Numerical Investigation of an Elastomer-Piezo-Adaptive Blade for Active Flow Control of a Nonsteady Flow Field Using Fluid–Structure Interaction Simulations

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Tien Dat Phan ◽  
Patrick Springer ◽  
Robert Liebich
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Leading Edge ◽  
Material Behavior ◽  
Fluid Structure ◽  
Numerical Investigations ◽  
Pulsed Detonation ◽  
Stator Blade ◽  
Suitable Concept ◽  
Active Flow

In order to prevent critical effects due to pulsed detonation propulsion, e.g., incidence fluctuations, an elastomer-piezo-adaptive stator blade with a deformable front part is developed. Numerical investigations with respect to the interaction of fluid and structure including the piezoelectric properties and the hyperelastic material behavior of an elastomer membrane are conducted in order to investigate the concept of the elastomer-piezo-adaptive blade for developing the best suitable concept for subsequent experiments with a stator cascade in a wind tunnel. Results of numerical investigations of the structure-dynamic and fluid mechanical behavior of the elastomer-piezo-adaptive blade by using a novel fluid–structure-piezoelectric-elastomer-interaction simulation (FSPEI simulation) show that the latent danger of a laminar flow separation at the leading edge at incidence fluctuations can be prevented by using an adaptive blade. Therefore, the potential of the concept of the elastomer-piezo-adaptive blade for active flow control is verified. Furthermore, it is essential to consider the interactions between fluid and structure of the transient FSPEI simulations, since not only the deformation of the adaptive blade affects the flow around the blade, the flow has a significant effect on the dynamic behavior of the adaptive blade, as well.

Comparison of Two Active Flow Control Mechanisms of Pure Blowing and Pure Suction on a Pitching NACA0012 Airfoil at Reynolds Number of 1 × 106

2018 ◽  
Author(s):  
Ehsan Asgari ◽  
Mehran Tadjfar
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Active Flow Control ◽  
Hysteresis Loops ◽  
Leading Edge ◽  
Control Mechanisms ◽  
Airfoil Surface ◽  
Naca0012 Airfoil ◽  
Maximum Angle ◽  
Active Flow

In this study, we have applied and compared two active flow control (AFC) mechanisms on a pitching NACA0012 airfoil at Reynolds number of 1 × 106 using 2-D computational fluid dynamics (CFD). These mechanisms are continuous blowing and suction which are applied separately on the airfoil which pitches around its quarter-chord in a sinusoidal motion. The location for suction and blowing was determined in our previous study based on the formation of a counter clock-wise vortex near the leading-edge. In our current study, we have compared the effectiveness of pure blowing and pure suction in suppressing the dynamic stall vortex (DSV) which is the main contributor to the drag increase, particularly near the maximum angle of attack (AOA) and in early downstroke motion. The blowing/suction slot is considered as a dent on the airfoil surface which enables the AFC to perform in a tangential manner. This configuration would allow blowing jet to penetrate further downstream and was shown to be more effective compared to a cross-flow orientation. We have compared the two aforementioned mechanisms in terms of hysteresis loops of lift and drag coefficients and have demonstrated the dynamics of flow in controlled and uncontrolled situations.

Experimental Investigations on the Efficiency of Active Flow Control in a Compressor Cascade With Periodic Non-Steady Outflow Conditions

2017 ◽  
Author(s):  
Marcel Staats ◽  
Wolfgang Nitsche
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Flow Separation ◽  
Active Flow Control ◽  
Experimental Investigations ◽  
Compressor Cascade ◽  
Steady Regime ◽  
Stator Blade ◽  
Active Flow ◽  
The Impact

We present results of experiments on a periodically unsteady compressor stator flow of the type which would be expected in consequence of pulsed combustion. A Reynolds number of Re = 600000 was used for the investigations. The experiments were conducted on the two-dimensional low-speed compressor testing facility in Berlin. A choking device downstream the trailing edges induced a periodic non-steady outflow condition to each stator vane which simulated the impact of a pressure gaining combuster downstream from the last stator. The Strouhal number of the periodic disturbance was Sr = 0.03 w.r.t. the stator chord length. Due to the periodic non-steady outflow condition, the flow-field suffers from periodic flow separation phenomena, which were managed by means of active flow control. In our case, active control of the corner separation was applied using fluidic actuators based on the principle of fluidic amplification. The flow separation on the centre region of the stator blade was suppressed by means of a fluidic blade actuator leading to an overall time-averaged loss reduction of 11.5%, increasing the static pressure recovery by 6.8% while operating in the non-steady regime. Pressure measurements on the stator blade and the wake as well as PIV data proved the beneficial effect of the active flow control application to the flow field and the improvement of the compressor characteristics. The actuation efficiency was evaluated by two figures of merit introduced in this contribution.

Organization of Cylinder Wake Using a Splitter-Plate Active Flow Control

2010 ◽  
Author(s):  
Chris Weiland ◽  
Pavlos Vlachos
Keyword(s):  
Circular Cylinder ◽  
Flow Control ◽  
Strouhal Number ◽  
Active Flow Control ◽  
Leading Edge ◽  
Splitter Plate ◽  
Cylinder Wake ◽  
Time Resolved ◽  
Image Velocimetry ◽  
Active Flow

Time Resolved Digital Particle Image Velocimetry (TRDPIV) was used in conjunction with spectral analysis to study the effects of Leading Edge Blowing (LEB) flow control on the near-wake of a circular cylinder. The airfoil was placed 1.9 circular cylinder diameters downstream, effectively acting as a splitter plate. Spectral measurements of the TRDPIV results indicated that the presence of the airfoil decreased the Strouhal number from 0.19 to 0.12 as anticipated. When activated the LEB jet organized the circular cylinder wake, effectively neutralizing the effect of the splitter plate and modifying the wake so as to return the Strouhal number to 0.19. Thus the circular cylinder wake returned to its normal shedding frequency, even in the presence of the airfoil. Evidence presented in this study supports the notion that the LEB jet directly excites the circular cylinder shear layers causing instability, roll up, and subsequent vortex shedding.

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.

Active flow control concepts and application opportunities

2017 ◽  
Vol 89 (5) ◽  
pp. 725-729 ◽  
Author(s):  
Heribert Bieler
Keyword(s):  
Flow Control ◽  
Skin Friction ◽  
High Speed ◽  
Active Flow Control ◽  
Leading Edge ◽  
Design Activity ◽  
Content Type ◽  
Low Speed ◽  
Significant Step ◽  
Active Flow

Purpose Aerodynamics drives the aircraft performance and, thus, influences fuel consumption and environmental compatibility. Further, optimization of aerodynamic shapes is an ongoing design activity in industrial offices; this will lead to incremental improvements. More significant step changes in performance are not expected from pure passive shape design. However, active flow control is a key technology, which has the potential to realize a drastic step change in performance. Flow control targets two major goals: low speed performance enhancements mainly for start and landing phase via control of separation and drag reduction at high speed conditions via skin friction and shock wave control. Design/methodology/approach This paper highlights flow control concepts and Airbus involvements for both items. To mature flow control systematically, local applications of separation control technology are of major importance for Airbus. In parallel, but at lower maturity level, investigations are ongoing to reduce the turbulent skin friction at cruise. A popular concept to delay separation at low speed conditions is the implementation of jet actuation control systems flush mounted to the wall of aerodynamic components. Findings In 2006, DLR (in collaboration with universities Berlin, Braunschweig and industrial partner Airbus) started to study active flow control for separation delay towards application. Based on basic proof of concepts (achieved in national projects), further flow control hardware developments and wind tunnel and lab testing took place in European funded projects. Originality/value Significant lift enhancements were realized via flow control applied to the wing leading edge and the flap.

Design and cost analysis of integration of fluidic oscillator into a flap structure

2017 ◽  
Vol 232 (16) ◽  
pp. 2978-2988 ◽  
Author(s):  
J Li ◽  
J Colton
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Leading Edge ◽  
Control Technology ◽  
Fluidic Oscillator ◽  
Transport Aircraft ◽  
High Production ◽  
Manufacturing Assembly ◽  
The Cost ◽  
Active Flow

Integration of active flow control technology into civil transport aircraft is a highly desired objective due to the potential reductions in part count, weight, and recurring manufacturing costs. This study develops an optimal design for integrating a fluidic oscillator into the leading-edge of a trailing-edge flap structure on a civil transport aircraft. The design incorporates design specifications set by members of the aerospace industry, robust design methodologies, and simulation studies to create three separate designs that can be mass-produced. An analysis of the manufacturing, assembly, material, and weight reveals the cost of the design with respect to its production rate, which ranges from about $4090 per aircraft for low-production volumes to about $2600 per aircraft for high-production volumes. As a result, this study provides a basis for the design of manufacturing and assembly techniques to integrate active flow control technology into civil transport aircraft.

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