Determining the Applicability and Effectiveness of Current CFD Methods in Store Certification Activities

This paper documents results of a ShadowOps project conducted by t he Air Force SEEK EAGLE office at Eglin AFB from August to Sept 2008 in support of the DoD CREATE-AV program. The objective of the project was to determine the applicability and effectiveness of current computational fluid dynamics (CFD) methods in ongoing store certification activities from a stability and control (S&C) perspective. Confirmation that CFD calculations can accurately reproduce experimental data from an S&C perspective is critical to the integration of CFD methods into the S&C flight test, clearance, and certification process of new weapons systems and the broader acquisition process. Current F -16 store certification activities were shadowed by comparing results of a commercial cell-centered, finite volume CFD code, Cobalt, with recently acquired wind tunnel data and data available in the aerodynamic database of Lockheed Martin’s F-16 6-DOF ATLAS. Unstructured grids were created corresponding to critical wind tunnel test configurations. Full and 1/20th scale static steady and unsteady (tim e accurate) simulations at both atmospheric and wind tunnel conditions were performed. Also, CFD rigid body prescribed motion maneuvers were created using flight test data to simulate a select number of actual flight test maneuvers. The main benefits of this effort are: 1) early discovery of complex aerodynamic phenomena that are typically only present in dynamic flight maneuvers and therefore not discovered until flight test, and 2) rapid generation of an accurate aerodynamic model to support aircraft an d weapon certification by reducing required flight test hours and complementing current stability and control testing. The necessity of DoD HPC resources to gather the necessary data in a timely manner in order to support the warfighter is reaffirmed.