Design and Testing of the Common Research Model with Natural Laminar Flow
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Michelle N Lynde↗
Engineering topics
Michelle N Lynde
Publications and source records attributed to Michelle N Lynde.
Design Exploration of a Transonic Cruise Slotted Airfoil
A knowledge-based aerodynamic design method, CDISC, has been leveraged for the computational design exploration of the cruise slotted airfoil as a drag-saving technology for single aisle, transonic transport aircraft. Aerodynamic predictions were generated using the NASA USM3D Reynolds-averaged Navier-Stokes flow solver, and laminar flow assessments were conducted using the NASA BLSTA3D boundary layer profile solver paired with the LASTRAC stability analysis and transition prediction software. The CDISC design method was used to parametrically vary several slotted-airfoil design variables to understand their impact on aerodynamic performance. In addition to establishing best practices for slotted airfoil design, it was observed that the historically noted skin-friction penalty for cruise slotted airfoils was attributed to the low-Reynolds-number boundary layer of the flap. At cruise, this skin-friction penalty negated any potential decrease in pressure drag enabled by the cruise slotted airfoil architecture. This observation led to the development of an Aft-Laminar Multi-element Airfoil concept that uses airfoil shaping to promote natural laminar flow on the flap. At cruise conditions, the concept is predicted to offer a 2.7% reduction in sectional drag relative to a fully turbulent supercritical airfoil. Off-design analyses showed that laminar flow could be maintained with near-cruise variations in angle of attack and Mach number, resulting in sustained aerodynamic efficiency improvements and a delay in the drag rise Mach number. A low-speed, high-lift analysis at takeoff conditions predicted a maximum lift coefficient of 2.4 could be achieved by use of a variable-camber leading edge on the main element and simple deflection of the flap. These computationally-predicted benefits have motivated future research toward an aft-laminar cruise slotted wing design as an incremental step toward the application of natural laminar flow technology on transonic commercial transports.
Brett R Hiller↗
A Design Exploration of Natural Laminar Flow Applications for the SUSAN Electrofan Concept
A trade study supported by the NASA Convergent Aeronautics Solutions (CAS) Project is presently underway to explore the desirability, feasibility, and viability of a new vehicle concept. The vehicle under development is the SUbsonic Single Aft eNgine (SUSAN) Electrofan configuration, which is a subsonic regional jet with the transformative concept of combining wing-mounted distributed electrified aircraft propulsion with a single engine design. The multidisciplinary team is investigating several potential technologies that would help the SUSAN Electrofan configuration achieve its performance goals, one of which is the application of Natural Laminar Flow (NLF) to the main wing. The present computational study utilizes the Crossflow Attenuated Natural Laminar Flow (CATNLF) design method to reshape the wing airfoils to obtain significant extents of NLF at the cruise condition. Fully-turbulent and laminar designs were performed to quantify the aerodynamic performance potential of NLF on the SUSAN Electrofan configuration. The laminar design supported laminar flow on53% of the area of the wing upper surface, resulting in a 19count (8.8%) drag reduction for the wing-fuselage configuration. The near-cruise off-design characteristics are also studied and illustrate that the robust laminar design sustains an NLF performance benefit through perturbations in Mach and angle of attack. A discussion is also included on multidisciplinary implications of utilizing NLF for the configuration, including design, manufacturing, and operational considerations required to support NLF on the main wing, as well as the interaction between the potential wing-mounted boundary layer ingestion technology that is also being explored for the SUSAN Electrofan configuration.
Natural Laminar Flow↗
Update on Subsonic Single Aft Engine (SUSAN) Electrofan Trade Space Exploration
NASA is conducting an ongoing trade study analysis of the SUSAN Electrofan aircraft concept, which utilizes 20-MW-class electrified aircraft propulsion to enable propulsive, aerodynamic, and control benefits while retaining the range, speed, and size of typical narrow-body regional aircraft. The study is constrained by the ground rules of operating within the current airport and airspace infrastructure. This ongoing study seeks to find a configuration and combination of technologies that yield significant fuel burn and emissions benefits. Another key goal is to reduce cost per passenger mile. Currently, the study is focused on a configuration that utilizes jet A or sustainable aviation fuels, however, we plan to consider other fuel alternatives in the future. This paper describes the progress in defining the architecture of the aircraft, engine, power system, control system, and initial understandings of the sensitivity of the potential configurations to technology assumptions based on key performance parameters. Additionally, progress towards definition and refinement of driving operational, economic, infrastructure, certification, and technical requirements is discussed.
aircraft concept↗