DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

The Starting Process of a Pulsed Jet as seen by Schlieren Measurements

Wolf, Christian C. and Gardner, Anthony Donald and Ewers, Benjamin and Raffel, Markus (2014) The Starting Process of a Pulsed Jet as seen by Schlieren Measurements. AIAA Journal, 52 (8), pp. 1821-1826. American Institute of Aeronautics and Astronautics (AIAA). doi: 10.2514/1.J053198. ISSN 0001-1452.

Full text not available from this repository.

Official URL: http://arc.aiaa.org | DOI: 10.2514/1.J053198


Pulsed jets are amongst the most common measures of active flow control. For example applied to airfoils, stall effects can be dampened or even suppressed, and, hence, the aerodynamic performance can be improved. Although the implementation is more complex, pulsed jets often prove to be a superior alternative to their continuous counterparts. The current jets were designed with respect to the dynamic stall behavior of helicopter rotor blades. Dynamic stall is a well-known limit for forward flight speeds or maneuver loads that can be addressed using flow control. The current work investigates the starting process of a pulsed jet by means of the Background Oriented Schlieren Technique (BOS), using both ‘standard’ and ‘laser-speckle’ background patterns. In agreement with PIV measurements, the results reveal that the initial structure of the start-up process consists of a vortex ring with increasing diameter but constant convection velocity. The vortex is followed by a turbulent wake and a steady but unadapted supersonic jet with corresponding cell structure. The significance of the results is increased by a volumetric reconstruction of the density data, offering further details of the spatial structures. The experimental setup of BOS is not only more convenient in comparison to a standard PIV setup, but also reveals very different phenomena in a single exposure, without additional considerations regarding the follow-up behavior of tracer particles, double-frame time shift, etc.

Item URL in elib:https://elib.dlr.de/88412/
Document Type:Article
Additional Information:Published online: 12 May 2014
Title:The Starting Process of a Pulsed Jet as seen by Schlieren Measurements
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Wolf, Christian C.christian.wolf (at) dlr.deUNSPECIFIED
Gardner, Anthony Donaldtony.gardner (at) dlr.deUNSPECIFIED
Ewers, Benjaminbenjamin.ewers (at) dlr.deUNSPECIFIED
Raffel, Markusmarkus.raffel (at) dlr.deUNSPECIFIED
Journal or Publication Title:AIAA Journal
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.2514/1.J053198
Page Range:pp. 1821-1826
Publisher:American Institute of Aeronautics and Astronautics (AIAA)
Series Name:Technical Notes
Keywords:Background Oriented Schlieren Technique (BOS), flow control, volumetric reconstruction
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:rotorcraft
DLR - Research area:Aeronautics
DLR - Program:L RR - Rotorcraft Research
DLR - Research theme (Project):L - The Virtual Aerodynamic Rotorcraft (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Helicopters
Deposited By: Micknaus, Ilka
Deposited On:14 Jul 2014 15:37
Last Modified:08 Mar 2018 18:42

Repository Staff Only: item control page

Help & Contact
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.