Detached eddy simulation of a synthetic jet for flow control

2008 ◽  
Vol 222 (5) ◽  
pp. 373-380 ◽  
Author(s):  
N Qin ◽  
H Xia
Keyword(s):  
Flow Control ◽  
Synthetic Jet ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

scholarly journals Numerical Investigation on Unsteady Separation Flow Control in an Axial Compressor Using Detached-Eddy Simulation

2019 ◽  
Vol 9 (16) ◽  
pp. 3298 ◽  
Author(s):  
Mingming Zhang ◽  
Anping Hou
Keyword(s):  
Flow Control ◽  
Excitation Frequency ◽  
Axial Compressor ◽  
Separation Flow ◽  
Pressure Side ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Unsteady Separation ◽  
Inherent Frequency ◽  
The Impact

Unsteady excitation has proved its effectiveness in separation flow control and has been extensively studied. It is observed that disordered shedding vortices in compressors can be controlled by unsteady excitation, especially when the excitation frequency coincides with the frequency of the shedding vortex. Furthermore, former experimental results indicated that unsteady excitation at other frequencies also had an impact on the structure of shedding vortices. To investigate the impact of excitation frequency on vortex shedding structure, the Detached-Eddy Simulation (DES) method was applied in the simulation of shedding vortex structure under unsteady excitations at different frequencies in an axial compressor. Effectiveness of the DES method was proved by comparison with URANS results. The simulation results showed a good agreement with the former experiment. The numerical results indicated that the separation flow can be partly controlled when the excitation frequency coincided with the unsteady flow inherent frequency. It showed an increase in stage performance under the less-studied separation flow control by excitation at a certain frequency of pressure side shedding vortex. Compared with other frequencies of shedding vortices, the frequency of pressure side shedding vortex was less sensitive to mass-flow variation. Therefore, it has potential for easier application on flow control in industrial compressors.

scholarly journals Detached Eddy-Simulation of Delta-Wing Post-Stall Flow Control

2018 ◽  
Vol 29 ◽  
pp. 46-57 ◽  
Author(s):  
Andrei Buzica ◽  
Manuel Biswanger ◽  
Christian Breitsamter
Keyword(s):  
Flow Control ◽  
Delta Wing ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

Numerical Analysis of Sweeping Jets for Active Flow Control Application

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Shawn Aram
Keyword(s):  
Flow Control ◽  
Shear Layer ◽  
Active Flow Control ◽  
Three Dimensional ◽  
Streamwise Velocity ◽  
Detached Eddy Simulation ◽  
Free Shear Layer ◽  
Separation Line ◽  
Eddy Simulation ◽  
Wide Range

Abstract It has become apparent recently that the fluidic oscillators, also known as sweeping jets, can be used to create a combination of steady (streamwise vortices) and unsteady (spanwise vortices) forcing mechanisms which have the potential to fulfill many of the promises of active separation control. The fluidic oscillators contain no moving parts, but produce an unsteady component via a natural feedback loop inherent to their geometry. The oscillations are entirely self-induced and self-sustaining. Their simple and robust design and their effectiveness over a wide range of flow conditions make them more attractive than other flow control devices, such as synthetic jets and plasma actuators. Figure 1 shows the instantaneous jet generated in quiescent environment using the Improved Delayed Detached Eddy Simulation (IDDES) model, where the Large Eddy Simulation (LES) branch of the IDDES model is able to capture the turbulence structures properly. An instantaneous iso-surface of vorticity magnitude, colored by streamwise velocity for flow over a wall-mounted hump is depicted in Figure 2. As expected, a massive flow separation occurs behind the hump in the uncontrolled condition (Figure 2 (a)), with a nearly two-dimensional free shear layer at the edge of the separation line. Breakdown of the shear layer by an array of sweeping jets located slightly downstream of the separation line is seen in Figure 2 (b), which is followed by the elimination of the separation region behind hump. The three-dimensional structures generated by the sweeping jets are smaller and closer to the hump wall than those produced by the steady jets shown in Figure 2 (c). Presence of a large region of reversed flow near the hump wall in its aft section is also seen in the case of the steady jet. This study indicates a superior effectiveness of sweeping jets on separated flows.

DETACHED-EDDY SIMULATION FOR SYNTHETIC JETS WITH MOVING BOUNDARIES

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1429-1434 ◽  
Author(s):  
HAO XIA ◽  
NING QIN
Keyword(s):  
Boundary Layers ◽  
Moving Boundary ◽  
Turbulent Boundary Layers ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Moving Boundaries ◽  
Time Dependent ◽  
Jet Flows ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

A Detached-Eddy Simulation (DES) with moving boundaries has been developed and applied to synthetic jet flows. Complex unsteady flow patterns of the flows were revealed from the simulation. Comparisons between the simulation and experiments showed reasonably good agreements, which indicates that, as a hybrid RANS/LES method, DES is capable of handling unsteady separations with turbulent boundary layers and time-dependent moving boundary conditions.

Effect of Unsteady Wake on Flow Control of the Low-Pressure High-Lift Cascade with Synthetic Jet

2012 ◽  
Vol 588-589 ◽  
pp. 1790-1793
Author(s):  
Yong Hui Xie ◽  
Huan Cheng Qu ◽  
Hai Yu He
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Flow Separation ◽  
Low Pressure ◽  
Aerodynamic Performance ◽  
Synthetic Jet ◽  
High Lift ◽  
Eddy Simulation ◽  
Unsteady Wake ◽  
Large Eddy

The flow separation is susceptible to appear and is known to affect the aerodynamic performance of the low-pressure high-lift cascade. Large Eddy Simulation was adopted in the present work and the periodic moving bar was employed to simulate the unsteady wake upstream of the blade. The flow control of the synthetic jet with unsteady wake was investigated in detail. The upstream wake increased the turbulent level of the boundary layer of the cascade. The synthetic jet got a better control under the effect of the upstream wake.

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