Leading-edge rotating cylinder for boundary-layer control on lifting surfaces

1975 ◽  
Vol 9 (2) ◽  
pp. 76-78 ◽  
Author(s):  
W.S. Johnson ◽  
J.S. Tennant ◽  
R.E. Stamps
Keyword(s):  
Boundary Layer ◽  
Leading Edge ◽  
Rotating Cylinder ◽  
Boundary Layer Control ◽  
Lifting Surfaces ◽  
Layer Control

scholarly journals Moving Surface Boundary Layer Control Analysis and the Influence of the Magnus Effect on an Aerofoil with a Leading-Edge Rotating Cylinder

2019 ◽  
Author(s):  
Md. Abdus Salam ◽  
Bhuiyan Shameem Mahmood Ebna Hai ◽  
M. A. Taher Ali ◽  
Debanan Bhadra ◽  
Nafiz Ahmed Khan
Keyword(s):  
Boundary Layer ◽  
Free Stream ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Rotating Cylinder ◽  
Boundary Layer Control ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Lower Velocity ◽  
Layer Control

A number of experimental and numerical studies point out that incorporating a rotating cylinder can superiorly enhance the aerofoil performance, especially for higher velocity ratios. Yet, there have been less or no studies exploring the effects of lower velocity ratio at a higher Reynolds number. In the present study, we investigated the effects of Moving Surface Boundary-layer Control (MSBC) at lower velocity ratios (i.e. cylinder tangential velocity to free stream velocity) and higher Reynolds number on a symmetric aerofoil (e.g. NACA 0021) and an asymmetric aerofoil (e.g. NACA 23018). In particular, the aerodynamic performance with and without rotating cylinder at the leading edge of the NACA 0021 and NACA 23018 aerofoil was studied on the wind tunnel installed at Aerodynamics Laboratory. The aerofoil section was tested in the low subsonic wind tunnel, and the lift coefficient and the drag coefficient were studied for different angles of attack. The experiments were conducted for two Reynolds numbers: 200000 and 250000 corresponding to two free stream velocities: 20 m/s and 25 m/s, respectively, for six different angle of attacks (-5°, 0°, 5°, 10°, 15° and 20°). This study demonstrates that the incorporation of a leading edge rotating cylinder results in an increase of lift coefficient at lower angle of attacks (maximum around 33%) and delay in stall angle (from 10° to 15°) relative to the aerofoil without rotating cylinder.

scholarly journals Moving Surface Boundary Layer Control Analysis and the Influence of the Magnus Effect on an Aerofoil with a Leading-Edge Rotating Cylinder

2019 ◽  
Author(s):  
Md. Abdus Salam ◽  
Bhuiyan Shameem Mahmood Ebna Hai ◽  
M. A. Taher Ali ◽  
Debanan Bhadra ◽  
Nafiz Ahmed Khan
Keyword(s):  
Boundary Layer ◽  
Free Stream ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Rotating Cylinder ◽  
Boundary Layer Control ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Lower Velocity ◽  
Layer Control

A number of experimental and numerical studies point out that incorporating a rotating cylinder can superiorly enhance the aerofoil performance, especially for higher velocity ratios. Yet, there have been less or no studies exploring the effects of lower velocity ratio at a higher Reynolds number. In the present study, we investigated the effects of Moving Surface Boundary-layer Control (MSBC) at lower velocity ratios (i.e. cylinder tangential velocity to free stream velocity) and higher Reynolds number on a symmetric aerofoil (e.g. NACA 0021) and an asymmetric aerofoil (e.g. NACA 23018). In particular, the aerodynamic performance with and without rotating cylinder at the leading edge of the NACA 0021 and NACA 23018 aerofoil was studied on the wind tunnel installed at Aerodynamics Laboratory. The aerofoil section was tested in the low subsonic wind tunnel, and the lift coefficient and the drag coefficient were studied for different angles of attack. The experiments were conducted for two Reynolds numbers: 200000 and 250000 corresponding to two free stream velocities: 20 m/s and 25 m/s, respectively, for six different angle of attacks (-5°, 0°, 5°, 10°, 15° and 20°). This study demonstrates that the incorporation of a leading edge rotating cylinder results in an increase of lift coefficient at lower angle of attacks (maximum around 33%) and delay in stall angle (from 10° to 15°) relative to the aerofoil without rotating cylinder.

Endwall Boundary Layer Control in Compressor Cascades

2004 ◽  
Author(s):  
Ralf Mu¨ller ◽  
Konrad Vogeler ◽  
Helmut Sauer ◽  
Martin Hoeger
Keyword(s):  
Boundary Layer ◽  
Leading Edge ◽  
Suction Side ◽  
Boundary Layer Control ◽  
Compressor Cascade ◽  
Low Speed ◽  
Passage Vortex ◽  
Additional Losses ◽  
Layer Control ◽  
Horse Shoe Vortex

Recent investigations have shown a reduction of secondary losses in compressor cascades using a bulb like modification of the profile at the endwall. This paper is focussed on experimental work in comparison of 5 different endwall modifications at a compressor cascade. The cascade is modified near the endwall with a bulb, a medium and a large fillet. The fillet configurations are modified by an axial blunt cut-off at the leading edge. The investigations have been carried out at a profile developed from a hub section of the Dresden Low Speed Research Compressor (LSRC) blade, a compressor profile with a nominal turning of 18 deg. A datum configuration and the 5 other configurations were tested at the Low Speed Cascade Windtunnel (LSCW). For the bulb configuration, an intensified horse shoe vortex was suspected and observed counterrotating to the passage vortex with an influence on its propagation. The interaction of the passage vortex and the suction side profile boundary layer is influenced. The superposition of both is minimized and the losses developing from this effect are significant lower. For the fillet and blunt-fillet configurations, a fillet vortex develops and was observed co-rotating to the passage vortex with an influence on the mentioned interaction as well. Blunt leading edges produce additional losses but the superposition of the growing vortices may reduce the overall losses. The cases show a reduction in losses of 1.9% for 3 deg incidence and a range of 1.2% rise to 1.9% reduction in dependence of the incidence. This equals a reduction of the isolated secondary losses up to 28% with respect to the reference profile. Detailed results of the experiments are presented for the reference and all modified cascades.

YC-14 System for Leading-Edge Boundary-Layer Control

1976 ◽  
Vol 13 (2) ◽  
pp. 149-152
Author(s):  
Hubert L. Ernst ◽  
Alankar Gupta
Keyword(s):  
Boundary Layer ◽  
Leading Edge ◽  
Boundary Layer Control ◽  
Layer Control

Aerodynamic Aspects of Boundary Layer Control for High Lift at Low Speeds

1963 ◽  
Vol 67 (628) ◽  
pp. 201-223 ◽  
Author(s):  
John Williams ◽  
Sidney F. J. Butler
Keyword(s):  
Boundary Layer ◽  
Leading Edge ◽  
Boundary Layer Control ◽  
Trailing Edge ◽  
High Lift ◽  
Air Jets ◽  
Slot Suction ◽  
Trailing Edge Flaps ◽  
Trailing Edge Flap ◽  
Layer Control

Summary:The usefulness of boundary-layer control (B.L.C.) at the knee of a trailing-edge flap, over the wing nose close to the leading-edge or at the knee of a leading-edge flap is first noted. Various methods of providing B.L.C. are outlined, comprising slot blowing, slot suction, area suction, inclined air-jets, and specially-designed aerofoil shapes. The aerodynamic aspects of slot blowing over trailing-edge flaps and the wing nose are then examined in detail and both slot suction and area suction are also considered. The associated practical design features required for good performance are discussed and some flight-handling implications are mentioned.

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