g, X-l, S-b)] in the film model yielded mean absolute relative errors of 18.1% for the total pressure drop and 18.5% for the liquid holdup. Finally, parametric simulations of the behavior of psi(gl) as a function of the various trickle-bed operating variables confirmed the physical coherence of the proposed interfacial interaction factor.