Abstract
This paper describes the applicability of Boussinesq equation to air cavity advancing into a closed conduit filled with water. Hosoda et al. previously proposed the numerical method to track an interface between pressurized flow and free surface flow, using both the hydrostatic momentum equation and Boussinesq equation. But, the applicability of two models is not clear in view of the reproduction of air-cavity profile and free surface profile near an air cavity. In this study, numerical simulations were conducted under the conditions of previous experiments including free over flow, lock exchange flow and controlled buoyancy flux cases to identify the proper setting of computational methods related to the front speed of air-cavity, pressure drop near the cavity front, etc. It is pointed out that simulated air-cavity profiles obtained using Boussinesq eq. are in good agreement with experiments for all cases if the proper computational methods are used. It is also pointed out that the solitary wave solution is compatible with air-cavity profile of experiments.
