Active flow control: techniques and applications

2017 ◽  
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Control Techniques ◽  
Active Flow

scholarly journals Conceptual Design of a Novel Unmanned Ground Effect Vehicle (UGEV) and Flow Control Integration Study

Drones ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Charalampos Papadopoulos ◽  
Dimitrios Mitridis ◽  
Kyros Yakinthos
Keyword(s):  
Flow Control ◽  
Conceptual Design ◽  
Active Flow Control ◽  
Ground Effect ◽  
Passive Flow Control ◽  
Control Techniques ◽  
Passive Flow ◽  
Conceptual Design Phase ◽  
Wide Range ◽  
Active Flow

In this study, the conceptual design of an unmanned ground effect vehicle (UGEV), based on in-house analytical tools and CFD calculations, followed by flow control studies, is presented. Ground effect vehicles can operate, in a more efficient way, over calm closed seas, taking advantage of the aerodynamic interaction between the ground and the vehicle. The proposed UGEV features a useful payload capacity of 300 kg and a maximum range of 300 km cruising at 100 kt. Regarding the aerodynamic layout, a platform which combines the basic geometry characteristics of the blended wing body (BWB), and box wing (BXW) configurations is introduced. This hybrid layout aims to incorporate the most promising features from both configurations, while it enables the UGEV to operate under adverse flight conditions of the atmospheric boundary layer of the earth. In order to enhance the performance characteristics of the platform, both passive and active flow control techniques are studied and incorporated into the conceptual design phase of the vehicle. For the passive flow control techniques, the adaptation of tubercles and wing fences is evaluated. Regarding the active flow control techniques, a wide range of morphing technologies is investigated based on performance and integration criteria. Finally, stability studies are conducted for the proposed platform.

Active Flow Control Techniques on a Stator Compressor Cascade: A Comparison Between Synthetic Jet and Plasma Actuators

2012 ◽  
Author(s):  
Maria Grazia De Giorgi ◽  
Stefania Traficante ◽  
Carla De Luca ◽  
Daniela Bello ◽  
Antonio Ficarella
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Active Flow Control ◽  
Pressure Ratio ◽  
Boundary Layer Separation ◽  
Synthetic Jet ◽  
Plasma Actuators ◽  
Compressor Cascade ◽  
Control Techniques ◽  
Active Flow

In this work a CFD analysis is applied to study the suppression of the boundary layer separation into a highly-loaded subsonic compressor stator cascade, by different active flow control techniques. Active flow control techniques have the potential to delay separation and to increase the pressure ratio. In particular three different techniques have been applied: the actuation by steady jet, by zero net mass flux Synthetic Jet (SJA) and by plasma actuator. Several works have investigated the use of synthetic jet and plasma actuators on the airfoil, but only few studies have compared the effect of these devices. Concerning the synthetic jet actuator, a suction/blowing type boundary condition is used, imposing a prescribed sinusoidal velocity depending on velocity amplitude, jet frequency and jet angle of ejection with respect to the wall. Concerning the plasma actuation, the effect is modeled into numerical flow solvers by adding the paraelectric force that represents the plasma force into the momentum equation. The plasma, generated by Dielectric Barrier Discharge, acts as a momentum source to the boundary layer allowing it to remain attached throughout a larger portion of the airfoil. The time-averaged body force component, acting on the fluid, depends on the frequency and on the applied voltage, the charge density, the electrical field and the dimensional properties of the actuator, like width of the electrodes and gap between the electrodes. Using this numerical model, the effect of plasma actuators to suppress the flow separation over the blade has been investigated, increasing the turbo-machinery performance too. Finally, the comparison between the different actuation devices shows that, reducing the secondary flow structures, each actuation technique beneficially affects the performance of the stator compressor cascade, even if in the steady jet the costs are relevant.

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