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ROI 2009-0501-1167
The Next Decade in CommercialAircraft AerodynamicsAircraft Aerodynamics –
The next decade in commercial airplane aerodynamics – a Boeing perspective
commercial jet age at BoeingB i 367 80 ( i 1954)Boeing 367-80 (circa 1954) Prototype for KC-135, B707 family Boeing’s first low-swept-wing transport Configuration basis for the future: Wing-mounted pod engines Double-slotted Fowler flaps with LE Krueger flaps
The next decade in commercial airplane aerodynamics – a Boeing perspective
Other configurations
Wing-mounted pod engines were not always selected Aft-mount allows lower-to-the-ground configuration Perhaps more efficient with then-current technology Odd number of engines (3)
The next decade in commercial airplane aerodynamics – a Boeing perspective
benefits and issues
Natural Laminar Flow (NLF) and Hybrid Laminar Flow Control (HLFC) demonstrated in aerodynamic flight tests Transition flow physics generally understoodTransition flow physics generally understood Scale and sweep affect laminar-flow application (NLF vs. HLFC) Continuous progress in analysis and design methods
Laminar flow reduces fuel burn, emissions and noise Benefit depends on scale of application Improved fuel burn allows smaller lighter quieter aircraft Improved fuel burn allows smaller, lighter, quieter aircraft Estimated net potential fuel burn benefit for subsonic transports ~ 5 – 12 %
L i fl li ti i Laminar flow application issues Manufacturing, certification, and operational requirements and impacts Drag benefit needs to be traded against increased weight, maintenance, cost,
The next decade in commercial airplane aerodynamics – a Boeing perspective
p ( )Committed to 787 in 2005
Nacelle contours optimized with laminar transition location as additional design parameter Structural design and manufacturing methods tailored for NLF benefit
The next decade in commercial airplane aerodynamics – a Boeing perspective
benefits and issues
Riblet technology has been demonstrated to passively reduce local turbulent skin friction ~6 % Tunnel and flight tests with riblet films conductedTunnel and flight tests with riblet films conducted Application constraints (shape, spacing, streamlining) are
understood
Ribl li i i d i`
Riblet application issues are not aerodynamic: Limited riblet shape and adhesive robustness over
operational life (hydraulic liquids, hail, dirt and impact) Appearance relative to standard paint and livery Appearance relative to standard paint and livery Time required to install, maintain, remove and re-apply
The next decade in commercial airplane aerodynamics – a Boeing perspective
Active Flow Control (AFC)
AFCAFC
Example: Application concept study with AFC augmented wing high lift system(Reference NASA CR-1999-209338)
High lift configurationwith AFC actuators
AFC
Evaluating Active-Flow Control (AFC) actuator and integration concepts for simplified (lighter) systems with similar performance as traditional mechanical high-lift elements ( g te ) syste s t s a pe o a ce as t ad t o a ec a ca g t e e e ts Robust, reliable and low-maintenance AFC actuation to be developed and
demonstrated for commercial transport Key issues that affect application success for commercial aircraft are:Key issues that affect application success for commercial aircraft are: Actuator capability, robustness and noise System power, complexity and cost Failure modes and redundancy considerations
The next decade in commercial airplane aerodynamics – a Boeing perspective
Computational Fluid Dynamics (CFD)
Faster, more capable, and less costly computing hardware Faster and better algorithms Higher fidelity flow physics modeledHigher fidelity flow physics modeled Expanding simulations towards edges of flight envelope Integration with structural and systems modeling (MDO) Integration with wind tunnel and flight testingIntegration with wind tunnel and flight testing
Availability – ready and available when needed Cost efficiency – good value for the money
The next decade in commercial airplane aerodynamics – a Boeing perspective
Types of wind tunnel testing
Configuration development testing Incremental and absolute aerodynamic coefficient data Cruise, high-lift, and flight envelope limit data Airframe noise Propulsion installation Tare and interference testing
Fl t l t Flow control concepts Alternate configurations will require significant additional testing
Database development testingAi l f Airplane performance
Stability and control including simulator database Aerodynamic loads throughout envelope
Specialized testing Specialized testing Full scale Reynolds number Thrust reversers Ground effect
The next decade in commercial airplane aerodynamics – a Boeing perspective
Flight testing aerodynamic technologies
Flight testing for certificationFlight testing for development/evaluation of aerodynamic
technologiestechnologies Certain technologies are difficult to simulate on scaled models in tunnel Concept to be flight tested must integrate with test vehicle
Fli ht t ti t id ti l i Flight testing to provide operational experience
The next decade in commercial airplane aerodynamics – a Boeing perspective
Summary
Aerodynamics will be key contributor to the future of aircraft design Safety Efficiency Environmental compatibility
The next decade of challenges will be multidisciplinary New aerodynamic technologies are on the horizon Integration with structures, propulsion, and systems, enabled by further computationalIntegration with structures, propulsion, and systems, enabled by further computational
advances Manufacturability and maintainability to introduce flow control methods
Aerodynamic technologies, together with tools, processes, and people, will be keys to future advances