A High Order Cut-Cell Method for Numerical Simulation of Hypersonic-Boundary Transition with Surface Roughness

Le, Duan

doi:10.2514/6.2008-3732

Cited by 5 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With the evolution of the vortices in the flow field, more complex new vortex structures are produced [5], and turbulent spots have arisen in regions possessing some turbulent characteristics [6], and eventually evolve into a fully developed turbulent flow [7]. Many transitional issues go deeply into the research [8][9][10][11]. In this paper, the direct numerical simulation (DNS) method is used to reveal the spatial transitional process of a flat-plate boundary layer.…”

mentioning

confidence: 99%

Evolution of the vortex structures and turbulent spots at the late-stage of transitional boundary layers

Chen

Tang

Lü

et al. 2011

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

The nonlinear evolution process of new vortex structures at the late-stage of the transition, including the 3-D spatial structure of barrel-shaped vortex and "dark spots" structure observed by experiment research, has been confirmed by our computational results. The formation mechanisms of these structures have been explored. It is revealed that the new vortex structures, the ring-like vortex chain and induced disturbance velocities play a dominant role in the generation of turbulent spots. boundary layers, transition, barrel-shaped vortex, turbulent spots, direct numerical simulation PACS: 47.27.Cn, 47.27

show abstract

mentioning

confidence: 99%

Evolution of the vortex structures and turbulent spots at the late-stage of transitional boundary layers

Chen

Tang

Lü

et al. 2011

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

show abstract

“…While simple roughness shapes can be handled with existing structured mesh computational tools, more complex roughness shapes of practical importance may cause difficulties in grid generation. For this reason, some researchers have used the immersed boundary formulation in conjunction with existing time-accurate compressible Navier-Stokes solvers to handle the roughness geometry [8,9]. While such an approach may be implemented in existing structured mesh codes, it could encounter difficulties in dealing with complicated shock patterns arising from the interaction of complex roughness geometries with the boundary layer flow.…”

Section: Introductionmentioning

confidence: 99%

Hypersonic viscous flow over large roughness elements

Chang

Choudhari

2010

Theor. Comput. Fluid Dyn.

View full text Add to dashboard Cite

Viscous flow over discrete or distributed surface roughness has great implications for hypersonic flight due to aerothermodynamic considerations related to laminar-turbulent transition. Current prediction capability is greatly hampered by the limited knowledge base for such flows. To help fill that gap, numerical computations are used to investigate the intricate flow physics involved.An unstructured mesh, compressible Navier-Stokes code based on the space-time conservation element, solution element (CESE) method is used to perform time-accurate Navier-Stokes calculations for two roughness shapes investigated in wind tunnel experiments at NASA Langley Research Center. It was found through 2D parametric study that at subcritical Reynolds numbers of the boundary layers, absolute instability resulting in vortex shedding downstream, is likely to weaken at supersonic free-stream conditions. On the other hand, convective instability may be the dominant mechanism for supersonic boundary layers. Three-dimensional calculations for a rectangular or cylindrical roughness element at post-shock Mach numbers of 4.1 and 6.5 also confirm that no self-sustained vortex generation is present.

show abstract

“…[1][2][3][4][5] It is well-known that the presence of protuberances or cavities in hypersonic boundary layers can lead to premature laminar turbulent transition in the wake region. Early transition to turbulence causes a rapid rise in surface heating, which in turn may impact the aerodynamic and aerothermodynamic performance of the vehicle.…”

Section: Introductionmentioning

confidence: 99%

Effects of Cavities and Protuberances on Transition over Hypersonic Vehicles

Chang

Choudhari

et al. 2011

41st AIAA Fluid Dynamics Conference and Exhibit

View full text Add to dashboard Cite

Surface protuberances and cavities on a hypersonic vehicle are known to cause several aerodynamic or aerothermodynamic issues. Most important of all, premature transition due to these surface irregularities can lead to a significant rise in surface heating. To help understand laminar-turbulent transition induced by protuberances or cavities on a Crew Exploration Vehicle (CEV) surface, high-fidelity numerical simulations are carried out for both types of trips on a CEV wind tunnel model. Due to the large bluntness, these surface irregularities reside in an accelerating subsonic boundary layer. For the Mach 6 wind tunnel conditions with a roughness Reynolds number Re kk of 800, it was found that a protuberance with a height to boundary layer thickness ratio of 0.73 leads to strong wake instability and spontaneous vortex shedding, while a cavity with identical geometry only causes a rather weak flow unsteadiness. The same cavity with a larger Reynolds number also leads to similar spontaneous vortex shedding and wake instability. The wake development and the formation of hairpin vortices for both protuberance and cavity were found to be qualitatively similar to that observed for an isolated hemisphere submerged in a subsonic, low speed flat-plate boundary layer. However, the shed vortices and their accompanying instability waves were found to be slightly stabilized downstream by the accelerating boundary layer along the CEV surface. Despite this stabilizing influence, it was found that the wake instability spreads substantially in both wall-normal and azimuthal directions as the flow is evolving towards a transitional state. Similarities and differences between the wake instability behind a protuberance and a cavity are investigated. Computations for the Mach 6 boundary layer over a slender cylindrical roughness element with a height to the boundary layer thickness of about 1.1 also shows spontaneous vortex shedding and strong wake instability. Comparisons of detailed flow structures associated with protuberances at subsonic and supersonic edge Mach numbers indicate distinctively different instability mechanisms. Nomenclature

show abstract

A High Order Cut-Cell Method for Numerical Simulation of Hypersonic-Boundary Transition with Surface Roughness

Cited by 5 publications

References 19 publications

Evolution of the vortex structures and turbulent spots at the late-stage of transitional boundary layers

Evolution of the vortex structures and turbulent spots at the late-stage of transitional boundary layers

Hypersonic viscous flow over large roughness elements

Effects of Cavities and Protuberances on Transition over Hypersonic Vehicles

Contact Info

Product

Resources

About