scholarly journals Aerodynamic Shape Design and Validation of an Advanced High-Lift Device for a Regional Aircraft with Morphing Droop Nose

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Alessandro De Gaspari ◽  
Frédéric Moens
Keyword(s):  
Laminar Flow ◽  
Tracking System ◽  
Three Dimensional ◽  
Design Procedure ◽  
Leading Edge ◽  
Optimization Procedure ◽  
Shape Design ◽  
High Lift ◽  
Aerodynamic Shape ◽  
Natural Laminar Flow

In the present work, the aerodynamic shape design of an advanced high-lift system for a natural laminar flow (NLF) wing, based on the combination of a morphing droop nose and a single slot trailing edge flap, is presented. The paper presents both the aerodynamic design and optimization of the NLF wing and the high-lift configuration considering the mutual effects of both flap devices. Concerning the morphing droop nose (DN), after defining the parameterization techniques adopted to describe the geometry in terms of morphing shape and flap settings, the external configuration is obtained by an aerodynamic shape optimization procedure able to meet geometrical constraints and the skin structural requirements due to the morphing. The final performance assessment of the three-dimensional high-lift configurations is performed by high-fidelity aerodynamic analyses. The design procedure is applied to a twin-prop regional aircraft equipped with a natural laminar flow wing. The morphing droop nose is compatible with an NLF wing that requires the continuity of the skin and, at the same time, extends the possibilities to improve the performances of the class of regional aircraft which usually are not equipped with conventional leading edge devices. Additionally, the morphing technology applied to the flap allows the design of a tracking system fully integrated inside the airfoil geometry, leading to a solution without external fairings and so with no extra friction drag penalty for the aircraft.

High-Lift Simulations of Slotted, Natural-Laminar-Flow Airfoils with Drooped Leading Edge

2020 ◽  
Author(s):  
Hector D. Ortiz-Melendez ◽  
Ethan Long ◽  
George Toth ◽  
Kathryn Keely ◽  
James G. Coder
Keyword(s):  
Laminar Flow ◽  
Leading Edge ◽  
High Lift ◽  
Natural Laminar Flow

A Turbofan-Engine Nacelle Shape Design and Optimization Method for Natural Laminar Flow Control

2016 ◽  
Author(s):  
Songyang Li ◽  
Yongjian Zhong
Keyword(s):  
Laminar Flow ◽  
Drag Coefficient ◽  
Longitudinal Profile ◽  
Shape Design ◽  
Aerodynamic Shape ◽  
Optimization System ◽  
Transition Prediction ◽  
Profile Line ◽  
Natural Laminar Flow ◽  
Engine Nacelle

A correctly profiled engine nacelle can delay the transition in the boundary layer and allow laminar flow to extend back, resulting in a substantial drag reduction. Therefore, the laminar flow nacelle has lower fuel consumption than current turbulent designs. In this paper, aerodynamic shape optimization of natural laminar flow nacelle has been studied by using a novel nacelle shape design method and transition prediction with CFD. First, the 2D longitudinal profile-line of nacelle is optimized, in order to extend its laminar region and achieve minimum drag coefficient within the design space. Second, the optimized longitudinal profile-line is then circumferentially stacked to construct the 3D nacelle aerodynamic shape. At last, the aerodynamic improvement of the new shape is evaluated by 3D CFD simulation. A nacelle geometry generator has been developed where the deflection angle (related to the curvature) along the cord is controlled by using Non-Uniform Rational B-Splines. It is then analytically integrated to obtain the longitudinal profile-line. And also a leading edge matching function is involved in the generator. This technique improves the smoothness of nacelle profile-line, which ensures the curvature and slope of curvature to be continuous all over the nacelle surface. The pressure distribution over the nacelle surface has been improved with no spikes in Mach number. A transition model coupling with shear stress transport turbulent model is used in solving Navier-Stokes equations for transition prediction. An optimization system has been established in combination with the geometry generator, the transition prediction model with CFD, a Kriging surrogate model and a Multi-Island Genetic Algorithm. As a result, the aerodynamic improvement, with one profile-line optimized, is obvious against the original nacelle shape by CFD validation in 3D simulation. The optimized nacelle can achieve a laminar flow up to 23% and its drag coefficient has reduced by 6.5%. It is indicated that the optimization system is applicable in nacelle aerodynamic shape design.

A 3D Shape Design and Optimization Method for Natural Laminar Flow Nacelle

2017 ◽  
Author(s):  
Yongjian Zhong ◽  
Songyang Li
Keyword(s):  
Boundary Layer ◽  
Simulated Annealing ◽  
Laminar Flow ◽  
Drag Coefficient ◽  
Frictional Drag ◽  
Initial Shape ◽  
Aerodynamic Shape ◽  
Profile Line ◽  
Adaptive Simulated Annealing ◽  
Natural Laminar Flow

With the rapid development of high bypass ratio turbofan engine, the proportion of the nacelle drag increases obviously in the total drag of the aircraft with the increase of nacelle surface area. And the frictional resistance is one of the major contributors of drag. Under the same Reynolds number, the friction resistance in turbulent boundary layer is about 10 times larger as that in laminar boundary layer. Therefore, a correctly profiled engine nacelle will delay the transition in the boundary layer and allow laminar flow to extend back, resulting in a substantial drag reduction. In the previous conference paper (9th reference), a 2D nacelle longitudinal profile-line geometry generator, which allows curvature and slope-of-curvature to be continuous was developed and presented. This established an optimization system to minimize nacelle frictional drag. One of the nacelle profile-line is optimized to achieve minimum drag coefficient, and then is stacked with the other original profile-lines to form the 3D isolated nacelle aerodynamic shape. Finally, a total 23% of nacelle outer surface maintains a laminar flow and its frictional drag coefficient is less than initial shape. This paper proposes a new 2D nacelle longitudinal profile-line design method, based on PARSEC parameterization, with can generate the profile-line rapidly and precisely. Conservation Full Potential Equation was used to calculate the aerodynamic distribution and obtain the transition location. Then adaptive simulated annealing genetic algorithm was adapted to search 2D profiles of low drag, which would be applied to narrow down design space in 3D nacelle optimization. Second, 2D profiles were stacked circumferentially, by NURBS surface generator, to form the 3D nacelle aerodynamic shape, and an optimization system was established, in combination with the 3D nacelle generator, γ–Reθ transition model, Kriging surrogate model and adaptive simulated annealing algorithm, for natural laminar flow nacelle design. Finally, a total 34% of nacelle surface maintains a laminar flow and its frictional drag coefficient is less than initial shape. The generated optimized loft was evaluated by CFD to determine if the low drag of this optimized nacelle shape can be maintained under different Mach numbers and angles of attack.

Control of Separated Boundary-Layer on Subsonic Airfoil Using Vortex Generator Jet Devices

2006 ◽  
Author(s):  
A. Kourta ◽  
G. Petit ◽  
J. C. Courty ◽  
J. P. Rosenblum
Keyword(s):  
Boundary Layer ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Three Dimensional ◽  
Vortex Generator ◽  
Leading Edge ◽  
Skin Friction Coefficient ◽  
Synthetic Jets ◽  
High Lift ◽  
Longitudinal Vortices

The control of subsonic high lift induced separation on airfoil may improve the flight envelope of current aircraft or even simplify the complex and heavy high-lift devices on commercial airframes. Until now, synthetic jets have proved a really interesting efficiency to delay or remove even leading-edge located separated areas on high-lift configuration but are not efficient for real scale aircrafts. In case of pressure-like separation (i.e. from trailing-edge), synthetic jets can be replaced by so the called “Vortex Generator Jets” which create strong longitudinal vortices that increase mixing in inner boundary layer and consequently the skin friction coefficient is increased to prevent separation. In this study, numerical simulations were undertaken on a generic three dimensional flat plate in order to quantify the effect of the longitudinal vortices on the natural skin friction coefficient. Both counter and co-rotative devices were tested at different exhaust velocities and distances between each others. Finally co-rotative vortex generators jets were tested on a three dimensional generic airfoil ONERA D. Results show a delay of the separation occurence but this solution does not seem to be as robust as synthetic jets. The study of jets spacing with respect to the efficiency of the devices shows a maximum for a given ratio of spacing to exhaust velocity.

scholarly journals High Lift Configuration of a Slotted Natural Laminar Flow Airfoil

2019 ◽  
Author(s):  
Dan Twiss ◽  
Christopher Colletti ◽  
Phillip J. Ansell
Keyword(s):  
Laminar Flow ◽  
High Lift ◽  
Natural Laminar Flow

Parametric Optimization of a High-Lift Turbine Vane

2004 ◽  
Author(s):  
Andrea Arnone ◽  
Duccio Bonaiuti ◽  
Antonio Focacci ◽  
Roberto Pacciani ◽  
Alberto Scotti Del Greco ◽  
...  
Keyword(s):  
Parametric Design ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Design Tool ◽  
Optimization Techniques ◽  
High Lift ◽  
Profile Losses ◽  
Turbine Vane ◽  
Cfd Analyses

Numerical optimization techniques are increasingly used in the aerodynamic design of turbomachine blades. In the present paper, an existing three-dimensional high-lift turbine cascade was redesigned by means of CFD analyses and optimization techniques, based on the blade geometrical parameterization. A new parametric design tool was developed for this purpose. Blade geometry was handled in a fully three dimensional way, using Be´zier curves and surfaces for both camber-surface and thickness distribution. In the optimization procedure different techniques were adopted: a Genetic Algorithm (GA) strategy made it possible to considerably reduce two-dimensional profile losses, while the optimal stacking line was found based on a successive Design of Experiments (DOE) analysis. As a result, a new high-lift blade with higher performance was obtained; in addition, the effect of hub/tip leaning was presented and discussed.

scholarly journals Parametric slat design study for thick base airfoils at high Reynolds numbers

2019 ◽  
Author(s):  
Julia Steiner ◽  
Axelle Viré ◽  
Francesco Benetti ◽  
Nando Timmer ◽  
Richard Dwight
Keyword(s):  
Turbine Blades ◽  
Design Procedure ◽  
Leading Edge ◽  
Optimization Procedure ◽  
Point Of View ◽  
Main Element ◽  
Single Element ◽  
Wind Turbine Blades ◽  
Flow Control Devices ◽  
Stall Angle

Abstract. Standard passive aerodynamic flow control devices such as vortex generators and gurney flaps have a working principle that is well understood. They increase the stall angle and the lift below stall and are mainly applied at the inboard part of wind turbine blades. However, the potential of applying a rigidly fixed leading edge slat element at inboard blade stations is less well understood but has received some attention in the past decade. This solution may offer advantages not only under steady conditions but also under unsteady inflow conditions such as yaw. This article aims at further clarifying what an optimal two-element configuration with a thick main element would look like, and what kind of performance characteristics can be expected from a purely aerodynamic point of view. To accomplish this an aerodynamic shape optimization procedure is used to derive optimal profile designs for different optimization boundary conditions including the optimization of both the slat and the main element. The performance of the optimized designs shows several positive characteristics as compared to single element airfoils, such as a high stall angle, high lift below stall, low roughness sensitivity and higher aerodynamic efficiency. Furthermore, the results highlight the benefits of an integral design procedure, where both slat and main element are optimized, over an auxiliary one. Nevertheless, the designs also have two caveats, namely a steep drop in lift post-stall and high positive pitching moments.

Design Optimization of a Piezocomposite Morphing Multi-Element Airfoil

2020 ◽  
Author(s):  
Cody Wright ◽  
Onur Bilgen
Keyword(s):  
Leading Edge ◽  
Elastic Behavior ◽  
Interaction Method ◽  
Suction Surface ◽  
High Lift ◽  
Structure Interaction ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Fuel Burn ◽  
Natural Laminar Flow

Abstract A slotted natural-laminar-flow airfoil design is a two-element airfoil design that employs a slot between the fore and aft elements. This slot alters the pressure recovery condition on the suction surface of the fore element, minimizing skin-friction and inhibiting the laminar to turbulent transition. These benefits reduce overall aircraft drag and increase wing lift. This allows smaller planforms, in turn, reducing fuel burn. This paper investigates the proposal that by help of piezocomposite surface actuation the aft element can be moved, rotated, and morphed to be used as a high-lift effector for take-off and landing conditions. A theoretical analysis is performed using a coupled fluid-structure interaction method assuming static aero-elastic behavior. During analysis the fore-element of the multi-element airfoil is assumed rigid. Thus, shape optimization is limited exclusively to the aft element. Airfoil morphing is achieved by way of piezocomposite actuating elements applied to the pressure and suction sides of the aft element. A genetic algorithm is used to independently optimize substrate thicknesses for each piezocomposite actuator as well as voltage, chord position and piezocomposite length. The nominal and leading edge substrate thicknesses of the airfoil are also varied. The optimized geometry for the high lift configuration is presented.

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