Computational design of a test article to investigate 2-D surface excrescences on a swept laminar-flow wing

Tufts, Matthew W.; Duncan, Glen T.; Crawford, Brian K.; Reed, Helen L.; Saric, William S.

doi:10.1504/ijesms.2014.063123

Cited by 7 publications

(2 citation statements)

References 14 publications

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“…It is therefore not computationally feasible to simply model all of these effects directly, meaning using a single grid with sufficient points to properly capture all the relevant phenomena. The first step was to calculate the flowfield surrounding the entire aircraft in a manner similar to that described in past FRL experiments by Rhodes et al 114 and Tufts et al 118 for a clean (no excrescences) model. These flight conditions were then used to inform the boundary conditions for smaller (in spatial dimensions) grids surrounding the immediate area of the step excrescence (Tufts et al 121 ).…”

Section: Swifter/swiftest Computationsmentioning

confidence: 99%

Receptivity: The Inspiration of Mark Morkovin (Invited)

Reed

Saric

2015

45th AIAA Fluid Dynamics Conference

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This paper provides a review of the current findings in receptivity for subsonic/transonic flows, including a discussion of the origin of the concept via Mark Morkovin, a remarkable aeronautical engineer, educator, and colleague. Disturbances external to the boundary layer -whether freestream sound or vorticity -can interact with surface roughness, the leading edge, or other inhomogeneities and enter the boundary layer as steady and/or unsteady fluctuations of the basic state. This process establishes the initial conditions of disturbance amplitude, frequency, phase, and scales for the breakdown of laminar flow. The past decades have seen considerable progress in the understanding of receptivity mechanisms guided by the roadmap (Morkovin et al. 1 ).

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Section: Swifter/swiftest Computationsmentioning

confidence: 99%

Receptivity: The Inspiration of Mark Morkovin (Invited)

Reed

Saric

2015

45th AIAA Fluid Dynamics Conference

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“…10. In 2005-13 Texas A&M Flight Research Laboratory investigated laminar flow control including plasma actuators, discrete roughness elements, and excrescence studies [11,[26][27][28][29][30][31][32][33][34]. The Swept-Wing Inflight Testbed (SWIFT) was mounted on the left outboard wing pylon of a Cessna O-2A (Fig.…”

Section: B Previous Flight Research Programsmentioning

confidence: 99%

A Flight Test Technique for Precise Angle-of-Attack Measurements with Application to Laminar Flow Control Flight Research

Tucker

Saric

Reed

2014

52nd Aerospace Sciences Meeting

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Flight data collected on a wing glove testbed are very sensitive to flight conditions (e.g., Mach number, Reynolds number, aircraft weight). Previous laminar flow control flight research has typically been narrowly focused on single point designs such as the cruise condition. The objectives for the present experiment are to collect these data across a range of flight conditions and provide stabilized flow data suitable for computational validation. To accomplish this, a flight test technique was developed to set and hold the angle of attack of a wing glove. This is accomplished via lateral-directional flight control inputs which are not susceptible to pilot-induced oscillations like pitch inputs. When applied to laminar flow control, this flight test technique is shown to be able to reasonably hold angle of attack to ±0.1°. Further, a combination of flight control inputs can compensate for asymmetric wing glove installation and position flight control surfaces for optimal data collection and comparison to computational models. Finally, a research pilot display was developed to display flow conditions at the wing glove and enable efficient flight data collection. Nomenclature α = aircraft angle of attack α test = aircraft angle of attack specified for flight data collection α tol = aircraft angle of attack tolerance β = aircraft angle of sideslip AIAA SciTech 2 = isentropic expansion factor Γ = wing geometric dihedral δ a = aileron displacement δ a, left = left aileron displacement, positive trailing edge down δ a, right = right aileron displacement, positive trailing edge up δ a, trim = aileron displacement required to null the lateral rates of the aircraft δ r = rudder displacement, positive trailing edge right δ r, trim = rudder displacement required to null the directional rates of the aircraft ΔΦ = change in bank angle ΔL = change in aircraft lift  = aircraft glide angle Θ = aircraft pitch angle Λ = wing leading edge sweep referenced to aircraft longitudinal axis Λ eff = wing effective leading edge sweep referenced to freestream velocity μ = viscosity of air = density of air  = aircraft bank angle  limit = aircraft bank angle limit  test = aircraft test bank angle a = speed of sound b = aircraft wingspan B = 10 9 c = chord length C L = wing lift coefficient C l β = rolling moment coefficient with respect to angle of sideslip C L α = wing lift coefficient with respect to angle of attack C L 0 = wing lift coefficient at zero angle of attack ft MSL = feet above mean sea level Downloaded by UNIVERSITY OF NEW SOUTH WALES on July 30, 2015 | http://arc.aiaa.org | 3 h = aircraft altitude KIAS = knots indicated airspeed L = aircraft lift M = Mach number p = atmospheric pressure R = specific gas constant for air Re c = Reynolds number, chord reference length S = aircraft wing area T = temperature U ∞ = freestream velocity U n = component of X-direction freestream velocity normal to the wing leading edge U p = component of X-direction freestream velocity parallel to the wing leading edge V = component of free stream...

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