An inverse boundary element method for single component airfoil design

Soinne, Erkki; Laine, Seppo

doi:10.2514/3.45162

Cited by 10 publications

(5 citation statements)

References 2 publications

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“…At each station the shape factor was defined from a combination of measurement and prediction, and the flow at the station was modelled by an F-S boundary layer with the same shape factor. Also, the pressure gradients around the aerofoil were predicted theoretically using the method of Soinne & Laine (1988). It was found that by matching the shape factors at each chordwise station, the pressure gradient calculated from the selected F-S profile matched that calculated for the aerofoil typically to within 20 %.…”

Section: Theoretical Modelling Of Instability Characteristicsmentioning

confidence: 97%

Boundary-layer instability noise on aerofoils

1999

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An experimental and theoretical investigation has been carried out to understand the tonal noise generation mechanism on aerofoils at moderate Reynolds number. Experiments were conducted on a NACA0012 aerofoil section in a low-turbulence closed working section wind tunnel. Narrow band acoustic tones were observed up to 40 dB above background noise. The ladder structure of these tones was eliminated by modifying the tunnel to approximate to anechoic conditions. High-resolution flow velocity measurements have been made with a three-component laser-Doppler anemometer (LDA) which have revealed the presence of strongly amplified boundary-layer instabilities in a region of separated shear flow just upstream of the pressure surface trailing edge, which match the frequency of the acoustic tones. Flow visualization experiments have shown these instabilities to roll up to form a regular Kármán-type vortex street.A new mechanism for tonal noise generation has been proposed, based on the growth of Tollmien-Schlichting (T-S) instability waves strongly amplified by inflectional profiles in the separating laminar shear layer on the pressure surface of the aerofoil. The growth of fixed frequency, spatially growing boundary-layer instability waves propagating over the aerofoil pressure surface has been calculated using experimentally obtained boundary-layer characteristics. The effect of boundary-layer separation has been incorporated into the model. Frequency selection and prediction of T-S waves are in remarkably good agreement with experimental data.

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Section: Theoretical Modelling Of Instability Characteristicsmentioning

confidence: 97%

Boundary-layer instability noise on aerofoils

1999

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“…(6) and (10). Avoiding subsequent matrix operations is a significant point in favor of iterative-calculation economy, because the matrix setup and inversion of influence coefficients are the most time-consuming procedures in the panel methods.…”

Section: Panel Methodsmentioning

confidence: 96%

“…For evaluation of the overall transition modeling, two different angles of attack with different transition models have been used at Re = 3 × 10 6 . The results are shown in Tables 2 and 3.…”

Section: Evaluating the Analysis Methods Evaluation Of The Transition mentioning

confidence: 99%

See 1 more Smart Citation

Viscous-Inviscid Method for Airfoil Analysis and Design for Aviation and Windmills

Peltonen

2006

Journal of Aircraft

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This study examines an advanced viscous-inviscid interactive method developed for the analysis and design of airfoils in two-dimensional subsonic compressible flow (Ma ∞ < 0.4). Inviscid flow is solved with a panel method. The laminar boundary layer is calculated by Thwaites' method. Transition is determined by Michel's relation or the e n method. An integral solution for a turbulent boundary layer is derived from an entrainment equation. Closure conditions are obtained with empirical relations. Singularities near the separation are avoided by inverting the boundary-layer method. Inviscid and viscous flows are coupled with transpiration. The analysis method is used as a "black box" in the design tasks. The geometry of the starting airfoil is perturbed iteratively by transpiration until the pressure distribution converges to a predefined target. This study proposes the necessary degrees of freedom in the target velocity distribution to obtain a closed airfoil. Design cases are included, which support the general applicability and accuracy of the numerical design method.

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“…A three dimensional version of the SFC formulation remains to be developed. A similar concept derived from the boundary element integral method" gives a fully converged solution for an airfoil design on a -personal computer in[10][11][12][13][14][15][16][17][18][19][20] iterations.…”

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confidence: 99%

Aerodynamic shape design and optimization

Dulikravich

1991

29th Aerospace Sciences Meeting

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An inverse boundary element method for single component airfoil design

Cited by 10 publications

References 2 publications

Boundary-layer instability noise on aerofoils

Boundary-layer instability noise on aerofoils

Viscous-Inviscid Method for Airfoil Analysis and Design for Aviation and Windmills

Aerodynamic shape design and optimization

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