Comparative Study of Synthetic Jet Numerical Simulation Methods

2013 ◽  
Vol 275-277 ◽  
pp. 486-490
Author(s):  
Shang Qin Tang ◽  
Chang Qiang Huang
Keyword(s):  
Numerical Simulation ◽  
Moving Boundary ◽  
Active Flow Control ◽  
Velocity Model ◽  
Synthetic Jet ◽  
Domain Model ◽  
Navier Stokes ◽  
Simply Connected Domain ◽  
Boundary Model ◽  
Simply Connected

In order to find the best synthetic jet model for active flow control numerical simulation study, exit velocity model, simply connected domain model and moving boundary model were researched through solving the two dimensional transient Reynolds Average Navier-Stokes(RANS) equations under consistent grid and boundary conditions. Velocity and vortex characteristics of flow field were got. Three models were all able to capture the velocity characteristics compared with experiment data. The moving boundary model can capture the distribution of vortices accurately and was the ideal model for applications, because it considered the spatial distribution and time distribution of diaphragm motion, also because it included the volume change rate of actuator cavity.

Computing Micro Synthetic Jet in Slip Regime With Moving Membrane

2002 ◽  
Author(s):  
A. Rustem Aslan ◽  
Oktay Baysal ◽  
Firat O. Edis
Keyword(s):  
Moving Boundary ◽  
Pressure Field ◽  
Wall Slip ◽  
Synthetic Jet ◽  
Navier Stokes ◽  
Rarefied Flows ◽  
Flow Simulations ◽  
Slip Regime ◽  
Velocity Magnitude ◽  
Primary Focus

A Navier-Stokes (NS) solver for moving and deforming meshes has been modified to investigate numerically the diaphragm-driven flow in and out of two synthetic jet cavity geometries. The piezoelectric-driven diaphragm of the cavity is modeled in a realistic manner as a moving boundary to accurately compute the flow inside the jet cavity. The primary focus of the present paper is to describe the effect of cavity geometry and the wall slip, resulting from the relatively larger Kn number flows associated with micro sized geometries, on the exit jet velocity magnitude. Compressible flow simulations are required for rarefied flows to accurately predict the pressure field. The present computations for the quiescent external flow condition reveal that cavity geometry and the wall slip has an increasing effect on the magnitude of the average jet exit velocity as well as vortex shedding from the orifice.

Numerical Investigations of Active Flow Control Using Synthetic Jets on a Highly Loaded Compressor Stator Cascade

2010 ◽  
Author(s):  
Christoph Gmelin ◽  
Mathias Steger ◽  
Vincent Zander ◽  
Wolfgang Nitsche ◽  
Frank Thiele ◽  
...  
Keyword(s):  
Separation Bubble ◽  
Active Flow Control ◽  
Suction Side ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Navier Stokes ◽  
Compressor Cascade ◽  
Time Resolved ◽  
Laminar Separation ◽  
Zero Net Mass Flux

Time-resolved Reynolds-Averaged Navier-Stokes simulations of a 3D stator compressor cascade are performed. At the design point of the airfoil under investigation, pronounced secondary flow effects are observed. Strong corner vortices emerge from the casing walls and the flow separates from the blade suction side towards the trailing edge. Transition from laminar to turbulent flow occurs within a laminar separation bubble. Using a commercial CFD software, the influence of the spatial resolution is investigated by means of a spanwise coarsening and refinement of the created mesh. Zero net mass flux synthetic jet actuation is used to control the separated regions. The work presents a variation of the temporal discretization and an analysis of the driving parameters of the actuation.

Effective Range of Micro and Synthetic Jets for Flow Control

2005 ◽  
Author(s):  
Mehti Koklu ◽  
Nurhak Erbas ◽  
Oktay Baysal
Keyword(s):  
Flow Control ◽  
Moving Boundary ◽  
Rarefied Gas ◽  
Oscillation Amplitude ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Navier Stokes ◽  
Rarefied Gas Flows ◽  
Design Variables ◽  
Primary Focus

Effectiveness of two-dimensional synthetic jet is studied using numerical simulations. A Navier-Stokes (NS) solver for moving and deforming meshes has been modified to investigate numerically the diaphragm-driven flow in and out of two synthetic jet cavity geometries. Compressible flow simulations are required for rarefied gas flows to accurately predict the micro flow field. The solver is modified to accommodate slip wall boundary condition proposed in literature for micro scale flow problems. The piezoelectric-driven diaphragm of the cavity is modeled in a realistic manner as a moving boundary to accurately compute the flow inside the jet cavity. The primary focus of the proposed paper will be on the analysis of the design space determined by the geometric and flow-type design variables that identify the effectiveness of the synthetic jet by means of the orifice jet velocity and local jet momentum rate. The design variables are the membrane oscillation frequency (f), membrane oscillation amplitude (A), orifice width (d), and membrane width (W). The present computations for jet discharging into quiescent medium reveal that these variables have determining effects on the flow control parameters, which are the jet exit velocity, local momentum rate, as well as vortex shedding from the orifice.

Use of Micro Synthetic Jet Actuators for Boundary Layer Flow Control

2009 ◽  
Vol 74 ◽  
pp. 157-160
Author(s):  
Jing Chuen Lin ◽  
An Shik Yang ◽  
Li Yu Tseng
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Turbulent Flows ◽  
Boundary Layer Flow ◽  
Moving Boundary ◽  
Active Flow Control ◽  
Flow Characteristics ◽  
Synthetic Jet ◽  
Layer Flow ◽  
Active Flow

The main purpose of active flow control research is to develop a cost-effective technology that has the potential for inventive advances in aerodynamic performance and maneuvering compared to conventional approaches. It can be essential to thoroughly understand the flow characteristics of the formation and interaction of a synthetic jet with external crossflow before formulating a practicable active flow control strategy. In this study, the theoretical model used the transient three-dimensional conservation equations of mass and momentum for compressible, isothermal, turbulent flows. The motion of a movable membrane plate was also treated as the moving boundary by prescribing the displacement on the plate surface. The predictions by the computational fluid dynamics (CFD) code ACE+® were compared with measured transient phase-averaged velocities of Rumsey et al. for software validation. The CFD software ACE+® was utilized for numerical calculations to probe the time evolution of the development process of the synthetic jet and its interaction within a turbulent boundary layer flow for a complete actuation cycle.

Experimental and numerical studies of synthetic jets driven by a dual-diaphragm piezoelectric actuator

2009 ◽  
Vol 223 (6) ◽  
pp. 1393-1400 ◽  
Author(s):  
A-S Yang ◽  
J-J Ro ◽  
W-H Chang
Keyword(s):  
Moving Boundary ◽  
Active Flow Control ◽  
Vortex Pair ◽  
Ambient Air ◽  
Lateral Spreading ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Visualization System ◽  
Air Jet ◽  
Centre Line

The applications of piezoelectric synthetic jet actuators have shown great potential as active flow control devices. The objective of this study is to investigate the flow phenomenon of a synthetic jet generated by a dual-diaphragm piezo-driven actuator. In this analysis, the computational approach adopted unsteady three-dimensional conservation equations of mass and momentum for examining the development process of synthetic jets. The moving boundary was also treated to represent the motion of the piezo diaphragm. Experimentally, a flow visualization system was employed to acquire the particle-streak images scattered from red fluorescent spheres for observing the synthetic jet flow. The jet velocity along the centre-line was also measured by using a hot-wire anemometer. The system test results demonstrated a satisfactory functioning of the actuator for producing synthetic jets. The predictions were then compared with the visualized particle-streak images and the measured centre-line velocity of the synthetic jet to validate the computer software. In the near-field, both simulation results and experimental observations revealed the time-cyclical formation and advection of a vortex pair in a full sinusoidal actuation cycle at an operating frequency of 4 Hz. When the vortex pair travelled well downstream, the ambient air from the vicinity of the slot was entrained into the cavity of the actuator. However, the overall far-field flow pattern, characterized by longitudinal decay of the centre-line velocity and lateral spreading, resembled a conventional continuous air-jet in essence.

PANS Study of the Flow Around an Oscillating, Simplified Truck Cabin With Flow Control

2017 ◽  
Author(s):  
G. Minelli ◽  
S. Krajnović ◽  
B. Basara
Keyword(s):  
Flow Control ◽  
Stokes Equations ◽  
Numerical Study ◽  
Active Flow Control ◽  
Synthetic Jet ◽  
Navier Stokes ◽  
Dynamic Configuration ◽  
Navier Stokes Equations ◽  
Recirculation Bubble ◽  
Yaw Angle

This work presents an application of the Partially-Averaged Navier-Stokes equations for an external vehicle flow. In particular, the flow around a generic truck cabin is simulated. The PANS method is first validated against experiments and resolved LES on two static cases. As a consequence, PANS is used to study the effect of an active flow control (AFC) on a dynamic oscillating configuration. The oscillation of the model represents a more realistic ground vehicle flow, where gusts (of different nature) define the unsteadiness of the incoming flow. In the numerical study, the model is forced to oscillate with a yaw angle 10° > β > −10° and a non-dimensional frequency St = fW/Uinf = 0.1. The effect of the periodic motion of the model is compared with the quasi-steady flow condition. At a later stage, the dynamic configuration is actuated by means of a synthetic jet boundary condition. Overall, the effect of the actuation is beneficial. The actuation of the AFC decreases drag, stabilises the flow and reduces the size of the side recirculation bubble.

Study of a Crossflow over a Zero-Net-Mass-Flux Synthetic Jet Driven by a Vibrating Diaphragm

2011 ◽  
Vol 27 (4) ◽  
pp. 503-509 ◽  
Author(s):  
L.-Y. Tseng ◽  
A.-S. Yang ◽  
J.-C. Lin
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Turbulent Flows ◽  
Mass Flux ◽  
Moving Boundary ◽  
Active Flow Control ◽  
Flow Characteristics ◽  
Synthetic Jet ◽  
Computational Domain ◽  
Zero Net Mass Flux

ABSTRACTMiniature synthetic jet actuators are low operating power, zero-net-mass-flux and very compact devices which have demonstrated their capability in modifying the subsonic flow characteristics for boundary layer flow control. In order to improve the design active flow control systems, the present study aims to examine the formation and interaction of unsteady flowfield of a synthetic jet with external crossflow. In view of a single synthetic jet emitting into a turbulent boundary layer crossflow via a circular orifice, the theoretical model utilized the transient three-dimensional conservation equations of mass and momentum for compressible, turbulent flows with a negligible temperature variation over the computational domain. The motion of a movable membrane plate was also treated as the moving boundary by prescribing the displacement on the plate surface. The predictions by the computational fluid dynamics (CFD) software ACE+®were compared with the measured transient phase-averaged velocities in literature for code validation. The predictions showed the time evolution of the large vortical structure originating from the jet orifice and its successive interaction with the crossflow to change the flow structure inside the boundary layer.

scholarly journals TWO-DIMENSIONAL INCOMPRESSIBLE IDEAL FLOWS IN A NONCYLINDRICAL MATERIAL DOMAIN

2007 ◽  
Vol 17 (12) ◽  
pp. 2035-2053 ◽  
Author(s):  
F. Z. FERNANDES ◽  
M. C. LOPES FILHO
Keyword(s):  
Weak Solution ◽  
Euler Equations ◽  
Connected Domain ◽  
Moving Boundary ◽  
Two Dimensional ◽  
Noncylindrical Domain ◽  
Simply Connected Domain ◽  
Initial Vorticity ◽  
Simply Connected ◽  
Incompressible Euler

The purpose of this work is to prove the existence of a weak solution of the two-dimensional incompressible Euler equations on a noncylindrical domain consisting of a smooth, bounded, connected and simply connected domain undergoing a prescribed motion. We prove the existence of a weak solution for initial vorticity in Lp, for p > 1. This work complements a similar result by C. He and L. Hsiao, who proved existence assuming that the flow velocity is tangent to the moving boundary, see Ref. 6.

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