(SYA) 37-1 PC Desktop Aerodynamic Models for Store Separation from Weapons Bay Cavities and Related Vortical Processes

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 such as in store separation, much of the details such as the 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. 1. Need for store separation work Air-launched weapons is an essential military technology that can provide strategic and tactical supremacy. Emphasis on safe, high-accuracy, reliable store separation will be critical for weapon system upgrades to cost-effectively meet threats in a financially austere environment for new aircraft development for the foreseeable future. Although the problem of weapons release from an aircraft platform has received much attention, more effort is needed to understand the underlying basic physics and essential parameters. In a larger sense, this technology is a subset of the problem of the interactions between moving bodies in all speed ranges. Applications include separation and carriage of various stage vehicles for space missions and flight testing as well as crew escape. For this group, hypersonic multistage vehicle concepts of interest to the U.S. Air Force frequently utilize the launch of a small rocket-powered stage from a large subsonic or transonic aircraft such as the B-52. Other examples are the PEGASUS series and the Shuttle. Currently, multistage launch scenarios are envisioned for future hypersonic and space applications. A new thrust involves the use of airbreathing (scramjet or turbo-scramjet) rather than rocket-powered stages. 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 and the store as well as the coupling with the walls of the Paper presented at the RTO AVT Symposium on “Advanced Flow Management: Part A – Vortex Flows and High Angle of Attack for Military Vehicles”, held in Loen, Norway, 7-11 May 2001, and published in RTO-MP-069(I). Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 00 MAR 2003 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE PC Desktop Aerodynamics Models for Store Separation from Weapons Bay Cavities and Related Vortical Processes 5a. CONTRACT NUMBER