Coupled Adjoint Fluid-Structure Interaction Technique for Flexible Wing Shape Optimization

This paper presents the Multi-Disciplinary Optimization (MDO) of a business jet including static aeroelastic effects. Two different CFD tools (AETHER by Dassault Aviation and PUMA by NTUA) are coupled with a CSM model (VPS software by ESI). Single discipline as well as coupled multi-disciplinary sensitivity derivatives (SDs) are computed by means of adjoint methods. Both a purely discrete and a hybrid continuous(fluid)/discrete(structure) adjoint formulations are presented. The computed SDs are verified against finite differences

Aeroacoustic and Aerodynamic Adjoint-Based Shape Optimization of an Axisymmetric Aero-Engine Intake

A continuous adjoint-based aeroacoustic optimization, based on a hybrid model including the Ffowcs Williams–Hawkings (FW–H) acoustic analogy, to account for the multidisciplinary design of aero-engine intakes with an axisymmetric geometry, is presented. To optimize such an intake, the generatrix of its lips is parameterized using B-Splines, and the energy contained in the sound pressure spectrum, at the blade passing frequency at receivers located axisymmetrically around the axis of the engine, is minimized. The engine is not included in the optimization and manifests its presence through an independently computed time-series of static pressure over the annular boundary of the simulation domain that corresponds to the inlet to the fan. Taking advantage of the case axisymmetry, the steady 3D RANS equations are solved in the rotating frame of reference and post-processed to compute the flow quantities’ time-series required by the FW–H analogy. The numerical solution of the unsteady flow equations and the otherwise excessive overall cost of the optimization are, thus, avoided. The objective function gradient is computed using the continuous adjoint method, coupled with the analytical differentiation of the FW–H analogy. The adjoint equations are also solved in the rotating frame via steady solver