Further Refinement of the Subsonic Doublet-Lattice Method

Rodden, William P.; Taylor, Paul F.; Mcintosh, S. C.

doi:10.2514/2.2382

Cited by 105 publications

(79 citation statements)

References 6 publications

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“…In the DLM framework, a lifting surface is discretized in a number of panels, and the following algebraic system of equations has to be solved: (15) where N AP indicates the total number of aerodynamic panels and D ij is the normal wash factor. In this paper, D ij was calculated by exploiting Rodden's quartic DLM [6]. For the sake of brevity, the procedure to compute the normalwash factor is not reported here, but it can be found in Rodden's paper.…”

Section: Aeroelastic Formulation: Doublet Lattice Methods and Mesh-to-mentioning

confidence: 99%

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Advanced 1D Structural Models for Flutter Analysis of Lifting Surfaces

Petrolo¹

2012

International Journal of Aeronautical and Space Sciences

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An advanced aeroelastic formulation for flutter analyses is presented in this paper. Refined 1D structural models were coupled with the doublet lattice method, and the g-method was used for flutter analyses. Structural models were developed in the framework of the Carrera Unified Formulation (CUF). Higher-order 1D structural models were obtained by using Taylor-like expansions of the cross-section displacement field of the structure. The order (N) of the expansion was considered as a free parameter since it can be arbitrarily chosen as an input of the analysis. Convergence studies on the order of the structural model can be straightforwardly conducted in order to establish the proper 1D structural model for a given problem. Flutter analyses were conducted on several wing configurations and the results were compared to those from literature. Results show the enhanced capabilities of CUF 1D in dealing with the flutter analysis of typical wing structures with high accuracy and low computational costs.

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Section: Aeroelastic Formulation: Doublet Lattice Methods and Mesh-to-mentioning

confidence: 99%

“…The doublet lattice method (DLM) emerged in the late 1960s [5]. More recently, an improved version of DLM has been proposed by Rodden [6], and it is this version that is utilized in this work. To date, DLM is one of the most powerful tools for linear flutter analyses in the subsonic regime.…”

Section: Introductionmentioning

confidence: 99%

Advanced 1D Structural Models for Flutter Analysis of Lifting Surfaces

Petrolo¹

2012

International Journal of Aeronautical and Space Sciences

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“…The basics of the UVLM algorithm are described by Katz and Plotkin 10 using an explicit time-stepping technique. As in other panel methods, such as the DoubletLattice, 11,12 elementary (singularity) solutions are distributed over a surface and the non-penetration boundary condition is imposed at a number of control (collocation) points, leading to a system of algebraic equations. The UVLM is based on thin-airfoil approximation, so both the elementary solutions and the collocation points are placed over the instantaneous (i.e., deformed) mean surface in lieu of the actual surface, thus effectively ignoring thickness effects.…”

Section: Aerodynamic Model: Unsteady Vortex Lattice Methodsmentioning

confidence: 99%

Stability and Open-Loop Dynamics of Very Flexible Aircraft Including Free-Wake Effects

Murua

Hesse

Palacios

et al. 2011

52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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The paper investigates the coupled aeroelasticity and flight mechanics of very flexible lightweight aircraft. A geometrically-exact composite beam formulation is used to model the non-linear flexible-body dynamics, including rigid-body motions. The aerodynamics are modeled by a general 3-D unsteady vortex-lattice method, which can capture the instantaneous shape of the lifting surfaces and the free wake, including large displacements and interference effects. The coupled governing equations are solved in a variety of ways, including linear and non-linear time-domain simulations of the full vehicle and frequencydomain linear stability analysis around trimmed configurations. The resulting framework for the Simulation of High-Aspect Ratio Planes (SHARP) provides a mid-fidelity representation of flexible aircraft dynamics, based on an intuitive and easily linearizable structural representation based on displacements and the Cartesian rotation vector, time-domain 3-D aerodynamics, and at relatively low computational costs. Previous verification studies on the structural dynamics and aerodynamics modules are complemented here with studies on the flexible-body implementation and on the integrated simulation methodology. A numerical investigation is finally presented on a representative high-altitude long-endurance model aircraft, investigating its stability properties and its open-loop dynamic response.

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“…However the growing interest in flexible-aircraft dynamics has highlighted how these models make simplifying assumptions that may not allow an accurate prediction of the air loads in these cases. Since linear unsteady aerodynamics show inaccuracies in the transonic regime, where the linear assumptions are no longer valid and the effects of viscosity and thickness are relevant, many correction techniques have been developed in the past years 3,4 to attempt to address this issue. Their aim is to introduce wind tunnel data and Computational Fluid Dynamics (CFD) results into the linear unsteady aerodynamics 5,6 to give improved predictions in this flight regime.…”

Section: Introductionmentioning

confidence: 99%

A Doublet-Lattice Method Correction Approach for High Fidelity Gust Loads Analysis

Valente¹,

Lemmens²,

Wales³

et al. 2017

58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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This paper presents a new methodology to increase the accuracy of gust loads analysis, evaluated by means of traditional potential flow models. Linearised frequency domain aerodynamic loads have been used to estimate the correction factors necessary to update the Aerodynamic Interference Coefficients matrices for gust and mode shapes deformation. The results, obtained using a corrected doublet-lattice method, are presented and compared to the fully coupled CFD/FEM results computed with a Fluid Structure Interaction interface. The application of this technique to a wing model, representative of a general single aisle civil aircraft, has shown an excellent agreement to the fully coupled results, both for rigid and flexible aerodynamic loads in the transonic regime.

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Further Refinement of the Subsonic Doublet-Lattice Method

Cited by 105 publications

References 6 publications

Advanced 1D Structural Models for Flutter Analysis of Lifting Surfaces

Advanced 1D Structural Models for Flutter Analysis of Lifting Surfaces

Stability and Open-Loop Dynamics of Very Flexible Aircraft Including Free-Wake Effects

A Doublet-Lattice Method Correction Approach for High Fidelity Gust Loads Analysis

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