Serkan Özgen

A Multi-Fidelity, Multi-Disciplinary Analysis and Optimization Framework for the Design of Morphing UAV Wing

A framework for the design and optimization of a morphing wing is presented. It allows the user to simplify the design process of a morphing UAV wing with a simple and effective interface with the possibility to easily switch between flight phases and morphing concepts. It consists of two main solvers: a high-fidelity CFD module for detailed RANS simulation and a fast low-fidelity module that solves the aeroelastic problem by coupling a geometrically nonlinear structural model to a potential flow aerodynamic model. The structure of the framework and the methodology used for the design of a morphing UAV wing are detailed. This wing is the focus of the European FP7 CHANGE project and serves as an example of the application of this methodology.

Ice Accretion Prediction on Wind Turbines and Consequent Power Losses

Ice accretion on wind turbine blades modifies the sectional profiles and causes alteration in the aerodynamic characteristic of the blades. The objective of this study is to determine performance losses on wind turbines due to the formation of ice in cold climate regions and mountainous areas where wind energy resources are found. In this study, the Blade Element Momentum method is employed together with an ice accretion prediction tool in order to estimate the ice build-up on wind turbine blades and the energy production for iced and clean blades. The predicted ice shapes of the various airfoil profiles are validated with the experimental data and it is shown that the tool developed is promising to be used in the prediction of power production losses of wind turbines.

A Hybrid Morphing Trailing Edge Designed for Camber Change of the Control Surface

In this study, the design and analyses of a novel morphing trailing edge control surface is presented. The developed control surface is intended to be utilized on an Unmanned Aerial Vehicle (UAV). The morphing features of the control surface was obtained by using different compliant materials, which are able to undergo large in-plane deformations. The design also includes the utilization of the composite materials together with conventional aluminum material hence the design is called a hybrid one. The actuation was applied by using various number of small servo actuators located inside the control surface at different locations. During the design, CATIA V5-6R2012 package program was utilized and the structural analyses were conducted with Finite Element Method by using ANSYS® WorkbenchTM v14.0 package program. First, the design and analyses were done for in-vacuo condition and the relevant aerodynamic loading was later considered. The required aerodynamic loads, which were representing the flight conditions of the UAV, were calculated by Computational Fluid Dynamics analyses. The aerodynamic mesh used was generated by Pointwise® V17.2 R2 package program. The SU2 (Stanford University Unstructured) V3.2.1 open source software was also used in the study as the flow solver. The UAV had a baseline wing with NACA6510 airfoil. The required camber and de-camber characteristics were tried to be achieved for various NACA airfoil targets. By conducting a non-linear Finite Element Analysis it was shown that the control surface can successfully undergo both camber and de-camber morphing, both in-vacuo condition and under aerodynamic loading.

Structural and aerodynamic analyses of a hybrid trailing edge control surface of a fully morphing wing

In this article, the design and analysis of a hybrid trailing edge control surface of an unmanned aerial vehicle are presented. The structural design was performed to increase and decrease the camber of the control surface to match selected airfoil profiles. The design was first analyzed with the help of finite element method to assess the morphing capability. The morphed control surface was then analyzed aerodynamically and comparisons with the original target profiles were made. According to the aerodynamic analyses, it was concluded that the control surface can successfully morph into target profiles with very minor changes in the target aerodynamic values while still ensuring the structural integrity and the safety of the control surface.

MDAO for Aerodynamic Assessment of a Morphed Wing for the Loiter Segment of a UAV Flight Mission

In this paper a detailed overview of a framework for an optimization of a morphing wing is presented. The framework presented here aids the design process of a morphing UAV wing which includes the variety of the flight phases and morphing concepts. The framework consists of two main solvers to compute the aerodynamic assessment of the wing: a fast lowfidelity module that solves the aeroelastic problem by coupling a geometrically nonlinear structural model to a potential flow aerodynamic model and a high-fidelity CFD module for detailed RANS simulation. This framework is later applied to the optimization of a morphing UAV wing for the loiter phase of the flight. The wing described in this paper is the focus of the European Union FP7 CHANGE project.

Morphing wing optimization for steady level flight

This paper presents the basic results of the morphing wing planform optimization of an experimental unmanned air vehicle for minimum drag at steady level flight. The aerodynamic design tool that consists of the three-dimensional panel method, two-dimensional boundary layer solution and generalized reduced gradient method-based optimization is appropriate for fixed wing and morphing wing conceptual and preliminary design. The morphing concept is implemented into the solution with the geometric constraints of the wing planform and the airfoil shape design variables. The drag that is created by other components of the aircraft is calculated according to empirical formulas. Wing drag and aircraft drag comparisons between baseline wing (BASE), optimum fixed wing and morphing wing are discussed with the obtained planform and airfoil shapes.

In-Flight Icing Simulations on Airfoils

It is crucial to predict the ice mass, shape and regions of the airframe which are prone to icing in order to design and develop de/anti-icing systems for aircraft and airworthiness certification . In the current study, droplet collection efficiency and ice shape predictions are performed using an originally developed computational tool for a wing tip for which experimental and numerical data are available. Ice accretion modeling consists of four steps in the developed computational tool: flow field solution, droplet trajectory and collection efficiency calculations, thermodynamic analyses and ice growth calculations using the Extended Messinger Model. The models used for these steps are implemented in a FORTRAN code, which is used to analyze ice accretion on 2D geometries including airfoils and axisymmetric inlets. The results are compared with numerical and experimental data available in the literature.

Mathematical Modelling for Wave Drag Optimization and Design of High-Speed Aircrafts

Supersonic flight has been the subject of last half century. Both civil and defence projects have been running to design an aircraft to fly faster than speed of sound. Developing technology and increasing experience of design leads to faster, fuel efficient, hence, ecological, long-ranged aircrafts. These vehicles make people live easy by shortening travel time, perform missions with powerful defence aircrafts and helping explore space. Aerodynamic design is the main argument of the high speed aircrafts improvement. Having less supersonic drag force, which is greater than the double of subsonic case for conventional aircraft, is the ultimate goal of the aircraft designers at supersonic speed. In this chapter, an aerodynamic characteristics of the entire configuration is optimized in order to reach this aim. Moreover, solver algorithm is validated with computational fluid dynamics simulations for different geometries at various speeds. The objective of this study is to develop a program which optimizes wave drag coefficient of high speed aircrafts by numerical methods.