Download or read book Modeling of D C Motor Driven Synthetic Jet Acutators for Flow Separation Control written by Ashwin Kumar Balasubramanian and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to present a theoretical study of the compressibility effects on the performance of an electric D/C motor driven synthetic jet actuator for flow separation control. Hot wire anemometer experiments were conducted to validate the jet exit velocities predicted by the theoretical model. The optimal jet exit velocity required to achieve maximum flow reattachment at reasonable blowing momentum coefficients is predicted. A dynamic electro-acoustic model of the D/C motor driven actuator is developed to accurately predict its performance and efficiency. This model should help formulate a feedback optimal control strategy for real-time flow control using an array of actuators. This model is validated by comparing with hot wire anemometer experiments conducted under similar conditions. The effects of geometric parameters like the slot width, slot geometry, and cavity volume on the performance of the actuator are also tested using this model.

Download or read book Performance Modelling of Synthetic Jet Actuators for Flow Separation Control written by and published by . This book was released on 2006 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthetic Jet Actuation Modeling Actuator Development and Application to Separation Control written by and published by . This book was released on 2004 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents an investigation of synthetic jet actuation for separation control over wings/airfoils, in steady and unsteady flows, the development of high-power, compact synthetic jet actuators (SJA) for flow separation control, the modeling and control of such actuators and the modeling and control of the resulting SJA-controlled aerodynamics and wing/airfoil, respectively. The developed actuator is compact enough to fit in the interior of a NACAOOl5 profiled wing with a chord of 0.375 m. Test bench experiments showed that the multi-piston actuator array was capable of producing exit velocities of up to 90 rn/s for an actuator frequency of 130 Hz. The actuator was placed in a NACA 0015 wing and tested in a wind tunnel. An experimental investigation into the effects of a synthetic jet actuator on the performance of the wing, in steady flow, is described. Emphasis is placed on the capabilities of the actuator to control the separation of the flow over the wing at high angles of attack. The investigation included the use of force balance measurements, on -surface flow visualization with oil and tufts, off-surface flow visualizations with smoke, surface pressure distribution measurements and wake surveys.

Download or read book Development of High power Compact Synthetic Jet Actuators for Flow Separation Control written by Jose Luis Gilarranz and published by . This book was released on 2001 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lumped Element Modeling of Piezoelectric driven Synthetic Jet Actuators for Active Flow Control written by Quentin Gallas and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: This thesis presents a lumped element model of a piezoelectric-driven synthetic-jet actuator. A synthetic jet, also known as a zero net mass-flux device, uses a vibrating diaphragm to generate an oscillatory flow through a small orifice or slot. In lumped element modeling, the individual components of a synthetic jet are modeled as elements of an equivalent electrical circuit using conjugate power variables. The frequency response function of the circuit is derived to obtain an expression for the volume flow rate through the orifice per applied voltage across the piezoceramic. The circuit is analyzed to provide physical insight into the dependence of the device behavior on geometry and material properties. Methods to estimate the model parameters are discussed along with pertinent model assumptions, and experimental verification is presented of the lumped parameter models. In addition, two prototypical synthetic jet actuators are built and tested. Very good agreement is obtained between the predicted and measured frequency response functions.

Download or read book Active Flow Separation Control Using Synthetic Jet Actuators written by Preetham P. Rao and published by . This book was released on 2000 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Control of Internal Flow Separation Using Synthetic Jet Actuators written by M. Amitay and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow Control Simulation with Synthetic and Pulsed Jet Actuator written by Sol Keun Jee and published by . This book was released on 2010 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two active flow control methods are investigated numerically to understand the mechanism by which they control aerodynamics in the presence of severe flow separation on an airfoil. In particular, synthetic jets are applied to separated flows generated by additional surface feature (the actuators) near the trailing edge to obtain Coanda-like effects, and an impulse jet is used to control a stalled flow over an airfoil. A moving-grid scheme is developed, verified and validated to support simulations of external flow over moving bodies. Turbulent flow is modeled using detached eddy simulation (DES) turbulence models in the CFD code CDP (34) developed by Lopez (54). Synthetic jet actuation enhances turbulent mixing in flow separation regions, reduces the size of the separation, deflects stream lines closer to the surface and changes pressure distributions on the surface, all of which lead to bi-directional changes in the aerodynamic lift and moment. The external flow responds to actuation within about one convective time, which is significantly faster than for conventional control surfaces. Simulation of pitching airfoils shows that high-frequency synthetic jet affects the flow independently of the baseline frequencies associated with vortex shedding and airfoil dynamics. These unique features of synthetic jets are studied on a dynamically maneuvering airfoil with a closed-loop control system, which represents the response of the airfoil in wind-tunnel experiments and examines the controller for a rapidly maneuvering free-flight airfoil. An impulse jet, which is applied upstream of a nominal flow separation point, generates vortices that convect downstream, interact with the separating shear layer, dismantle the layer and allow following vortices to propagate along the surface in the separation region. These following vortices delay the separation point reattaching the boundary layer, which returns slowly to its initial stall condition, as observed in wind-tunnel experiments. A simple model of the impulse jet actuator used herein is found to be sufficient to represent the global effects of the jet on the stalled flow because it correctly represents the momentum injected into the flow.

Download or read book Development of Design Tools for Flow control Actuators written by Jose Mathew and published by . This book was released on 2003 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lumped Element Modeling of Piezoelectric Driven Synthetic Jet Actuators written by and published by . This book was released on 2002 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents a lumped element model of a piezoelectric-driven synthetic jet actuator. A synthetic jet, also known as a zero net mass-flux device, uses a vibrating diaphragm to generate an oscillatory flow through a small orifice or slot. In lumped element modeling (LEM), the individual components of a synthetic jet are modeled as elements of an equivalent electrical circuit using conjugate power variables. The frequency response function of the circuit is derived to obtain an expression for Q(sub out)/V(sub AC), the volume flow rate per applied voltage. The circuit is analyzed to provide physical insight into the dependence of the device behavior on geometry and material properties. Methods to estimate the model parameters are discussed, and experimental verification is presented. In addition, the model is used to estimate the performance of two prototypical synthetic jets, and the results are compared with experiment.

Download or read book A Reduced Order Model for Efficient Simulation of Synthetic Jet Actuators written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-29 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new reduced-order model of multidimensional synthetic jet actuators that combines the accuracy and conservation properties of full numerical simulation methods with the efficiency of simplified zero-order models is proposed. The multidimensional actuator is simulated by solving the time-dependent compressible quasi-1-D Euler equations, while the diaphragm is modeled as a moving boundary. The governing equations are approximated with a fourth-order finite difference scheme on a moving mesh such that one of the mesh boundaries coincides with the diaphragm. The reduced-order model of the actuator has several advantages. In contrast to the 3-D models, this approach provides conservation of mass, momentum, and energy. Furthermore, the new method is computationally much more efficient than the multidimensional Navier-Stokes simulation of the actuator cavity flow, while providing practically the same accuracy in the exterior flowfield. The most distinctive feature of the present model is its ability to predict the resonance characteristics of synthetic jet actuators; this is not practical when using the 3-D models because of the computational cost involved. Numerical results demonstrating the accuracy of the new reduced-order model and its limitations are presented.Yamaleev, Nail K. and Carpenter, Mark H.Langley Research CenterACTIVE CONTROL; JET FLOW; FINITE DIFFERENCE THEORY; NAVIER-STOKES EQUATION; ACTUATORS; CAVITY FLOW; THREE DIMENSIONAL MODELS; COMPUTATIONAL GRIDS; TIME DEPENDENCE...

Download or read book Performance Modelling of Synthetic Jet Actuators for Flow Seperation Control written by Hui Tang and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Compensation of Nonlinear Actuators for Flight Control Applications written by Dipankar Deb and published by Springer Nature. This book was released on 2021-07-22 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a basic understanding of adaptive control and its applications in Flight control. It discusses the designing of an adaptive feedback control system and analyzes this for flight control of linear and nonlinear aircraft models using synthetic jet actuators. It also discusses control methodologies and the application of control techniques which will help practicing flight control and active flow control researchers. It also covers modelling and control designs which will also benefit researchers from the background of fluid mechanics and health management of actuation systems. The unique feature of this book is characterization of synthetic jet actuator nonlinearities over a wide range of angles of attack, an adaptive compensation scheme for such nonlinearities, and a systematic framework for feedback control of aircraft dynamics with synthetic jet actuators.

Download or read book Performance Modelling of Synthetic Jet Actuators for Flow Seperation Control written by Hui Tang and published by . This book was released on 2006 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling and Computation of a Synthetic Jet Actuator for Flow and Aeroelastic Control written by Schober Stephen J. and published by . This book was released on 2006 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Compact High power Synthetic Jet Actuators for Slow Separation Control written by J. L. Gilarranz and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Synthetic Jet Actuators for Active Flow Control written by Rahul Sekhri and published by . This book was released on 2005 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthetic jet actuators (SJAs) are one of the newly developed actuators that have demonstrated great potentials in active flow applications, particularly in closed-loop flow controls. The SJA contains a piezoelectric membrane in a cavity, which vibrates and generates a periodic jet at the exit of the cavity through an orifice that is mounted flush with the solid wall of the flow field. In order to design the feedback control laws, it is crucial to be able to quantitatively capture the dynamics of SJAs. In this thesis, the dynamics of SJAs with six different orifice sizes are experimentally investigated. A synthesis using system identification for the purpose of constructing mathematical models of these zero mass-flux actuators is offered. The experimental study includes two output parameters, the acoustic sound pressure generated by the SJA and the mechanical membrane vibration of the SJA. State-space models for these outputs (sound pressure and mechanical vibration) are developed as a function of orifice size. These results form a foundation for future intelligent design of SJAs. A preliminary result of flow-velocity measurement is given, and finally the contributions of this entire work and future recommendations are discussed as part of the conclusions.