Pressure fluctuations beneath turbulent spots and instability wave packets in a hypersonic boundary layer.
Conference
·
OSTI ID:1038193
- Purdue University, West Lafayette, IN
The development of turbulent spots in a hypersonic boundary layer was studied on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Under quiet flow conditions, the nozzle wall boundary layer remains laminar and grows very thick over the long nozzle length. This allows the development of large turbulent spots that can be readily measured with pressure transducers. Measurements of naturally occurring wave packets and developing turbulent spots were made. The peak frequencies of these natural wave packets were in agreement with second-mode computations. For a controlled study, the breakdown of disturbances created by spark and glow perturbations were studied at similar freestream conditions. The spark perturbations were the most effective at creating large wave packets that broke down into turbulent spots. The flow disturbances created by the controlled perturbations were analyzed to obtain amplitude criteria for nonlinearity and breakdown as well as the convection velocities of the turbulent spots. Disturbances first grew into linear instability waves and then quickly became nonlinear. Throughout the nonlinear growth of the wave packets, large harmonics are visible in the power spectra. As breakdown begins, the peak amplitudes of the instability waves and harmonics decrease into the rising broad-band frequencies. Instability waves are still visible on either side of the growing turbulent spots during this breakdown process.
- Research Organization:
- Sandia National Laboratories
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1038193
- Report Number(s):
- SAND2010-8879C
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pressure fluctuations beneath instability wavepackets and turbulent spots in a hypersonic boundary layer
Fluid-Structure Interactions using Controlled Disturbances on a Slender Cone in Hypersonic Flow
Hypersonic Fluid-Structure Interactions on a Slender Cone
Journal Article
·
Mon Sep 08 20:00:00 EDT 2014
· Journal of Fluid Mechanics
·
OSTI ID:1111311
Fluid-Structure Interactions using Controlled Disturbances on a Slender Cone in Hypersonic Flow
Technical Report
·
Thu Sep 01 00:00:00 EDT 2016
·
OSTI ID:1562206
Hypersonic Fluid-Structure Interactions on a Slender Cone
Journal Article
·
Sat Jan 06 19:00:00 EST 2018
· AIAA Journal
·
OSTI ID:1477865