PC Desktop Aerodynamic Models for Store Separation from Weapons Bay Cavities and Related Vortical Processes

摘要

Many of the previous investigations of store separation have been confined to external store carriage. Comparatively less attention is being given to separation from cavities and bays. This is probably due to the additional complications related to the interaction of the store with the shear layer as well as the store's coupling with the walls of the cavity. Many large-scale computational simulations have focused on acoustic interactions with the cavity and the associated structural loadings on the fins of the guidance avionics. Many of these large-amplitude oscillations are associated with traveling waves along the shear layer and their interaction with recirculating cavity flow. By contrast to the empty cavity, the filled cavity poses other challenges. The three phases of the motion, above, across, and below the shear layer, involve special combined dynamics and aerodynamic problems. This study provides modeling of three phases of a weapons-bay store release: internal regime in which the store is well within the cavity, transitional regime in which the store is transiting the shear layer, and external flow regime in which the store is outside the cavity but still influenced by it. Combined asymptotics and numerics (CAN) give an insightful picture of shear layer cavities and provide a means of quickly visualizing the flow pattern within them. It appears that the recirculating flow can be modeled with inviscid approximations of the viscous flow for many practical cases. For bodies transiting the shear layer of such cavities, many of the details, such as modification of the apparent mass effect due to the shear layer, can be obtained from cross flow approximation-inner solutions from slender body theory. These tools are now being extended to transonic flows. (15 figures, 7 refs.).