Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


ucin1123778509.pdf (13.55 MB)

ETD Abstract Container

Abstract Header

A NUMERICAL STUDY OF THE EFFECT OF FREQUENCY OF PULSED FLOW CONTROL APPLIED TO A RECTANGULAR CAVITY IN SUPERSONIC CROSSFLOW

STANEK, MICHAEL JOSEPH
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123778509

Abstract Details

2005, PhD, University of Cincinnati, Engineering : Aerospace Engineering.
Stabilization of turbulent free shear flows is a poorly understood, and recently discovered flow phenomenon,not described in modern textbooks on fluid dynamics. This dissertation describes the design and large-scale experimental test of one type of flow control actuator, a rod in crossflow, which is shown to pulse at high frequency (relative to the dominant instabilities of a turbulent free shear layer), and in the process, locally stabilizes that shear layer. The shear layer in question spans a cavity (representative of a 1/10th scale modern aircraft weapons bay) in supersonic (Mach 1.2)crossflow. Without the high frequency flow control, the cavity experiences acoustic resonance (and the creation of large coherent vortical structures), which creates sound pressure levels high enough to fatigue aircraft components. With the high frequency control (and the local shear layer stabilization), the sound pressure levels are rendered benign. Evidence of suppression due to other types of high frequency pulsing devices (primarily resonance tube type designs) is also presented. A numerical study is undertaken to investigate the nature of the stabilization and acoustic suppression. An implicit, 2nd-order in space and time flow solver, coupled with a recently-developed hybrid RANS - LES turbulence model by Nichols,is utilized in a Chimera-based parallel format, to numerically simulate both the unsuppressed cavity in resonance, as well as the effect of pulsing flow control. Due to the limited ability to vary frequency using a rod in crossflow type device, a pulsed jet device is simulated instead. Frequency (and in a limited number of cases, amplitude) of pulse is varied, from 0 Hz (steady) up to 5000 Hz. The change in the character of the flow control effect as pulsing frequency is changed is described, and linked to changes in acoustic levels. The observed local stabilization of the cavity turbulent shear layer is shown in simulation to be the result of a violent instability and breakdown of the injected vortical structure caused by the high frequency pulsing. This behavior is only observed in simulation above a certain critical frequency. Below this critical frequency, pulsing is shown in simulation to provide little benefit with respect to suppression of high cavity acoustic levels.
Dr. Stanley Rubin (Advisor)
270 p.
Engineering, Aerospace
Fluid Dynamics; Flow Control; High Frequency; Cavity; Weapons Bay

Recommended Citations

Citations

  • STANEK, M. J. (2005). A NUMERICAL STUDY OF THE EFFECT OF FREQUENCY OF PULSED FLOW CONTROL APPLIED TO A RECTANGULAR CAVITY IN SUPERSONIC CROSSFLOW [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123778509

    APA Style (7th edition)

  • STANEK, MICHAEL. A NUMERICAL STUDY OF THE EFFECT OF FREQUENCY OF PULSED FLOW CONTROL APPLIED TO A RECTANGULAR CAVITY IN SUPERSONIC CROSSFLOW. 2005. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123778509.

    MLA Style (8th edition)

  • STANEK, MICHAEL. "A NUMERICAL STUDY OF THE EFFECT OF FREQUENCY OF PULSED FLOW CONTROL APPLIED TO A RECTANGULAR CAVITY IN SUPERSONIC CROSSFLOW." Doctoral dissertation, University of Cincinnati, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123778509

    Chicago Manual of Style (17th edition)

ucin1123778509
1,169
© 2005, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.