Numerical Simulation of Wake Deflection Control around NACA0012 Airfoil Using Active Morphing Flaps

This study demonstrates an active flow control for deflecting a direction of wake vortex structures behind a NACA0012 airfoil using an active morphing flap. Two-dimensional direct numerical simulations are performed for flows at the chord Reynolds number of 10,000, and the vortex pattern in the controlled and noncontrolled wakes as well as the effect of an actuation frequency on the control ability are rigorously investigated. It is found that there is an optimum actuation-frequency regime at around F + = 2.00 which is normalized by the chord length and freestream velocity. The wake vortex pattern of the well-controlled case is classified as the 2P wake pattern according to the Williamson’s categorization [1] [2], where the forced oscillation frequency corresponds to the natural vortex shedding frequency without control. The present classification of wake vortex patterns and finding of the optimum frequency regime in the wake deflection control can lead to a more robust design suitable for vortex-induced-vibration (VIV) related engineering systems.

Seamless morphing trailing edge flaps for UAS-S45 using high-fidelity aerodynamic optimization

The seamless trailing edge morphing flap is investigated using a high-fidelity steady-state aerodynamic shape optimization to determine its optimum configuration for different flight conditions,including climb,cruise,and gliding descent.A comparative study is also conducted between a wing equipped with morphing flap and a wing with conventional hinged flap.The optimization is performed by specifying a certain objective function and the flight performance goal for each flight condition.Increasing the climb rate,extending the flight range and endurance in cruise,and decreasing the descend rate,are the flight performance goals covered in this study.Various optimum configurations were found for the morphing wing by determining the optimum morphing flap deflection for each flight condition,based on its objective function,each of which performed better than that of the baseline wing.It was shown that by using optimum configuration for the morphing wing in climb condition,the required power could be reduced by up to 3.8%and climb rate increases by 6.13%.The comparative study also revealed that the morphing wing enhances aerodynamic efficiency by up to 17.8%and extends the laminar flow.Finally,the optimum configuration for the gliding descent brought about a 43%reduction in the descent rate.

Morphing wing flaps for large civil aircraft:Evolution of a smart technology across the Clean Sky program

Abstract Morphing wing structures are widely considered among the most promising technologies for the improvement of aerodynamic performances in large civil aircraft.The controlled adaptation of the wing shape to external operative conditions naturally enables the maximization of aircraft aerodynamic efficiency,with positive fallouts on the amount of fuel burned and pollutant emissions.The benefits brought by morphing wings at aircraft level are accompanied by the criticalities of the enabling technologies,mainly involving weight penalties,overconsumption of electrical power,and safety issues.The attempt to solve such criticalities passes through the development of novel design approaches,ensuring the consolidation of reliable structural solutions that are adequately mature for certification and in-flight operations.In this work,the development phases of a multimodal camber morphing wing flap,tailored for large civil aircraft applications,are outlined with specific reference to the activities addressed by the author in the framework of the Clean Sky program.The flap is morphed according to target shapes depending on aircraft flight conditions and defined to enhance high-lift performances during takeoff and landing,as well as wing aerodynamic efficiency during cruise.An innovative system based on finger-like robotic ribs driven by electromechanical actuators is proposed as morphing-enabling technology;the maturation process of the device is then traced from the proof of concept to the consolidation of a true-scale demonstrator for pre-flight ground validation tests.A step-by-step approach involving the design and testing of intermediate demonstrators is then carried out to show the compliance of the adaptive system with industrial standards and safety requirements.The technical issues encountered during the development of each intermediate demonstrator are critically analyzed,and justifications are provided for all the adopted engineering solutions.Finally,the layout of the true-scale demonstrator is presented,with emphasis on the architectural strengths,enabling the forthcoming validation in real operative conditions.

Design of a large-scale model for wind tunnel test of a multiadaptive flap concept

The design and application of morphing systems are ongoing issues compelling the aviation industry.The Clean Sky-program represents the most significant aeronautical research ever launched in Europe on advanced technologies for greening next-generation aircraft.The primary purpose of the program is to develop new concepts aimed at decreasing the effects of aviation on the environment,increasing reliability,and promoting eco-friendly mobility.These ambitions are pursued through research on enabling technologies fostering noise and gas emissions reduction,mainly by improving aircraft aerodynamic performances.Within the Clean Sky framework,a multimodal morphing flap device was designed based on tight industrial requirements and tailored for large civil aircraft applications.The flap is deployed in one unique setting,and its cross section is morphed differently in take-off and landing to get the necessary extra lift for the specific flight phase.Moreover,during the cruise,the tip of the flap is deflected for load control and induced drag reduction.Before manufacturing the first flap prototype,a high-speed(Ma=0.3),large-scale test campaign(geometric scale factor 1:3)was deemed necessary to validate the performance improvements brought by this novel system at the aircraft level.On the other hand,the geometrical scaling of the flap prototype was considered impracticable due to the unscalability of the embedded mechanisms and actuators for shape transition.Therefore,a new architecture was conceived for the flap model to comply with the scaled dimensions requirements,withstand the relevant loads expected during the wind tunnel tests and emulate the shape transition capabilities of the true-scale flap.Simplified strategies were developed to effectively morph the model during wind tunnel tests while ensuring the robustness of each morphed configuration and maintaining adequate stiffness levels to prevent undesirable deviations from the intended aerodynamic shapes.Additionally,a simplified design was conceived for the flap-wing interface,allowing for quick adjustments of the flap setting and enabling load transmission paths like those arising between the full-scale flap and the wing.The design process followed for the definition of this challenging wind tunnel model has been addressed in this work,covering the definition of the conceptual layout,the numerical evaluation of the most severe loads expected during the test,and the verification of the structural layout by means of advanced finite element analyses.