26 Progress in Computational Fluid Dynamics, Vol. 16, No. 1, 2016 Aeroelastic predictions for steady and unsteady flow characteristics of the HIRENASD wing Melike Nikbay* and Pınar Acar Department of Astronautical Engineering, Faculty of Aeronautics and Astronautics, Istanbul Technical University, Maslak, Istanbul, 34469, Turkey Email: nikbay@itu.edu.tr Email: acarpin@itu.edu.tr *Corresponding author Abstract: In this study, we focus on static and dynamic aeroelastic analyses of the HIRENASD wing based on reference experimental data for two different flight conditions for Aeroelastic Prediction Workshop-1. The major anticipations from the HIRENASD project are to improve the knowledge about aero-structural dynamics, and to get experimental and computational data in a wide range of flight conditions. The experiments have been formerly conducted in cryogenic medium to investigate steady and unsteady aeroelastic responses in transonic regime for low and high Reynolds numbers. For current aeroelastic computations, first, a free vibration analysis is performed in Nastran using the latest structural model provided by NASA. Sequentially, the modal solution is imported from the finite element solver to Zeus software which is an Euler equations based aeroelastic solver coupled with integral boundary layer method. The aerodynamic model and fluid structure interaction parameters are constructed in Zeus. Steady and unsteady aeroelastic results are examined for the specified stations along the wing span, and interpolated for chordwise direction so as to match them with the wind tunnel test points. The designated output parameters such as steady aerodynamic lift, moment and drag coefficients, and steady and unsteady pressure distributions along the chordwise direction are compared to the experimental data and NASA’s FUN3D code results which are provided in literature. Keywords: aeroelasticity; HIRENASD; aeroelastic prediction; unsteady flow; fluid-structure interaction; wind tunnel test; computational aeroelasticity; computational fluid dynamics; modal analysis; Euler equations. Reference to this paper should be made as follows: Nikbay, M. and Acar, P. (2016) ‘Aeroelastic predictions for steady and unsteady flow characteristics of the HIRENASD wing’, Progress in Computational Fluid Dynamics, Vol. 16, No. 1, pp.26–37. Biographical notes: Melike Nikbay got her BS and MS in Mechanical Engineering from Bogazici University in Turkey. She got her MS and PhD in Aerospace Engineering from University of Colorado at Boulder in USA. She is an Associate Professor of Aerospace Engineering at Istanbul Technical University. Her current research interests are multidisciplinary analysis and optimisation, aeroelasticity, fluid-structure interaction and design under uncertainty. Pınar Acar obtained her BS in Astronautical Engineering, MS in Aeronautical and Astronautical Engineering from Istanbul Technical University in Turkey. Her research interests are analytical and computational aeroelasticity, aeroservoelasticity, aeroelastic optimisation and applied mathematics. This paper is a revised and expanded version of a paper entitled ‘Steady and unsteady aeroelastic computations of HIRENASD wing for low and high Reynolds numbers’ presented at 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Boston, Massachusetts, USA, 8–11 April 2013. 1 Introduction Aeroelasticity, as a multidisciplinary research field, investigates the behaviour of an elastic structure in airstream and interaction of inertial, aerodynamic and structural forces. With the use of advanced technologies in aircraft design, the need in predicting such aero-structure interactions by using high-fidelity computational models has increased. For aeroelastic modelling, computational fluid dynamics (CFD) and computational structural Copyright © 2016 Inderscience Enterprises Ltd.