Relaxed Fidelity CFD Methods Applied to Store Separation Problems
Abstract
The goal of relaxed fidelity computational fluid dynamics (CFD) methods is to provide a store separation analysis capability that lies between the accuracy-productivity characteristics of influence function methods and time-accurate CFD methods. Two methods are presented in this paper, both of which provide significant accuracy improvements over influence function methods while providing rapid enough turn around times to support parameter and design studies. The first technique discussed is the Minimized Domain CFD (MDCFD) method. This method allows the collection of store force and moment data on relatively small 'minimized' domains that contain the store of interest and any other nearby geometry. The boundary conditions on the minimized domain are extracted from a baseline CFD solution of the full aircraft configuration. The product of the MDCFD method is a set of store force and moment coefficients at various locations relative the aircraft. This method is demonstrated on the Miniature Munition Technology Demonstrator (MMTD) and the Powered Low Cost Autonomous Attack System Tandem Pack Configuration (PLOCAAS) in the flow field of the F/A-22 aircraft. The second technique discussed is the Sensitivity Analysis (SA) method. In this method sensitivity derivatives are computed from a baseline CFD solution on a store using a linearized perturbation scheme and these sensitivity derivatives are added to the baseline solution to obtain the new flow field. The resulting solution costs significantly less to compute than the original baseline solution and allows the efficient computation of a parameter space around a specific baseline solution. The method presented applies perturbation boundary conditions at the surface of the store for variations in store orientation. Predictions are made for a one-degree change in angle of attack and angle of sideslip for the MMTD and PLOCAAS to demonstrate this capability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2004
- Accession Number
- ADA468706
Entities
People
- Dennis Finley
- M. B. Davis
- Rudy Johnson
Organizations
- Air Force Research Laboratory