Drag-Breakdown Methods from Wake Measurements

Méheut, Michaël; Bailly, Didier

doi:10.2514/1.29051

Cited by 62 publications

(31 citation statements)

References 3 publications

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“…Nonetheless, this method based on the vorticity can only be applied to threedimensional (3-D) flows. Meanwhile, ONERA has developed its own theoretical formulations [19], in particular, an original method of wave drag extraction that can be applied both to 2-and 3-D flows.…”

Section: Drag Extraction From Wake Surveymentioning

confidence: 99%

Experimental and Numerical Methods for Transition and Drag Predictions of Laminar Airfoils

et al. 2015

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The friction component is responsible for more than 40% of typical civil aircraft drag. As a consequence, the issue of laminar flow has been of prime importance in aeronautics for many years now. This article is focused on TollmienSchlichting-induced transition and drag predictions of two-dimensional laminar airfoils obtained with experimental and numerical methods. In 2012, a test campaign in the ONERA-S2MA wind tunnel, including infrared acquisitions, pressure sensors, and wake analyses, allowed substantial data to be obtained on such airfoils in transonic conditions. To complete this study, two-dimensional fluid dynamics computations have been performed, either with a Reynoldsaveraged Navier-Stokes solver using transition criteria or with a boundary-layer code combined with direct stability analysis. Furthermore, experimental (wake survey) and numerical (far-field theory) techniques allowing airfoil drag breakdown have been employed. Wind-tunnel and computational fluid dynamics transition predictions have been compared. Good agreement has been observed but the transition criteria may show some limitations in particular situations, such as long separation bubble development. The gains in lift and drag due to laminar flow have been quantified (natural vs triggered transition). Concerning drag reduction, the importance of the viscous pressure component has been highlighted. Finally, the effects of parameters such as angle of attack, Mach number, and Reynolds number on transition location and drag have been investigated.subscript for local state value f = frequency of boundary-layer instability M = freestream Mach number N T = value of factor N at transition onset P i = stagnation pressure Re = freestream Reynolds number based on the airfoil chord T i = stagnation temperature Tu = turbulence level U, V, W = x, y, z velocity components x, y, z = x, y, z coordinates Y = normalized first cell height Λ 2 = mean Pohlhausen parameter ρ = density Subscript 0 = freestream state value

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Section: Drag Extraction From Wake Surveymentioning

confidence: 99%

Experimental and Numerical Methods for Transition and Drag Predictions of Laminar Airfoils

et al. 2015

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“…The recent efforts of VanDam [6], Giles and Cummings [7], and Kusunose [8] have treated the general compressible case, also with enthalpy addition from engines. More recently, Méheut and Bailly [9] have done an overview and comparison of most of the previous analyses and approaches for the drag component, and introduce their own refinement. Spalart [10] performs an even more detailed analysis for the incompressible case using inner and outer expansions of the far wake, and identifies a higher-order farfield term in the overall axial force which has been previously neglected.…”

Section: Introductionmentioning

confidence: 99%

Power Balance in Aerodynamic Flows

Drela

2009

27th AIAA Applied Aerodynamics Conference

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A control volume analysis of the compressible viscous flow about an aircraft is performed, including integrated propulsors and flow control systems. In contrast to most past analyses which have focused on forces and momentum flow, in particular thrust and drag, the present analysis focuses on mechanical power and kinetic energy flow. The result is a clear identification and quantification of all the power sources, power sinks, and their interactions which are present in any aerodynamic flow. The formulation does not require any separate definitions of thrust and drag, and hence it is especially useful for analysis and optimization of aerodynamic configurations which have tightly integrated propulsion and boundary layer control systems. x, y, z cartesian axes

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“…In Q3D analysis, this method of computing the wing drag is not possible as the induced drag is not computed in strip theory. For this reason, the induced drag is determined through Trefftz Plane analysis using the VLM, which is a form of far-field analysis [32,33].…”

Section: Q3d Aerodynamic Analysismentioning

confidence: 99%