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.

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.

scholarly journals Numerical Analysis of the Aerodynamic Characteristics of NACA-4312 Airfoil

2020 ◽  
Vol 01 (02) ◽  
pp. 29-36
Author(s):  
Md Rhyhanul Islam Pranto ◽  
Mohammad Ilias Inam
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Numerical Results ◽  
Ansys Fluent ◽  
Coefficient Increase ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

The aim of the work is to investigate the aerodynamic characteristics such as lift coefficient, drag coefficient, pressure distribution over a surface of an airfoil of NACA-4312. A commercial software ANSYS Fluent was used for these numerical simulations to calculate the aerodynamic characteristics of 2-D NACA-4312 airfoil at different angles of attack (α) at fixed Reynolds number (Re), equal to 5×10^5 . These simulations were solved using two different turbulence models, one was the Standard k-ε model with enhanced wall treatment and other was the SST k-ω model. Numerical results demonstrate that both models can produce similar results with little deviations. It was observed that both lift and drag coefficient increase at higher angles of attack, however lift coefficient starts to reduce at α =13° which is known as stalling condition. Numerical results also show that flow separations start at rare edge when the angle of attack is higher than 13° due to the reduction of lift coefficient.

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.

scholarly journals The Effect of Spoiler Shape and Setting Angle on Racing Cars Aerodynamic Performance

2020 ◽  
Vol 5 (1) ◽  
pp. 11-20
Author(s):  
Hesam Eftekhari ◽  
Abdulkareem Sh. Mahdi Al-Obaidi ◽  
Shahrooz Eftekhari
Keyword(s):  
Drag Coefficient ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Ansys Fluent ◽  
Aerodynamic Efficiency ◽  
Race Car ◽  
Setting Angle ◽  
Being There ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

Automotive racing is one of the favorite sports of human being. There have been many developments in past decades by car engineers to improve the performance of the engine and increase the aerodynamic efficiency of the race cars to achieve a better lap time and get a better placement safely. One of the ways to improve the aerodynamic performance of a race car is to use rear spoilers. This study by using ANSYS FLUENT numerically investigated the effect of the spoiler shape and setting angle on the aerodynamic characteristics of a race car and then it was validated by conducting wind tunnel experiment. Lift and drag coefficient of NACA0012, NACA4412, and S1223 are determined in Reynold’s number of 2×105 as an airfoil and as spoiler on ERC model which is a conceptual car model inspired by Porsche 911. It was found that ERC model with spoiler would have better aerodynamic efficiency compared to ERC model without spoiler. Also, S1223 at -6 degrees was identified as the optimized configuration as it generates the highest downforce. Even though the drag coefficient at this setting angle is slightly higher, but in terms of stability and handling IT is at its best. Overall, this study would help car manufacturers, for racing and commercial purposes, to have a better insight into the effect of spoiler configuration on the aerodynamic performance of cars. Hence, the stability, handling, and efficiency of the cars can be further improved by selecting the suitable spoiler configuration.

Helicopter Fuselage Model Drag Reduction by Active Flow Control Systems

2019 ◽  
Vol 64 (2) ◽  
pp. 1-15 ◽  
Author(s):  
Fabrizio De Gregorio
Keyword(s):  
Experimental Investigation ◽  
Flow Control ◽  
Control Systems ◽  
Flow Separation ◽  
Laboratory Tests ◽  
Active Flow Control ◽  
Aerodynamic Characteristics ◽  
Pulsed Jets ◽  
Wide Range ◽  
Active Flow

A comprehensive experimental investigation of a helicopter blunt fuselage model was carried out to evaluate the effectiveness of active flow control (AFC) systems in reducing parasite fuselage drag. The main objective was to demonstrate the capability of different active technologies to decrease fuselage drag by alleviating the flow separation in the loading ramp region of large transport helicopters. The work was performed on a simplified blunt fuselage at model scale. Two different flow control actuators were considered for evaluation: steady blowing and unsteady blowing (i. e., pulsed jets). Laboratory tests of each individual actuator were performed to assess their performance and properties. The fuselage model was investigated with and without the AFC systems located along the loading ramp edges. Significant drag reductions were achieved for a wide range of fuselage angles of attack and sideslip angles without negatively affecting other aerodynamic characteristics.

Numerical Simulation of Flow Control on Marine Riser With Attached Splitter Plate

2010 ◽  
Author(s):  
Jiasong Wang ◽  
Hua Liu ◽  
Fei Gu ◽  
Pengliang Zhao
Keyword(s):  
Numerical Simulation ◽  
Flow Control ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Splitter Plate ◽  
Hydrodynamic Characteristics ◽  
Control Effect ◽  
Long Time ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

Attaching a splitter plate (SP) on the base of a riser wall is used to control the flow of risers and evaluated by using the CFD technique in this paper. A finite-volume total variation diminishing (TVD) approach for solving incompressible turbulent flow with renormalization group (RNG) turbulence model was used to simulate the hydrodynamic characteristics of the riser system with additional SP for the different aspect ratio of length to diameter L/D. It was shown that the present numerical method has high order of accuracy by comparing with the available experimental and numerical simulation data for typical circular cylinder flow. A riser system attached with SPs of L/D = 0.5∼2.0 for Reynolds number 1000, and 30000 respectively can obviously reduce the lift and drag coefficient and alter the vortex shedding frequency. The mean drag coefficient can be reduced up to 20% and 35% and the maximum lift coefficient can be reduced up to 94% and 97%, for Re = 1000 and 30000, respectively. The lift can be effectively suppressed after a relative long time. L/D = 0.5∼1.0 may be considered as more practical geometries considering the real conditions, which also have good flow control effect.

Aerodynamic Characteristics of a Rectangular Wing With a Tip Clearance in a Channel

1977 ◽  
Vol 44 (4) ◽  
pp. 541-547
Author(s):  
Y. Sugiyama
Keyword(s):  
Boundary Layer ◽  
Aspect Ratio ◽  
Drag Coefficient ◽  
Aerodynamic Characteristics ◽  
Tip Clearance ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Lift And Drag ◽  
Lift And Drag Coefficient ◽  
End Wall

Aerodynamic characteristics of a single, stationary wing, whose tip is in an end-wall boundary layer, are studied experimentally to determine the effects of aspect ratio, tip clearance, angle of attack and end-wall boundary layer. Spanwise distributions of the lift and drag coefficient are derived and interpreted from the data obtained by chordwise pressure measurements on the wing surface. The results indicate that the slope of the lift curve, the angle of zero lift and the drag coefficient reach a maximum at an optimum value of the tip clearance in a certain range of the aspect ratio. Interesting information is also obtained for effects of the end-wall boundary layer on the lift and drag of the wing with a slot.

Computational analysis of the aerodynamic performance of a jet-flap airfoil in transonic flow

2012 ◽  
Vol 226 (6) ◽  
pp. 664-678 ◽  
Author(s):  
V Mantič-Lugo ◽  
G Doulgeris ◽  
A Gohardani ◽  
R Singh
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Angle Of Attack ◽  
Aircraft Design ◽  
Civil Aviation ◽  
Commercial Aircraft ◽  
Angle Variation ◽  
Distributed Propulsion ◽  
Lift And Drag ◽  
Active Flow

The needed shift in next generation aircraft design is expected to bring novel concepts for civil aviation as the jet-flap wing. The aircraft efficiency improvements with the jet-flap wing directs its use for future aircraft designs reinforced by the tendency for more synergistic systems as active flow control, boundary layer ingestion and distributed propulsion, making the jet-flap wing a very suitable option for the latter concept. The analysis carried out in this paper is aimed at the application of the jet-flap wing concept for manoeuvrability and cruise efficiency improvement of an airliner. A 2D computational model of a jet-flapped transonic airfoil is developed in order to assess the jet-flap wing technology for a commercial aircraft at cruise conditions. This paper provides an insight into the parameters that affect the performance of a jet-flap under various flight conditions. To do this, a general parametrical analysis is performed, studying numerically the influences of main flow parameters like Mach number, Reynolds number, angle of attack, jet deflection angle and jet thickness. Changes in pressure distribution and flow circulation around the airfoil yield strong modifications in lift and drag due to jet angle variation. Improvements are encountered in the performance of an airfoil with a jet-flap system compared with a standard airfoil with no jet. Enhancements in lift and reduction in drag, as well as an increase of the lift-to-drag ratio is possible with a proper combination of the jet deflection and the angle of attack of the airfoil. In summary, this paper shows the conditions under which the benefits of the jet-flapped wing, for lift enhancement and manoeuvrability as an active flow control are promising.

Load Control for Turbine Blades: A Non-Traditional Microtab Approach

2002 ◽  
Author(s):  
D. T. Yen Nakafuji ◽  
C. P. van Dam ◽  
J. Michel ◽  
P. Morrison
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Active Flow Control ◽  
Turbine Blades ◽  
Suction Side ◽  
Turbine Rotor ◽  
Load Control ◽  
Drag Forces ◽  
Macro Scale ◽  
Active Flow

Active flow control and load mitigation concepts developed for traditional aeronautical applications have potential to decrease torque, bending and fatigue loads on wind turbine blades and to help increase turbine life. Much of the early work in flow control focused on steady aerodynamic benefits. More recent technologies have focused on unsteady flow control techniques which require a deeper understanding of the underlying flow physics as well as sensors to record the various time-dependent aerodynamic phenomena and fast actuators for control. This paper identifies some developmental control concepts for load mitigation along with a new translational microfabricated tab concept available for active flow and load control on lifting surfaces and explores their applicability for wind turbine rotor blades. Specifically, this paper focuses on experimental results based on an innovative microtab approach for unsteady, active load control. Previous papers on this effort by Yen et al. focused on the multi-disciplinary design methodology and the significant lift enhancement achieved using these micro-scale devices. The current research extends the effort to include dynamic results with discontinuous tab effects, effects on drag, and lower (pressure side) and upper surface (suction side) tab deployment effects for the prototype airfoil as well as for the S809, a representative wind turbine airfoil. Results show that the microtab concept can provide macro-scale load changes and is capable of offering active control of lift and drag forces for load alleviation.

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