Obtaining Extremely High Lift to Drag Ratios with Flexible-Wall Turbulence Control

Hendrix, Jim

doi:10.2514/6.2009-896

Cited by 4 publications

(2 citation statements)

References 11 publications

(22 reference statements)

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“…For example, using a Deturbulator tape on the top surface of a sailplane wing has been found to enhance the best lift-drag ratio (L/D) by 18% in independently validated flight tests 9 . Oil flow visualization has shown evidence of stagnated separated flow on the wing 10 . Deturbulators have also been found to improve fuel economy of tractor trailer trucks by more effectively hiding the load on an open trailer in more stagnant air, or by more effectively shielding the front face of a van-trailer within a stagnated separated zone 3,11 .…”

Section: Large-eddy Break-up With Flexible Surface Deturbulatorsmentioning

confidence: 99%

Modeling Turbulence Control Effect of the SINHA Flexible Composite Surface Deturbulator

Wang

Walters

Coley

et al. 2012

30th AIAA Applied Aerodynamics Conference

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The effect of treating an aerodynamic surface with a Flexible Composite Surface Deturbulator (FCSD) has been modeled using Loci/CHEM, a RANS CFD code. The FCSD is postulated to control turbulent mixing by utilizing its ridged substrate to break up long wavelength flow instabilities imposed on its flexible surface. To mimic this cost-effectively, a turbulence length scale limiter has been selectively applied to the k-ω turbulence model, thereby constraining the length scale of turbulence production. CFD predictions of a Deturbulator treated deflector oriented 30 degrees with respect to the freestream validate the wave breakdown effect when compared to wind tunnel measurements. Simulations of a S809 wind turbine airfoil have yielded modified 20% lower low-skin friction marginally separated boundary layers over 95% of the chord on the upper surface, and a 2% increase in L/D.

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Section: Large-eddy Break-up With Flexible Surface Deturbulatorsmentioning

confidence: 99%

Modeling Turbulence Control Effect of the SINHA Flexible Composite Surface Deturbulator

Wang

Walters

Coley

et al. 2012

30th AIAA Applied Aerodynamics Conference

Self Cite

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“…Hubner [47][48], who focused on the trailing edge scalloping effect ( Figure 2), has obtained results in line with Lee & Lee. Sinha [49][50][51] has studied a variable shape deturbulator taken from a composite deformable surface, made of a flexible membrane mounted on support ridges (Figure 3).…”

Section: Introductionmentioning

confidence: 99%

Analysis of triangular sharkskin profiles according to second law

Liversage¹,

Trancossi²

2018

MMC_B

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This paper presents the analysis of a case of sharkskin effect, caused by a turbulent flow over rough engineered surfaces. From a large bibliographic analysis, the paper describes the preliminary CFD simulations of a series of profiles such as sawtooth profile (12x6 mm), scalloped (R=6mm) and triangular (6x2 mm). Although a best solution has not been identified, different geometries and dimensions have been analysed and the initial results have shown the potential of a triangular profile with a 90° angle on top implemented on Coanda affected surfaces. The reference test profile adopted is an elevated surface with an inclined step placed upwind. The corrugated surface has been applied to analyse the coupled effect of sharkskin on both the viscous and pressure terms of drag. The results allow the assessment of a mathematical model of the sharkskin behaviour, assuming a continuous profile of the riblets. Results have also been assessed against a flat planar surface with the same measurements. The outcome has demonstrated a potential reduction up to 30% in the wall shear stress. The analysis has led to the formulation of a new equation to calculate the drag and lift force as a function of Bejan number. This model opens the possibility of applying a second law of analysis method to aerodynamic and fluid dynamic effects. Although this model has not been sufficiently demonstrated, it can allow a theoretical calculation of entropy generation in the case of the specific fluid dynamic phenomenon.

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Bionic gradient flexible fish skin acts as a passive dynamic micro-roughness to drag reduction

Chen

Cui

Liu

et al. 2023

Surface and Coatings Technology

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Obtaining Extremely High Lift to Drag Ratios with Flexible-Wall Turbulence Control

Cited by 4 publications

References 11 publications

Modeling Turbulence Control Effect of the SINHA Flexible Composite Surface Deturbulator

Modeling Turbulence Control Effect of the SINHA Flexible Composite Surface Deturbulator

Analysis of triangular sharkskin profiles according to second law

Bionic gradient flexible fish skin acts as a passive dynamic micro-roughness to drag reduction

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