Topic: 89th NIA CFD Seminar: Time-dependent Adjoint-based Optimization for Coupled Fluid-Structure Problems
Date: Tuesday, June 27, 2017
Time: 11:00am-noon (EST)
Room: NIA, Rm101
Speaker: Asitav Mishra, Post-Doctoral Scholar, University of Michigan
Abstract: In the recent past, the use of adjoint equations has become a popular approach for solving aerodynamic design optimization problems based on computational fluid dynamics (CFD). While the use of adjoint equations is now fairly well established in steady-state shape optimization, only recently have inroads been made into extending them to unsteady flow problems. This talk presents a formulation for sensitivity analysis of fully coupled time-dependent aeroelastic problems in both hover and forward flight conditions. Sensitivity analysis for forward flight is considered with trim constraints. It includes the effect of blade shape parameters as well as blade cyclic pitch control parameters to enable analysis and optimization of rotors in a trimmed condition. Both forward sensitivity and adjoint sensitivity formulations are derived that correspond to analogues of the fully coupled non-linear aeroelastic analysis problem. Both the sensitivity analysis formulations make use of the same iterative disciplinary solution techniques used for analysis, and make use of an analogous coupling strategy. The information passed between fluid and structural solvers is dimensionally equivalent in all cases, enabling the use of the same data structures for analysis, forward and adjoint problems. Upon successful verification of the fully coupled adjoint formulation, it is used to perform trim and aerodynamic shape design optimization for helicopter rotors in both hover and forward-flight conditions.
Speaker Bio: Asitav Mishra is a post-doctoral scholar in the Department of Aerospace Engineering at the University of Michigan since 2015. Dr. Mishra obtained his Ph.D in Aerospace Engineering from the University of Maryland in 2012. Upon graduation, he held postdoctoral position at the University of Wyoming until 2015. His research interests include adjoint based coupled multi-disciplinary fixed and rotary-wing design optimization, vortex wake-lifting surface interactions as well as performance predictions in rotary wing flows, and data-driven turbulence modeling of vortex dominated flows.