Computational improvements are critical for the aerospace community to succeed in designing its next generation of high performance vehicles, such as high altitude long endurance Sensorcraft and flapping wing micro air vehicles. A computational method is presented to calculate the sensitivity of a flexible aircraft’s aeroelastic response with respect to changes in shape of the aircraft structure. These gradients facilitate efficient design optimization of high fidelity, physics-based models earlier in the design process, when the most critical design decisions are being made. The continuum sensitivity equations (CSA) approach is to differentiate the partial differential equations that govern the fluid-structure interaction (FSI) to arrive at a system of partial differential sensitivity equations. One first differentiates the FSI boundary conditions to specify the sensitivity boundary conditions. Then, the CSE system may be discretized and solved. The accuracy of this boundary velocity formulation of CSE is ensured by use of high-order p-elements and/or spatial gradient reconstruction. In contrast to the usual discrete sensitivity approach, the principal advantage of CSA is that discrete mesh sensitivity is avoided altogether. Knowledge of the workings of the automatic (or manual) mesh generator is unnecessary and the mesh sensitivity never calculated. Thus, analytic gradients may be computed efficiently with controllable accuracy, treating the analysis solvers as block boxes, much as is done for the popular, but less efficient and less accurate, finite difference approximations. Results are presented for one of the first applications of CSA to fully coupled FSI and the first CSA shape sensitivity calculation of gust response.

Experience

Prof. Canfield’s research interests include structural optimization, multidisciplinary analysis and design methods, including reliability-based design, structural dynamics and controls, and aeroelasticity. He recently received the AIAA Multidisciplinary Design Optimization Award for Technical Excellence. He is a team lead in the Air Force Collaborative Center for Multidisciplinary Sciences at Virginia Tech, where he advises graduate students conducting Air Force (AF) funded research projects. Previously, he worked in research and development for the AF for 24 years. He was on the Air Force Institute of Technology (AFIT) faculty 1993–1996 and 2000–2008. He was the deputy department head of Aeronautics and Astronautics at AFIT from 2002–2004. From 1999–2000 he was the Program Manager for Computational Mathematics at the Air Force Office of Scientific Research (AFOSR).  His program funded basic research in computational fluid dynamics, structural mechanics, plasma physics, combustion and laser chemistry, imaging, quantum computing, and multidisciplinary design. Lt Col Canfield was AFOSR Director of Policy and Integration, 1998–1999, where he directed planning, financial management, support, and administration of the AF $300M basic research program. He also served as the manager for planning and resources for the AF Deputy Assistant Secretary for Science, Technology, and Engineering where he managed the $1.2B AF Science and Technology budget. He became Assistant Head of Aerospace and Ocean Engineering at Virginia Tech in August 2009.