scholarly journals FLOW CONTROL USING MOVING SURFACE AT THE LEADING EDGE OF AEROFOIL

2018 ◽  
Vol 47 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Kh Md Faisal ◽  
M A Salam ◽  
M A Taher Ali ◽  
Md. Samad Sarkar ◽  
Wasiul Safa ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Control Strategies ◽  
Active Flow Control ◽  
Lift Coefficient ◽  
Research Work ◽  
Leading Edge ◽  
Surface Boundary ◽  
Moving Surface ◽  
Surface Boundary Layer

Flow control is a significant topic of research in the field of aviation. Researchers in this field are continuously trying their best to find various flow control strategies in order to extract aerodynamic benefits by applying them. Applying moving surface at the leading edge of aerofoil is a type of strategy among the various types of active flow control strategies. In the present research work a rotating cylinder is added on the leading edge of the aerofoil as a moving surface in order to control the flow over its surface. The moving surface boundary layer control is applied to NACA 0018 airfoil for investigating its aerodynamic benefits and effectiveness. The moving surface is created by rotating a smooth cylinder at the leading edge of the aerofoil. The peripheral velocity of the cylinder injects momentum to the upper surface boundary layer of the aerofoil and thus delays its separation. This results in the gain in both the maximum lift coefficient and the stall angle. The work has been done at four different Reynolds Number i.e., at Re = 1.4 X 10^5, 1.85 X 10^5, 2.3 X 10^5, 2.8 X 10^5 at different angles of attack.

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 Technique For NACA 0012 Airfoil At Ultra-Low Reynolds Number

2019 ◽  
Vol 9 (2) ◽  
pp. 3788-3795
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Low Reynolds Number ◽  
Leading Edge ◽  
Control Technique ◽  
Surface Boundary ◽  
Moving Surface ◽  
Surface Boundary Layer ◽  
Number Range ◽  
Low Reynolds

Application of moving surface boundary layer control technique has been confined to relatively high Reynolds numbers. The present paper reports a numerical study of application of the above flow technique in the ultra-low Reynolds number range. A two dimensional incompressible unstructured grid based Navier Stokes solver has been used for conducting the numerical studies. Moving surface has been applied at three different portions on the airfoil surface, firstly, in the form of a rotating leading edge portion of the airfoil, secondly, a continuous moving surface from leading edge of airfoil to 57% of the chord along the leeward surface of the airfoil and thirdly a continuous moving surface from leading edge to 97% of the chord along the leeward surface of the airfoil. All the moving surface configurations show improvement of aerodynamic performance of the airfoil through enhancement of lift and decrement of drag as compared to a fixed surface one

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 Numerical study on the steady suction active flow control of hydrofoil in the profile of the blended-wing-body underwater glider

2021 ◽  
Vol 39 (4) ◽  
pp. 801-809
Author(s):  
Xiaoxu Du ◽  
Lianying Zhang
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Active Flow Control ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Flow State ◽  
Underwater Glider ◽  
Blended Wing Body ◽  
Active Flow

The hydrodynamic performance of the blended-wing-body underwater glider can be improved by opening a hole on the surface and applying the steady suction active flow control. In order to explore the influence law and mechanism of the steady suction active flow control on the lift and drag performance of the hydrofoil, which is the profile of the blended-wing-body underwater glider, based on the computational fluid dynamics (CFD) method and SST k-ω turbulence model, the steady suction active flow control of hydrofoil under different conditions is studied, which include three suction factors: suction angle, suction position and suction ratio, as well as three different flow states: no stall, critical stall and over stall. Then the influence mechanism in over stall flow state is further analyzed. The results show that the flow separation state of NACA0015 hydrofoil can be effectively restrained and the flow field distribution around it can be improved by a reasonable steady suction, so as to the lift-drag performance of NACA0015 hydrofoil is improved. The effect of increasing lift and reducing drag of steady suction is best at 90° suction angle and symmetrical about 90° suction angle, and it is better when the steady suction position is closer to the leading edge of the hydrofoil. In addition, with the increase of the suction ratio, the influence of steady suction on the lift coefficient and drag coefficient of hydrofoil is greater.

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