Surface suction on aerofoil aerodynamic characteristics at transonic speeds

1998 ◽  
Vol 212 (5) ◽  
pp. 339-351 ◽  
Author(s):  
N Qin ◽  
Y Zhu ◽  
D I A Poll
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Active Flow Control ◽  
Effective Means ◽  
Active Surface ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Surface Suction ◽  
Lift And Drag ◽  
Active Flow

This paper presents a numerical study of the effects of an active flow control through surface suction on shock boundary layer interactions over transonic aerofoils. Two different aerofoils were studied. Firstly, for the purpose of validation, an NACA64A010 aerofoil with a trailing edge flap was investigated and the numerical results were compared with experimental data with and without suction for surface pressure distributions and lift and drag coefficients. Grid sensitivity has also been studied regarding the numerical accuracy. The second geometry was an RAE9647 aerofoil, which was designed for superior aerodynamic performance when applied to a helicopter rotor blade. An active surface was used to prevent or alleviate shock-induced separation. The suction strength and location were varied to determine the effect on aerodynamic performance and to provide an effective means of suppressing undesirable flow features. In both cases, increases in both lift and drag were observed when surface suction was applied. However, the benefit of suction appeared in the form of a substantial increase in the lift-drag ratio. It was also found that the shock location and strength are very sensitive to the suction location and strength. Two different mechanisms for active flow control over transonic aerofoils are discussed.

Study on the Effects of Active Flow Control on Aerodynamic Performance of Two Airfoils in Tandem Configuration

2017 ◽  
Author(s):  
Ehsan Asgari ◽  
Armin Sheidani ◽  
Mehran Tadjfar
Keyword(s):  
Flow Control ◽  
Drag Coefficient ◽  
Active Flow Control ◽  
Aerodynamic Characteristics ◽  
Primary Objective ◽  
Tandem Configuration ◽  
Drag Forces ◽  
Lift And Drag ◽  
Lift And Drag Coefficient ◽  
Active Flow

Aerodynamic investigation of tandem airfoil configuration has so many applications in different industries that has become a topic of scientific interest since many years ago. One can name a lot of applications in this field such as the aerodynamic interaction between a wing and a tail or a wing and a flap of an aircraft, blades of a rotor and a stator in a compressor or turbine, the tandem blades in the rotor of a compressor, wings of an MAV, to name but a few. The primary objective of this research is to investigate the effect of active flow control (AFC) on two airfoils in tandem configuration, in which the upstream airfoil undergo pitching motion and the downstream airfoil is stationary. In the first place, the aerodynamic characteristics of airfoils in tandem configuration such as lift and drag coefficient is obtained when there is no flow control on the airfoils (clean case). Following this, the mentioned quantities are calculated for the airfoils when AFC has been applied on the forefoil. In order to analyze the effect of AFC and tandem configuration aerodynamic characteristics, the lift and drag coefficient of clean case is compared to those of the controlled case. The result suggests that AFC has caused the amount of CL to grow significantly. It was also observed that the tandem configuration had little influence on the forefoil. On the other hand, the vortices coming from the upstream airfoil generated thrust on the hindfoil. In case of AFC, our results suggest that fluctuations of both lift and drag forces decrease in the hindfoil. It is worth mentioning that this research is among the firsts studying the effect of AFC on tandem airfoils and will pave the way for those who are interested in this field.

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.

Increasing the Aerodynamic Performance of a Formula Student Race Car by Means of Active Flow Control

2019 ◽  
Author(s):  
Ben Steinfurth ◽  
Arne Berthold ◽  
Steffen Feldhus ◽  
Frank Haucke ◽  
Julien Weiss
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Aerodynamic Performance ◽  
Race Car ◽  
Active Flow

Aerodynamic Characteristics of a Blended-Wing-Body Aircraft With A Serpentine Inlet Using Flow Control Techniques

2021 ◽  
Author(s):  
Min-Sik Youn ◽  
Youn-Jea Kim
Keyword(s):  
Flow Control ◽  
Flow Separation ◽  
High Efficiency ◽  
Active Flow Control ◽  
Quantitative Measure ◽  
Aerodynamic Characteristics ◽  
Interface Plane ◽  
Flow Distortion ◽  
Blended Wing Body ◽  
Active Flow

Abstract Demands of a modern aircraft regarding its aerodynamic performance and high efficiency are ever-growing. An S-shaped inlet, as known as a serpentine duct, plays a significant role in increasing fuel efficiency. Recently, the serpentine duct is commonly employed for military aircraft to block the front of the jet engine from radar. However, delivering a non-uniformly distorted flow to the engine face (aerodynamic interface plane, AIP) though a serpentine duct is inevitable due to the existence of flow separation and swirl flow in the duct. The effect of distortion is to cause the engine compressor to surge; thus, it may impact on the life-cycle of aircraft engine. In this study, aerodynamic characteristics of a serpentine duct mounted on a blended-wing-body (BWB) aircraft was thoroughly investigated to determine where and how the vortex flow was generated. In particular, both passive and active flow control were implemented at a place where the flow separation was occurred to minimize the flow distortion rate in the duct. The passive and active flow control systems were used with vortex generator (VG) vanes and air suctions, respectively. A pair of VG s have been made as a set, and 6 sets of VG in the serpentine duct. For the active flow control, 19 air suctions have been implemented. Both flow control devices have been placed in three different locations. To evaluate the performance of flow control system, it is necessary to quantify the flow uniformity at the AIP. Therefore, coefficient of distortion, DC(60) was used as the quantitative measure of distortion. Also, change in DC(60) value while the BWB aircraft is maneuvering phase was analyzed.

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