A new non-linear vortex lattice method: Applications to wing aerodynamic optimizations

Gabor, Oliviu Şugar; Koreanschi, Andreea; Botez, Ruxandra Mihaela

doi:10.1016/j.cja.2016.08.001

Cited by 57 publications

(16 citation statements)

References 32 publications

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“…Like the non-linear LLT method presented in the previous section, the predictive capabilities of the VLM can be enhanced by introducing, to a limited extent, viscous effects (23,24) . For each vortex ring, a correction is defined, so that the final values of the vortex intensities become…”

Section: Non-linear Vortex Lattice Methodsmentioning

confidence: 99%

Fast and accurate quasi-3D aerodynamic methods for aircraft conceptual design studies

Gabor

Koreanschi

2020

Aeronaut. j.

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In this paper, recent developments in quasi-3D aerodynamic methods are presented. At their core, these methods are based on the lifting-line theory and vortex lattice method, but with a relaxed set of hypotheses, while also considering the effect of viscosity (to a certain degree) by introducing a strong non-linear coupling with two-dimensional viscous aerofoil aerodynamics. These methods can provide more accurate results compared with their inviscid classical counterparts and have an extended range of applicability with respect to the lifting surface geometry. Verification results are presented for both steady-state and unsteady flows, as well as case studies related to their integration into aerodynamic shape optimisation tools. The good accuracy achieved using relatively low computational time makes such quasi-3D methods a solid choice for conducting conceptual-level design and optimisation of lifting surfaces.

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Section: Non-linear Vortex Lattice Methodsmentioning

confidence: 99%

Fast and accurate quasi-3D aerodynamic methods for aircraft conceptual design studies

Gabor

Koreanschi

2020

Aeronaut. j.

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“…An alternative approach to LLT that addresses the viscosity and thickness effects limitations is to couple the 3D lift distribution from LLT to 2D airfoil data that can be obtained from either experiments [38,39] or a 2D-airfoil analysis tool [40], followed by iterating the 2D and 3D solutions until certain convergence criterion is met. Anderson et al successfully implemented this technique for modeling the stall behavior of finite wing with drooped leading edge [39].…”

Section: A Aerodynamic Modelmentioning

confidence: 99%

“…Furthermore, Şugar-Gabor et al implemented both LLT [41] and VLM [40] routines using XFOIL as twodimensional flow solver. Their LLT was validated against CFD for Mach numbers between M = 0.05 and M = 0.2 and angles of attack between α = −2 and α = +8 • .…”

Section: A Aerodynamic Modelmentioning

confidence: 99%

“…They observed good agreement between CFD and LLT lift and pitch moment coefficients, however, drag coefficients start to diverge at angles of attack greater than α = 4 • . Also, they suggested in their VLM study that drag accuracy could be improved by introducing experimental results to the VLM+XFOIL algorithm [40]. Additionally, they tested their model to study the aerodynamics of a morphing wing, and were successfully able to quantify the aerodynamic performance gains of their morphing concept.…”

Section: A Aerodynamic Modelmentioning

confidence: 99%

“…where f mn are known as the influence coefficients [40,43]. The calculated vortex strengths can then be used to calculate the lift-per-unit span at each horseshoe element by using Kutta-Joukowski theorem.…”

Section: Fig 4 Diagram Of a Horseshoe Element With Its Respective Pomentioning

confidence: 99%

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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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Robust optimal transition maneuvers control for tail‐sitter unmanned aerial vehicles

Yang

Wang

et al. 2021

Intl J Robust & Nonlinear

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Optimal transition has been widely studied for tail‐sitter unmanned aerial vehicles (UAVs). However, since the derived optimal control can only be applied in an open‐loop form, unmodeled dynamics and external disturbances cannot be restrained. Aiming at this problem, this article presents a method to obtain optimal transition maneuvers in the presence of these uncertainties. The approach includes two steps: nonlinear trajectory optimization and robust trajectory tracking. For the trajectory optimization, the minimum altitude variation front and back transition trajectories are derived. Different from existing optimal transition studies, considerable actuator margins are reserved in this step. Thus the tail‐sitter possesses control efforts to perform closed‐loop corrections for uncertainties. For the trajectory tracking, a robust controller in the form of feedforward plus feedback is proposed. The feedforward term directly employs the derived optimal control to improve the dynamic response of the system. The feedback term adopts linear control and acceleration‐based compensator to place desired poles and restrain all uncertainties. To the authors' knowledge, this article is the first time to study the tail‐sitter robust transition control method considering the transition optimality and actuator margins. It is proved that the tracking errors converge into a specified neighborhood of the origin in a finite time. Simulation studies corroborate the performance of the optimal transition trajectories and the robust trajectory tracking controller.

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A new non-linear vortex lattice method: Applications to wing aerodynamic optimizations

Cited by 57 publications

References 32 publications

Fast and accurate quasi-3D aerodynamic methods for aircraft conceptual design studies

Fast and accurate quasi-3D aerodynamic methods for aircraft conceptual design studies

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

Robust optimal transition maneuvers control for tail‐sitter unmanned aerial vehicles

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