Weissinger's model of the nonlinear lifting-line method for aircraft design

Owens, D. Bruce

doi:10.2514/6.1998-597

Cited by 31 publications

(16 citation statements)

References 3 publications

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“…They are suitable for incorporation in flight dynamics simulations. In fact, Bunge and Kroo have recently demonstrated the use of a VLM, formulated in a compact form, in real-time simulation for pre-stall flight [4].For several decades, researchers have sought to extend these linear prediction methods to handle the aerodynamic analysis of wings in which nonlinear airfoil lift curves extending to stall or poststall are used as inputs [5][6][7][8][9][10][11][12][13][14][15][16]. The motivation is that it is significantly easier to obtain aerodynamic characteristics for airfoils than for wings and configurations, whether by using CFD or experiment or by drawing on existing databases.…”

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confidence: 99%

Iteration schemes for rapid post‐stall aerodynamic prediction of wings using a decambering approach

Paul

Gopalarathnam

2014

Numerical Methods in Fluids

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SUMMARYNonlinear aerodynamics of wings may be evaluated using an iterative decambering approach. In this approach, the effect of flow separation due to stall at any wing section is modeled as an effective reduction in section camber. The approach uses a wing analysis method for potential‐flow calculations and viscous airfoil lift curves for the sections as input. The calculation procedure is implemented using a Newton–Raphson iteration to simultaneously satisfy the boundary condition, which comes from potential‐flow wing theory, and drive the sectional operating points toward their respective viscous lift curves, as required for convergence. Of particular interest in this research is the calculation of the residuals during the Newton iteration. Unlike a typical implementation of the Newton iteration, the residual calculation is not performed via a straightforward function evaluation, but rather by estimating the target operating points on the input viscous lift curves. Estimation of these target operating points depends on the assumptions made in the cross‐coupling of the decambering at the different sections. This paper presents four residual calculation schemes for the decambering approach. The residual calculation schemes are compared against each other to assess computational speed and robustness. Decambering results are also compared with higher‐order computational fluid dynamics (CFD) solutions for rectangular and swept wings. Results from the best scheme compare well with the CFD solutions for the rectangular wing, motivating further development of the method. Poor predictions for the swept wings are traced to spanwise propagation of separated flow at stall, highlighting the limitations of the current approach. Copyright © 2014 John Wiley & Sons, Ltd.

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confidence: 99%

Iteration schemes for rapid post‐stall aerodynamic prediction of wings using a decambering approach

Paul

Gopalarathnam

2014

Numerical Methods in Fluids

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“…The use of a fixed relaxation factor is introduced to assist convergence. Previous studies have determined a value of DF = 0.05 is sufficient to assist convergence [37,39], however, these studies noted that this relaxation factor is highly dependant on the specific geometry and operating condition. Due to large changes in camber in this application, it was observed that additional damping was needed to assist convergence.…”

Section: Nonlinear Lifting-line Solutionmentioning

confidence: 97%

“…Although panel methods are significantly more efficient than CFD, it is difficult to incorporate viscosity effects into them, and viscous effects are an important contributor to the overall drag. Another option is to use numerical methods that are based on Prandlt's Lifting-Line Theory, such as Vortex Lattice Method (VLM) [36] and its precursor, Weissinger Lifting-Line Theory (LLT) [37]. These two techniques implement finite vortex filaments to calculate lift and induced drag.…”

Section: A Aerodynamic Modelmentioning

confidence: 99%

Numerically Efficient Three-Dimensional Fluid-Structure Interaction Analysis for Composite Camber Morphing Aerostructures

Rivero¹,

Cooper²,

Woods

2020

AIAA Scitech 2020 Forum

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This paper presents a newly developed three-dimensional Fluid-Structure Interaction (FSI) routine for the Fish Bone Active Camber (FishBAC) concept that couples a three-dimensional Lifting-Line theory analysis to a two-dimensional viscous corrected panel method (XFOIL) to create a viscous corrected three-dimensional wing aerodynamic solver. This aerodynamic model is then coupled to a previously developed multi-component Mindlin-Reissner plate model based composite analysis routine for the FishBAC morphing device. The methodology is explained, and predictions are validated against existing modeling tools. The FSI model developed in this paper shows good agreement when compared against other structural, aerodynamic and FSI tools. Additionally, results show the FishBAC's ability to improve aerodynamic performance at a wide range of operating conditions.

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“…Currently, the lowest level of fidelity in the aerodynamics module is the fidelity zero methods which uses a vortex lattice 6 for the prediction of lift and the correlations for the prediction of drag for the subsonic case. Lift SUAVE has capabilities for both subsonic and supersonic lift.…”

Section: Fidelity Zeromentioning

confidence: 99%

SUAVE: An Open-Source Environment for Multi-Fidelity Conceptual Vehicle Design

Lukaczyk

Wendor

Botero

et al. 2015

16th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference

121

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SUAVE, a conceptual level aircraft design environment, incorporates multiple information sources to analyze unconventional configurations. Developing the capability of producing credible conceptual level design conclusions for futuristic aircraft with advanced technologies is a primary directive. Many software tools for aircraft conceptual design rely upon empirical correlations and other handbook approximations. SUAVE proposes a way to design aircraft featuring advanced technologies by augmenting relevant correlations with physics-based methods. SUAVE is constructed as a modular set of analysis tools written compactly and evaluated with minimal programming effort. Additional capabilities can be incorporated using extensible interfaces and prototyped with a top-level script. The flexibility of the environment allows the creation of arbitrary mission profiles, unconventional propulsion networks, and right-fidelity at right-time discipline analyses. This article will first explain how SUAVE's analysis capabilities are organized to enable flexibility. Then, it will summarize the analysis strategies for the various disciplines required to evaluate a mission. Of particular interest will be the construction of unconventional energy networks necessary to evaluate configurations such as hybrid-electric commercial transports and solar-electric unmanned aerial vehicles (UAVs). Finally, verification and validation studies will be presented to demonstrate the capabilities of SUAVE, including cases for conventional and unconventional vehicles. While some of these cases will be optimized results, discussion of SUAVE's interface with optimization will be reserved for a future publication.

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Weissinger's model of the nonlinear lifting-line method for aircraft design

Cited by 31 publications

References 3 publications

Iteration schemes for rapid post‐stall aerodynamic prediction of wings using a decambering approach

Iteration schemes for rapid post‐stall aerodynamic prediction of wings using a decambering approach

Numerically Efficient Three-Dimensional Fluid-Structure Interaction Analysis for Composite Camber Morphing Aerostructures

SUAVE: An Open-Source Environment for Multi-Fidelity Conceptual Vehicle Design

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