Fluid-Structure Transient Gust Sensitivity Using Least-Squares Continuous Sensitivity Analysis
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A least-squares continuous sensitivity analysis method is developed for fluid-structure interaction transient gust res ponse problems to support computationally efficient analysis and optimization of aeroelastic design problems. In continuous sensitivity methods, one computes design or shape parameter gradients from the continuous system of partial differential equations instead of the discretized system. The continuous sensitivity equations are a linear boundary-value problem which render computationally efficient design parameter gradients without needing to derive and code the problematic mesh sensitivities of discrete sensitivity methods. The coupled fluid-structure physics and continuous sensitivity system equations for a representative nonlinear gust response problem are posed in first-order form. The boundary conditions for the sensitivity system are derived from a least-squares formulation of the underlying fluid-structure problem. The continuous sensitivity boundary value problem is then solved using a high-order polynomial least-squares finite element model. An important distinction is made between local and total derivatives at material points of the structure and a method for converting the local sensitivities to material derivatives is developed. Continuous sensitivity results for both the local and total material derivatives are presented and compared to gradients obtained by finite-difference methods.
author list (cited authors)
Wickert, D., Canfield, R., & Reddy, J.