Continuum Shape Sensitivity For Nonlinear Aeroelastic Gust Response

Abstract

Abstract : The objective of this research was to derive and apply new computational algorithms for the aeroelastic design sensitivity of high fidelity, coupled fluid-structure interaction (FSI) problems. A continuum sensitivity analysis (CSA) method was developed for efficient and accurate computation of shape design derivatives for nonlinear aeroelastic structures. The local and total forms for CSA were compared for the first time, based on their accuracy, efficiency and implementation. A proof was published for equivalence of the total-form CSA method and the discrete analytic method for the first time for general nonlinear transient second-order partial differential equations that govern many field problems. Accuracy of the local-form CSA was increased in two ways. One was to use higher-order p-elements. The other way was to use spatial gradient reconstruction (SGR) of the analysis output to compute the sensitivity boundary conditions. SGR for the structural domain was improved by reconstructing gradients of the Neumann sensitivity boundary conditions directly from force and moment output of the structural analysis instead of reconstructing higher-order derivatives. Guidelines were developed for defining SGR patches with controllable accuracy and rate of convergence for CSA.