Development of a Virtual Two-Dimensional Wind Tunnel Using a Vortex Element Method

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45446 ◽

2003 ◽

Author(s):

Hideaki Shono ◽

Akira Ojima ◽

Kyoji Kamemoto

Keyword(s):

Wind Tunnel ◽

Numerical Procedure ◽

Numerical Data ◽

Bluff Bodies ◽

Two Dimensional ◽

Mathematical Basis ◽

Vortex Element ◽

Unsteady Characteristics ◽

Lift And Drag ◽

Element Method

This paper describes the work of development of a virtual two-dimensional wind tunnel using a vortex element method carried by the authors group, explaining the mathematical basis of the method and structure of the virtual wind tunnel. Following the development of an advanced vortex element method, the authors proceeded to development of a virtual wind tunnel, which provides a useful tool for researchers, designers and teaching staffs in the field of fluid dynamics. As the first step of the development, construction of a two-dimensional wind tunnel has been studied. The 2-D wind tunnel works on a PC, and it has such attractive features that once a user prepares a set of numerical data of two-dimensional bodies, he or she can begin immediately unsteady calculation of a flow around either an isolated body or multiple bodies in a uniform flow without any grid-generation work. The calculation provides unsteady characteristics of lift and drag coefficients acting on each body and instantaneous flow patters visualized by distribution of vortex elements. In this paper, the numerical procedure of the vortex element method and structure of the virtual wind tunnel are briefly explained. And typical results of two-dimensional and unsteady calculation of flows around bluff bodies will be demonstrated.

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Development of Virtual Two-Dimensional wind tunnel using Vortex Element Method

The proceedings of the JSME annual meeting ◽

10.1299/jsmemecjo.2003.2.0_277 ◽

2003 ◽

Vol 2003.2 (0) ◽

pp. 277-278

Author(s):

Hideaki SHONO ◽

Akira OJIMA ◽

Kyoji KAMEMOTO

Keyword(s):

Wind Tunnel ◽

Two Dimensional ◽

Vortex Element ◽

Element Method

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Numerical and experimental analysis of two-dimensional separated flows over a flexible sail

Journal of Fluid Mechanics ◽

10.1017/s0022112002001283 ◽

2002 ◽

Vol 466 ◽

pp. 319-341 ◽

Cited By ~ 10

Author(s):

O. LORILLU ◽

R. WEBER ◽

J. HUREAU

Keyword(s):

Velocity Field ◽

Numerical Data ◽

Separated Flows ◽

Two Dimensional ◽

Dimensional Model ◽

Two Dimensional Model ◽

Wake Model ◽

Lift And Drag ◽

Particle Imaging ◽

Good Agreement

This paper is a numerical analysis of the flow over a exible sail with the usual two-dimensional model of ideal weightless incompressible fluid. The sail is assumed to be impervious, inelastic and weightless, and may or may not be mounted on a mast. Separated or attached flows are considered at any angle of attack. Our method is validated by numerical and experimental results, i.e. the sail shape and velocity field are determined by particle imaging velocimetry, and lift and drag by aerodynamic balance. Despite the simplicity of the wake model we use (the Helmholtz model), the computed free streamline geometry and especially the sail shape are in good agreement with the experimental and numerical data.

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Extensions to Maskell’s theory for blockage effects on bluff bodies in a closed wind tunnel

The Aeronautical Journal ◽

10.1017/s0001924000012380 ◽

2001 ◽

Vol 105 (1050) ◽

pp. 409-418 ◽

Cited By ~ 27

Author(s):

J. E. Hackett ◽

K. R. Cooper

Keyword(s):

Wind Tunnel ◽

Flat Plate ◽

Correction Method ◽

The Other ◽

Bluff Bodies ◽

Low Speed ◽

Test Conditions ◽

Lift And Drag ◽

Low Speed Wind Tunnel

Abstract Extensions to Maskell’s original correction method, developed over several years, are consolidated and designated ‘Maskell III’. The procedures were applied to dedicated tests on a family of flat-plate wing models in a small, low-speed wind tunnel at NRC. Test conditions included angles of attack from -10° to 110° and models of up to 16% of tunnel area. Off-centre tests were included with model-to-wall distances down to 0.72 chords. Corrected lift and drag data correlated well between models of different sizes and at different offsets from the tunnel centreline. Comparisons are made with corrections using the pressure-signature and two-variable methods, emphasising post-stall conditions. These showed that the ‘Maskell III’ procedures, which require minimal input, correlated as well as the other methods for most model sizes and positions in the tunnel.

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Analysis of Combined Conductive-Radiative Heat Transfer in a Two-Dimensional Rectangular Enclosure With a Gray Medium

Journal of Heat Transfer ◽

10.1115/1.3250509 ◽

1988 ◽

Vol 110 (2) ◽

pp. 468-474 ◽

Cited By ~ 54

Author(s):

W. W. Yuen ◽

E. E. Takara

Keyword(s):

Heat Transfer ◽

Radiative Heat Transfer ◽

Diffusion Approximation ◽

Radiative Heat ◽

Transfer Problem ◽

Numerical Procedure ◽

Numerical Data ◽

Two Dimensional ◽

One Dimensional ◽

Benchmark Solutions

Combined conductive–radiative heat transfer in a two-dimensional enclosure is considered. The numerical procedure is based on a combination of two previous techniques that have been demonstrated to be successful for a two-dimensional pure radiation problem and a one-dimensional combined conductive–radiative heat transfer problem, respectively. Both temperature profile and heat transfer distributions are generated efficiently and accurately. Numerical data are presented to serve as benchmark solutions for two-dimensional combined conductive–radiative heat transfer. The accuracy of two commonly used approximation procedures for multidimensional combined conductive–radiative heat transfer is assessed. The additive solution, which is effective in generating approximation to one-dimensional combined conductive–radiative heat transfer, appears to be an acceptable empirical approach in estimating heat transfer in the present two-dimensional problem. The diffusion approximation, on the other hand, is shown to be generally inaccurate. For all optical thicknesses and conduction-radiation parameters considered (including the optically thick limit), the diffusion approximation is shown to yield significant errors in both the temperature and heat flux predictions.

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Numerical Comparison of Dynamic Stall for Two-Dimensional Airfoils and an Airfoil Model in the DNW–TWG

Journal of the American Helicopter Society ◽

10.4050/jahs.57.042007 ◽

2012 ◽

Vol 57 (4) ◽

pp. 1-13 ◽

Cited By ~ 8

Author(s):

A. Klein ◽

Th. Lutz ◽

E. Krämer ◽

K. Richter ◽

A.D. Gardner ◽

...

Keyword(s):

Wind Tunnel ◽

Dynamic Stall ◽

Numerical Comparison ◽

Two Dimensional ◽

Tunnel Wall ◽

Unsteady Separation ◽

Wide Range ◽

Effective Angle ◽

Unsteady Characteristics ◽

Dynamics Simulations

The airfoil sections of helicopter rotors experience a wide range of flow conditions in forward flight from transonic flow on the advancing blade to subsonic flow and high angles of attack on the retreating blade. Most notably, the dynamic stall phenomenon has been a research topic for decades and various models have been introduced to predict the unsteady characteristics of the rotor blade undergoing unsteady separation. The objective of the present paper is to compare two-dimensional (2D) dynamic stall computations, suitable for airfoil design studies considering unsteady characteristics, with computational fluid dynamics simulations of the wind tunnel environment taking into account three dimensionality and wall effects. Differences between experiment and 2D computations can be partly attributed to sidewall effects, which alter the effective angle of attack at the midsection pressure measurement plane. To gain more insight into these effects, investigations are presented, which show the wind tunnel wall boundary layers and separation effects at the sidewall–airfoil junction.

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Aerodynamic Boundary Element Method for Bluff Bodies with Wind Tunnel Data Correlation

Aerotecnica Missili & Spazio ◽

10.1007/bf03404720 ◽

2016 ◽

Vol 95 (2) ◽

pp. 111-121

Author(s):

G. Bernardini ◽

G. Pierfederici ◽

J. Serafini ◽

M. Gennaretti ◽

C. Ficuciello

Keyword(s):

Boundary Element Method ◽

Wind Tunnel ◽

Boundary Element ◽

Bluff Bodies ◽

Data Correlation ◽

Wind Tunnel Data ◽

Element Method

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Cavities at atmospheric pressure behind two-dimensional bodies at an angle of attack

The ANZIAM Journal ◽

10.1017/s1446181100009809 ◽

2005 ◽

Vol 47 (1) ◽

pp. 103-119

Author(s):

P. M. Haese

Keyword(s):

Atmospheric Pressure ◽

Angle Of Attack ◽

The Body ◽

Bluff Bodies ◽

Two Dimensional ◽

Physical Conditions ◽

Drag Forces ◽

Lift And Drag ◽

Drag Ratio ◽

Lift To Drag Ratio

AbstractThis paper presents an interior source method for the calculation of semi-infinite cavities behind two-dimensional bluff bodies placed at an angle of attack in a uniform stream. Aspects under consideration include the pressure distribution along the body, especially just ahead of the separation point, lift and drag forces, and how these quantities vary with the angle of attack. We include discussion of the physical conditions of separation, and identify critical angles of attack for which the cavitating flow past an airfoil may (a) become unstable, or (b) yield the greatest lift to drag ratio.

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