An assessment of pressure variations in artificially ventilated cavities

Abstract

In this work, the character of the pressure within artificially ventilated cavities is investigated in detail using computational fluid dynamics. The efforts explore the details of the pressure inside both twin- and toroidal-vortex cavities through histograms of the internal cavity pressure. Rather than a uniform pressure, detailed interrogation of the pressure indicates a multi-peak distribution of cavity pressure. Further interrogation of these peaks suggests that such pressure variations align with distinct regions within the cavity. Additionally, the character of these distributions are found to be dependent on the cavity closure mode (Campbell and Hilborne, 1958; Karn et al., 2016; Logvinovich, 1972). In evaluating these small, yet present, pressure variations, it is hypothesized that they are the driving force for the internal, re-circulatory flow. Lastly, the importance of these distinct regions of pressure regions is investigated with respect to semi-empirical theory, which aims to directly evaluate the level of validity of the constant pressure assumption. The results indicate that the constant pressure assumption remains valid, but may lead to small inaccuracies when evaluating other cavity characteristics through semi-empirical theory.