Wind Tunnel Wall Correction


Book Description

This report was compiled by an international team of wind tunnel wall correction experts. It presents the present state of the art in wind tunnel wall corrections with a special emphasis given to the description of modern wall correction methods based on Computational Fluid Dynamics. This AGARDograph was planned by the AGARD Fluid Dynamics Panel to be a modern sequel of the successful AGARDograph 109 "Subsonic Wind Tunnel Wall Corrections", which was published in 1966. AGARDogaph 109 is still valid and continues to be used to provide wall corrections in many wind tunnels. Nevertheless, in the thirty two years since the publication of AGARDograph 109, much work has been done on the subject, and the influence of the new tool of numerical fluid dynamics was so strong, that a sequel to AGARDograph 109 was considered to be necessary.













Wind Tunnel Wall Corrections for Arbitrary Planforms and Wind Tunnel Cross-Sections


Book Description

A computer program was developed to obtain the wind tunnel wall corrections for wing angle of attack, induced drag, and pitching moment in incompressible flow. The vortex lattice method is used for computation of these correction factors. The program can be applied to wind tunnels of arbitrary cross-sectional shape, and wings of any desired planform, subject to the constraint of straight leading and trailing edges. (Author).




On the Second-order Tunnel-wall-constriction Corrections in Two-dimensional Compressible Flow


Book Description

Solutions of the first- and second-order Prandtl-Busemann iteration equations are obtained for the flow past thin, sharp-nose, symmetric, two-dimensional bodies in closed channels. With the use of these solutions an expression is derived for the tunnel-wall interference. The tunnel-wall correction for a parabolic-arc airfoil is calculated to indicate the effects of compressibility, ratio of the tunnel height to the airfoil chord, and airfoil thickness coefficient. It appears that, for cases where the tunnel-wall corrections are significant, both the second-order effects and the variation of the correction along the chord should be considered.




Wall Interference in Wind Tunnels with Slotted and Porous Boundaries at Subsonic Speeds


Book Description

Linearized compressible-flow analysis is applied to the study of wind-tunnel-wall interference for subsonic flow in either two-dimensional or circular test sections having slotted or porous walls. Expressions are developed for evaluating blockage and lift interference.




Handbook of Wind Energy Aerodynamics


Book Description

This handbook provides both a comprehensive overview and deep insights on the state-of-the-art methods used in wind turbine aerodynamics, as well as their advantages and limits. The focus of this work is specifically on wind turbines, where the aerodynamics are different from that of other fields due to the turbulent wind fields they face and the resultant differences in structural requirements. It gives a complete picture of research in the field, taking into account the different approaches which are applied. This book would be useful to professionals, academics, researchers and students working in the field.




An Investigation of Several Slotted Wind Tunnel Wall Configurations with a High Disk Loading V/STOL Model


Book Description

The investigation reported herein is the experimental portion of a unified theoretical and experimental search for a slotted wind tunnel wall configuration with minimal interference for conventional and V/STOL models. It is shown that theory and experiment are in excellent agreement for the classical case provided an appropriate expression is used to relate the wall geometry to the boundary condition. Classical data correction equations are not appropriate for the V/STOL case, however. An additional term, not predicted by theory, is needed to account for changes in the jet wake. Geometric parameters which influence the wall interference quantities are indicated. Wall configurations are shown which will produce interference-free force data to a jet-to-free-stream velocity ratio of 4.5. (Author).




Rectangular-wind-tunnel Blocking Corrections Using the Velocity-ratio Method


Book Description

Calculations of the ratios of the velocity increments at test bodies to those at the tunnel walls caused by the solid blocking of these bodies within the walls of a closed rectangular wind tunnel are presented. The boides treated include two-dimensional airfoils; small bodies of revolution; straight, untapered, finite-span wings of varying span; and swept, untapered, finite-span wings of varying span. It is shown that, after wake blocking effects have been removed , the present method furnishes semiempirical blocking corrections for most wind-tunnel models and their components. The test section proportions of the Southern California Cooperative Wind Tunnel at CIT (ratio of height to width equal to 1/square root of 2) are used in the calculations.