Acfd Applications to Store Separation – Status Report

During the past decade, the Navy has considerably improved its capabilities in aircraft/weapon integration. In 1989 it took more than 400 hours of wind tunnel testing, which cost 1,5000,000, and 20 flights to clear the JSOW from the F-18 to Mach 0.95. This year the MK-83 JDAM was cleared after only 60 hours of wind tunnel testing and five flights to the full F-18 aircraft envelope of Mach 1.3. This reduction occurred because the Navy not only learned to test smarter, but also developed an integrated approach to Modeling & Simulation (M&S), wind tunnel and flight testing which allowed lessons learned on previous programs to be applied to new ones. However, the present approach still requires a fairly large commitment of time and financial resources to accomplish the mission. The present approach has optimized the use of available resources; any further gains will have to come not by improving existing techniques, but by bringing new resources into the process. Several years ago the Office of the Secretary of Defense (OSD), under the Central Test and Evaluation Investment Program (CTEIP) funded a tri-service research project termed Applied Computational Fluid Dynamics (ACFD) for store separation. This project is meant to provide analysis tools that effectively use Computational Fluid Dynamics (CFD) for store certification analysis. ACFD will provide the needed tools that will reduce DOD dependence on wind tunnel and flight-testing. ACFD is not intended to replace the wind tunnel in the near future; rather it will be used to determine the critical regions of the flight envelope to help structure the wind tunnel test, and to explain any wind tunnel anomalies and help structure the flight test program. The objective of the program is to provide upgraded analysis tools that will support store certification requirements at less cost and in less time.