Investigation of fluid mechanics of slotted air-jets for air reverser applications

by E. Lopez and S. Miiftii Northeastern University USA The fluid mechanics of the air flow, caused by a series of irnpioging air-jets, io a constant-height, rigid channel is iovestigated using computational fluid dynamics (CFD). The primary goal of this work is to investigate the effects of the interactions between different air-jets. The model is representative of a cross section of the clearance between a web and an air-reverser. A cross flow is generated by the air trapped io the clearance. Usiog the CFD package Fluent, the effects of channel-height, spaciog between the airjets, supply pressure for the air-jets and number of jets, on the flow characteristics is investigated. In particular a flow "loss" coefficient, defined as the ratio of the velocity obtained usiog average velocity of each jet from the CFD analysis to the velocity obtained from the Bernoulli's equation, was shown to vary from air-jet to air-jet. It was found that a lower channel-clearance increases jet interaction, as it forces jets to flow into each other. Larger spaciog of the air-jets also iocreases jet interaction, as cross flow fully develops iota lateral flow. Supply pressure was seen to have a small effect. The flow "loss" coefficient behavior was characterized as functions of these variables.