Structure and Modes of Supersonic Base Flow
Abstract
This proposal seeks to perform an experimental investigation of the structure and modes of supersonic base flow. Specifically, detailed stereo and tomographic particle image velocimetry (PIV) measurements will be made of the near-wake flow. Detailed analyses of the experimental results will be performed to elucidate characteristic structures within the wake. These measurements and analyses will provide advanced understanding of these massively separated, unsteady, turbulent, compressible flows and improve prediction and control capabilities. The experimental approach will utilize state-of-the-art particle image velocimetry techniques, including tomographic PIV, which is a volumetric technique enabling three-dimensional velocity measurements to be obtained over a reasonably sized volumetric spatial field. A specialized particle seeder is implemented in order to overcome the significant challenges associated with seeding a flow of this type. The flow to be investigated is a Mach 2.5 flow around an axisymmetric cylindrical blunt-base model. Detailed quantitative measurement and visualization of the recirculation region, shear layer, and initial part of the trailing wake will be investigated. Instantaneous quantitative velocity measurements will allow the structure of the near-wake flow to be analyzed using a variety of techniques, including proper orthogonal decomposition, empirical mode decomposition, the Q-criterion, and the swirling strength criterion. Statistical data including mean velocities and the full Reynolds stress tensor will provide the capability to both understand the basic nature of the flow, as well as to provide a spatially resolved baseline for comparison with other studies, particularly computational efforts. In addition, questions may be answered regarding the presence (or absence) of helical structures as suggested by numerical investigations, the relationship between the instantaneous base pressure distribution and the instantaneous recirculation region structures, and whether such structures give indications of novel control strategies that might be employed. The tomographic PIV system was provided by 65057-EG-RIP and has been procured, installed, and is in use.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 13, 2016
- Source ID
- W911NF1510194
Entities
People
- Craig Dutton
Organizations
- Army Contracting Command
- United States Army
- University of Illinois Urbana–Champaign