Hypersonic Boundary Layer Stability Experiments On A Flared Cone Model At Angle Of Attack In A Quiet Wind Tunnel
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Author | : National Aeronautics and Space Adm Nasa |
Publisher | : |
Total Pages | : 134 |
Release | : 2018-11-18 |
Genre | : |
ISBN | : 9781731266217 |
Download Hypersonic Boundary-Layer Stability Experiments on a Flared-Cone Model at Angle of Attack in a Quiet Wind Tunnel Book in PDF, Epub and Kindle
An experimental investigation of the effects of angle of attack on hypersonic boundary-layer stability on a flared-cone model was conducted in the low-disturbance Mach-6 Nozzle-Test Chamber Facility at NASA Langley Research Center. This unique facility provided a 'quiet' flow test environment which is well suited for stability experiments because the low levels of freestream 'noise' minimize artificial stimulation of flow-disturbance growth. Surface pressure and temperature measurements documented the adverse-pressure gradient and transition-onset location. Hot-wire anemometry diagnostics were applied to identify the instability mechanisms which lead to transition. In addition, the mean flow over the flared-cone geometry was modeled by laminar Navier-Stokes computations. Results show that the boundary layer becomes more stable on the windward ray and less stable on the leeward ray relative to the zero-degree angle-of-attack case. The second-mode instability dominates the transition process at a zero-degree angle of attack, however, on the windward ray at an angle of attack this mode was completely stabilized. The less-dominant first-mode instability was slightly destabilized on the windward ray. Non-linear mechanisms such as saturation and harmonic generation are identified from the flow-disturbance bispectra. Doggett, Glen P. and Chokani, Ndaona Langley Research Center ANGLE OF ATTACK; AERODYNAMIC NOISE; ZERO ANGLE OF ATTACK; BOUNDARY LAYER STABILITY; HYPERSONIC SPEED; NAVIER-STOKES EQUATION; HYPERSONICS; AERODYNAMIC STABILITY; HYPERSONIC BOUNDARY LAYER; WIND TUNNELS; VELOCITY MEASUREMENT; TEST CHAMBERS; LOW NOISE...
Author | : Glen P. Doggett |
Publisher | : |
Total Pages | : 136 |
Release | : 1996 |
Genre | : |
ISBN | : |
Download Hypersonic Boundary-Layer Stability Experiments on a Flared-Cone Model at Angle of Attack in a Quiet Wind Tunnel Book in PDF, Epub and Kindle
Author | : National Aeronautics and Space Administration (NASA) |
Publisher | : Createspace Independent Publishing Platform |
Total Pages | : 232 |
Release | : 2018-07-25 |
Genre | : |
ISBN | : 9781724242556 |
Download Hypersonic Boundary Layer Stability Experiments in a Quiet Wind Tunnel with Bluntness Effects Book in PDF, Epub and Kindle
Hypersonic boundary layer measurements over a flared cone were conducted in a Mach 6 quiet wind tunnel at a freestream unit Reynolds number of 2.82 million/ft. This Reynolds number provided laminar-to-transitional flow over the cone model in a low-disturbance environment. Four interchangeable nose-tips, including a sharp-tip, were tested. Point measurements with a single hot-wire using a novel constant voltage anemometer were used to measure the boundary layer disturbances. Surface temperature and schlieren measurements were also conducted to characterize the transitional state of the boundary layer and to identify instability modes. Results suggest that second mode disturbances were the most unstable and scaled with the boundary layer thickness. The second mode integrated growth rates compared well with linear stability theory in the linear stability regime. The second mode is responsible for transition onset despite the existence of a second mode subharmonic. The subharmonic disturbance wavelength also scales with the boundary layer thickness. Furthermore, the existence of higher harmonics of the fundamental suggests that nonlinear disturbances are not associated with 'high' free stream disturbance levels. Nose-tip radii greater than 2.7% of the base radius completely stabilized the second mode. Lachowicz, Jason T. and Chokani, Ndaona Langley Research Center NASA-CR-198272, NAS 1.26:198272 NCC1-183; RTOP-505-59-50-02...
Author | : Jason Thomas Lachowicz |
Publisher | : |
Total Pages | : 232 |
Release | : 1996 |
Genre | : |
ISBN | : |
Download Hypersonic Boundary Layer Stability Experiments in a Quiet Wind Tunnel with Bluntness Effects Book in PDF, Epub and Kindle
Author | : Alan E. Blanchard |
Publisher | : |
Total Pages | : 120 |
Release | : 1996 |
Genre | : Aerodynamics, Hypersonic |
ISBN | : |
Download An Experimental Investigation of Wall-Cooling Effects on Hypersonic Boundary-Layer Stability in a Quiet Wind Tunnel Book in PDF, Epub and Kindle
One of the primary reasons for developing quiet tunnels is for the investigation of high-speed boundary-layer stability and transition phenomena without the transition-promoting effects of acoustic radiation from tunnel walls. In this experiment, a flared-cone model under adiabatic- and cooled-wall conditions was placed in a calibrated, "quiet" Mach 6 flow and the stability of the boundary layer was investigated using a prototype constant-voltage anemometer. The results of this experiment were compared with linear-stability theory predictions and good agreement was found in the prediction of second-mode frequencies and growth. In addition, the same "N = 10" criterion used to predict boundary-layer transition in subsonic, transonic, and supersonic flows was found to be applicable for the hypersonic flow regime as well. Under cooled-wall conditions, a unique set of continuous spectra data was acquired that documents the linear, nonlinear, and breakdown regions associated with the transition of hypersonic flow under low-noise conditions
Author | : Jason T. Lachowicz |
Publisher | : |
Total Pages | : |
Release | : 1996 |
Genre | : |
ISBN | : |
Download Hypersonic Boundary Layer Stability Over a Flared Cone in a Quiet Tunnel Book in PDF, Epub and Kindle
Author | : Kenneth F. Stetson |
Publisher | : |
Total Pages | : 116 |
Release | : 1990 |
Genre | : Aerodynamics, Hypersonic |
ISBN | : |
Download Comments on Hypersonic Boundary-layer Transition Book in PDF, Epub and Kindle
This is a survey paper on the subject of hypersonic boundary-layer transition. Part 1 discusses boundary-layer stability theory, hypersonic boundary-layer stability experiments, and a comparison between theory and experiment. Part 2 contains comments on how many configuration and flow parameters influence transition. Part 3 discusses some additional general aspects of transition. Part 4 discusses problems of predicting transition and comments on three prediction methods. Part 5 contains some general guidelines for prediction methodology. Keywords: Boundary layer transition, Boundary layer stability, Hypersonic boundary layers.
Author | : Glen Patrick Doggett |
Publisher | : |
Total Pages | : 300 |
Release | : 1996 |
Genre | : |
ISBN | : |
Download Hypersonic Boundary-layer Stability on a Flared-cone Model at Angle of Attack Book in PDF, Epub and Kindle
Author | : National Aeronautics and Space Administration NASA |
Publisher | : |
Total Pages | : 30 |
Release | : 2018-10-23 |
Genre | : |
ISBN | : 9781729140024 |
Download A Quiet Tunnel Investigation of Hypersonic Boundary-Layer Stability Over a Cooled, Flared Cone Book in PDF, Epub and Kindle
A flared-cone model under adiabatic and cooled-wall conditions was placed in a calibrated, low-disturbance Mach 6 flow and the stability of the boundary layer was investigated using a prototype constant-voltage anemometer. The results were compared with linear-stability theory predictions and good agreement was found in the prediction of second-mode frequencies and growth. In addition, the same 'N = 10' criterion used to predict boundary-layer transition in subsonic, transonic, and supersonic flows under low freestream noise conditions was found to be applicable for the hypersonic flow regime as well. Under cooled-wall conditions, a unique set of spectral data was acquired that documents the linear, nonlinear, and breakdown regions associated with the transition of hypersonic flow under low-noise conditions. Blanchard, Alan E. and Selby, Gregory V. and Wilkinson, Stephen P. Langley Research Center NCC1-180...
Author | : |
Publisher | : |
Total Pages | : 686 |
Release | : 1997 |
Genre | : Fluid dynamics |
ISBN | : |
Download 28th AIAA Fluid Dynamics Conference, 4th AIAA Shear Flow Control Conference Book in PDF, Epub and Kindle