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Computational Study of a NACA4415 ai...

Lopez Mejia, Omar Dario,

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Computational Study of a NACA4415 airfoil using synthetic jet control /

Record Type:	Electronic resources : Monograph/item
Title/Author:	Computational Study of a NACA4415 airfoil using synthetic jet control // Omar Dario Lopez Mejia.
Author:	Lopez Mejia, Omar Dario,
Description:	1 electronic resource (215 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 72-08, Section: B.
Contained By:	Dissertations Abstracts International72-08B.
Subject:	Mechanics. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3439392
ISBN:	9781124445465

Computational Study of a NACA4415 airfoil using synthetic jet control /
Lopez Mejia, Omar Dario,

Computational Study of a NACA4415 airfoil using synthetic jet control /Omar Dario Lopez Mejia. - 1 electronic resource (215 pages)

Source: Dissertations Abstracts International, Volume: 72-08, Section: B.

Synthetic jet actuators for flow control applications have been an active topic of experimental research since the 90's. Numerical simulations have become an important complement of that experimental work, providing detailed information of the dynamics of the controlled flow. This study is part of the AVOCET (Adaptive VOrticity Control Enabled flighT) project and is intended to provide computational support for the design and evaluation of closed-loop flow control with synthetic jet actuators for small scale Unmanned Aerial Vehicles (UAVs). The main objective is to analyze active flow control of a NACA4415 airfoil with tangential synthetic jets via computational modeling. A hybrid Reynolds-Averaged Navier-Stokes/Large Eddy Simulation (RANS/LES) turbulent model (called Delayed Detached-Eddy Simulation-DDES) was implemented in CDP, a kinetic energy conserving Computational Fluid Dynamics (CFD) code. CDP is a parallel unstructured grid incompressible flow solver, developed at the Center for Integrated Turbulence Simulations (CITS) at Stanford University. Two models of synthetic jet actuators have been developed and validated. The first is a detailed model in which the flow in and out of the actuator cavity is modeled. A second less costly model (RSSJ) was also developed in which the Reynolds stress produced by the actuator is modeled, based on information from the detailed model. Several static validation test cases at different angle of attack with modified NACA4415 and Dragon Eye airfoils were performed. Numerical results show the effects of the actuators on the vortical structure of the flow, as well as on the aerodynamic properties. The main effect of the actuation on the time averaged vorticity field is a bending of the separation shear layer from the actuator toward the airfoil surface, resulting in changes in the aerodynamic properties. Full actuation of the suction side actuator reduces the pitching moment and increases the lift force, while the pressure side actuator increases the pitching moment and reduces the lift force. These observations are in agreement with experimental results. The effectiveness of the actuator is measured by the change in the aerodynamic properties of the airfoil in particular the lift (Δ Cl) and moment (ΔCm) coefficients. Computational results for the actuator effectiveness show very good agreement with the experimental values (over the range of -2° to 10°). While the actuation modifies the global pressure distribution, the most pronounced effects are near the trailing edge in which a spike in the pressure coefficient (Cp) is observed. The local reduction of Cp, for both the suction side and pressure side actuators, at [special characters omitted] = 0.96 (the position of the actuators) is about 0.9 with respect to the unactuated case. This local reduction of the pressure is associated with the trapped vorticity and flow acceleration close to the trailing edge. The RSSJ model is designed to capture the synthetic jet time averaged behavior so that the high actuation frequencies are eliminated. This allows the time step to be increased by a factor of 5. This ad hoc model is also tested in dynamic simulations, in which its capacity to capture the detail model average performance was demonstrated. Finally, the RSSJ model was extended to a different airfoil profile (Dragon Eye) with good results.

English

ISBN: 9781124445465Subjects--Topical Terms:

525881
Mechanics.
Subjects--Index Terms:

Airfoils

Computational Study of a NACA4415 airfoil using synthetic jet control /
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040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a Lopez Mejia, Omar Dario, $e author. $3 3815719
245 1 0 $a Computational Study of a NACA4415 airfoil using synthetic jet control / $c Omar Dario Lopez Mejia.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2009
300 $a 1 electronic resource (215 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 72-08, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisors: Moser, Robert D. Committee members: Bishop, Robert; Bogard, David; Ezekoye, Ofodike; Raman, Venkatramanan.
502 $b Ph.D. $c The University of Texas at Austin $d 2009.
520 $a Synthetic jet actuators for flow control applications have been an active topic of experimental research since the 90's. Numerical simulations have become an important complement of that experimental work, providing detailed information of the dynamics of the controlled flow. This study is part of the AVOCET (Adaptive VOrticity Control Enabled flighT) project and is intended to provide computational support for the design and evaluation of closed-loop flow control with synthetic jet actuators for small scale Unmanned Aerial Vehicles (UAVs). The main objective is to analyze active flow control of a NACA4415 airfoil with tangential synthetic jets via computational modeling. A hybrid Reynolds-Averaged Navier-Stokes/Large Eddy Simulation (RANS/LES) turbulent model (called Delayed Detached-Eddy Simulation-DDES) was implemented in CDP, a kinetic energy conserving Computational Fluid Dynamics (CFD) code. CDP is a parallel unstructured grid incompressible flow solver, developed at the Center for Integrated Turbulence Simulations (CITS) at Stanford University. Two models of synthetic jet actuators have been developed and validated. The first is a detailed model in which the flow in and out of the actuator cavity is modeled. A second less costly model (RSSJ) was also developed in which the Reynolds stress produced by the actuator is modeled, based on information from the detailed model. Several static validation test cases at different angle of attack with modified NACA4415 and Dragon Eye airfoils were performed. Numerical results show the effects of the actuators on the vortical structure of the flow, as well as on the aerodynamic properties. The main effect of the actuation on the time averaged vorticity field is a bending of the separation shear layer from the actuator toward the airfoil surface, resulting in changes in the aerodynamic properties. Full actuation of the suction side actuator reduces the pitching moment and increases the lift force, while the pressure side actuator increases the pitching moment and reduces the lift force. These observations are in agreement with experimental results. The effectiveness of the actuator is measured by the change in the aerodynamic properties of the airfoil in particular the lift (Δ Cl) and moment (ΔCm) coefficients. Computational results for the actuator effectiveness show very good agreement with the experimental values (over the range of -2° to 10°). While the actuation modifies the global pressure distribution, the most pronounced effects are near the trailing edge in which a spike in the pressure coefficient (Cp) is observed. The local reduction of Cp, for both the suction side and pressure side actuators, at [special characters omitted] = 0.96 (the position of the actuators) is about 0.9 with respect to the unactuated case. This local reduction of the pressure is associated with the trapped vorticity and flow acceleration close to the trailing edge. The RSSJ model is designed to capture the synthetic jet time averaged behavior so that the high actuation frequencies are eliminated. This allows the time step to be increased by a factor of 5. This ad hoc model is also tested in dynamic simulations, in which its capacity to capture the detail model average performance was demonstrated. Finally, the RSSJ model was extended to a different airfoil profile (Dragon Eye) with good results.
546 $a English
590 $a School code: 0227
650 4 $a Mechanics. $3 525881
650 4 $a Aerospace engineering. $3 1002622
650 4 $a Mechanical engineering. $3 649730
653 $a Airfoils
653 $a Delayed detached eddy simulation
653 $a Flow control
653 $a Synthetic jets
690 $a 0346
690 $a 0538
690 $a 0548
710 2 $a The University of Texas at Austin. $b Mechanical Engineering. $e degree granting institution. $3 3815720
720 1 $a Moser, Robert D. $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 72-08B.
790 $a 0227
791 $a Ph.D.
792 $a 2009
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3439392