Infrared thermography of transition due to isolated roughness elements in hypersonic flows
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2016-02-01 |
| Journal | Physics of Fluids |
| Authors | Francesco Avallone, Ferry Schrijer, Gennaro Cardone |
| Institutions | University of Naples Federico II, Delft University of Technology |
| Citations | 20 |
Abstract
Section titled āAbstractāBoundary layer transition in high-speed flows is a phenomenon that despite extensive research over the years is still extremely hard to predict. The presence of protrusions or gaps can lead to an accelerated laminar-to-turbulent transition enhancing the thermal loads and the skin friction coefficient. In the current investigation, inverse heat transfer measurements using infrared thermography are performed on the flow past different roughness geometries in the form of cylinders and diamond at free stream Mach number equal to 7.5, h/Ī“ ranging between 0.5 and 0.9 (where h is the roughness height and Ī“ is the boundary layer thickness), and ReĪø ranging between 1305 and 2450. The roughness elements are positioned on a 5Ā° ramp placed at zero angle of attack. The measurements indicate that the roughness geometry influences the transitional pattern while the frontal area influences both the transition location and the maximum value of the Stanton number along the centreline. Moreover, there is a strong connection between the streamwise centreline Stanton number and the spreading of the wake width. In particular, the transition process is characterized by an approximately constant wake width. Differently, the wake width spreads at the location where the streamwise centreline Stanton number reaches the turbulent level. This point corresponds to a local maximum of the wake amplitude defined as one half of the maximum spanwise variation of the Stanton number.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal SourceāReferences
Section titled āReferencesā- 2008 - Effects of roughness on hypersonic boundary-layer transition [Crossref]
- 2002 - Review and synthesis of roughness-dominated transition correlations for reentry applications [Crossref]
- 1998 - Shuttle orbiter experimental boundary-layer transition results with isolated roughness [Crossref]
- 1962 - Effects of slight nose bluntness and roughness on boundary layer transition in supersonic flows [Crossref]
- 1967 - Boundary layer transition on blunt bodies-effects of roughness [Crossref]
- 2008 - Effect of freestream noise on roughness-induced transition for the X-51A forebody [Crossref]
- 2011 - Effect of freestream noise on roughness-induced transition for a slender cone [Crossref]