Aerodynamic Design of Transonic Natural-Laminar-Flow (NLF) Wing via Surrogate-basedGlobal Optimization

2016 ◽  
Author(s):  
Zhong-Hua Han ◽  
Jing Chen ◽  
Zhen Zhu ◽  
Wen-Ping Song
Keyword(s):  
Laminar Flow ◽  
Aerodynamic Design ◽  
Natural Laminar Flow

scholarly journals The Objective Space and the Formulation of Design Requirement in Natural Laminar Flow Optimization

2020 ◽  
Vol 10 (17) ◽  
pp. 5943 ◽  
Author(s):  
Shuyue Wang ◽  
Cong Wang ◽  
Gang Sun
Keyword(s):  
Laminar Flow ◽  
Design Space ◽  
Principal Component ◽  
Aerodynamic Design ◽  
Design Requirement ◽  
Pressure Drag ◽  
Design Variables ◽  
Objective Space ◽  
Natural Laminar Flow ◽  
The Impact

Design requirement is as important in aerodynamic design as in other industries because it sets up the objective for the samples in design space to approach. Natural Laminar Flow (NLF) optimization belongs to the type of aerodynamic design problems featured by the combination of distinct aerodynamic performance, where the design requirement is often formulated in form of summation of laminar-related performance and pressure drag performance with different weight assignment according to different perspectives. However, the formulations are rather experience-oriented and are decided non-quantitatively. Inspired by data manipulation approaches in design space (spanned by design variables of geometrical representation parameters) in many aerodynamic designs, this paper proposes new formulations of design requirement in NLF optimization via consideration of objective space (projection of design space through aerodynamics) and shows the impact of the corresponding formulation of design requirement to the result of NLF optimization in cases of transonic airfoil and aero engine compressor blade design from two perspectives: Pareto front convergence and improving effect of accessory performance. The paper uses Principal Component Analysis (PCA) to obtain the eigenvectors of objective space to extract the intrinsic information about specific problem. The method is realized in two cases with satisfactory result.

Dynamic Stall over a Pitching Natural-Laminar-Flow Airfoil

AIAA Journal ◽  
2021 ◽  
pp. 1-12
Author(s):  
Patrick R. Hammer ◽  
Daniel J. Garmann ◽  
Miguel R. Visbal
Keyword(s):  
Laminar Flow ◽  
Dynamic Stall ◽  
Natural Laminar Flow

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.

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