ISSN:
1573-1987
Keywords:
aerofoil manipulators
;
LEBUs
;
CFD
;
drag prediction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A computational study has been conducted to determine the variation of device drag with profile shape and angle of attack for aerofoil boundary-layer manipulators (LEBUs) operating at high subsonic Mach numbers. Calculations have been made at a free-stream Mach number of 0.80 for both symmetrical and asymmetrical NACA-00xx and 44xx series devices including an inverted cambered NACA-4409 profile. The LEBUs considered were located in a turbulent boundary-layer at a mid-chord heighth equivalent to 0.67δ from the wall. The present investigations sought to confirm suggestions based upon experimental observations that there may be some advantage in replacing a symmetrical device by an inverted asymmetrical profile form. The computations were performed using an unstructured adaptive-mesh 3D Navier-Stokes code incorporating a Lam and Bremhorst low-Reynolds number two-equationk — ε turbulence model. The calculated flow field around a NACA-0009 aerofoil at zero angle of attack was initially verified against experimental interferometric data. The calculated device drag coefficient at zero incidence was 0.026 for the NACA-0009, similar to that measured in experiments. However predicted drag for an inverted NACA-4409 was 0.085, this being considerably higher than anticipated. The results suggested that a slightly positive angle of attack may help minimise device drag but neither profile is appropriate for use in transonic conditions. Improved results may be obtained from inverted flat-topped profiles designed to minimise losses associated with localised shocks.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00863513
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