Shock Wave/Boundary Layer Interactions

Unsteady flow organization of compressible planar base flows

“…It would therefore appear that the relatively large ͗uЈ͘ production does not necessarily balance the tendency toward isotropy, an observation that has been attributed to the insufficient streamwise extent of the interaction process. 46 Maximum levels of the kinematic Reynolds shear stress throughout the near wake region are shown in Fig. 10.…”

Reattachment heating upstream of short compression ramps in hypersonic flow

“…As interpreted in Fig. 16a, the consequent increase in separation length with θ results in a longer distance (or mixing length) required by the separated shear layer to accelerate under the action of viscous forces and eventually attain sufficient momentum to overcome the obstacle (Délery and Marvin 1986). In this manner, peak heating rates are shown to vary accordingly as a function of the higher mass flow deflection and subsequent increase in separation length, with q ′ max increasing exponentially with ramp angle (Fig.…”

“…While the flow organisation may vary significantly across different (Sedney 1973;Sedney and Kitchens 1977;Ozcan and Holt 1984), results suggest that the organisation is dominated by the main horseshoe vortex and the localised counter-rotating vortex at the corner for the present range of interactions (0.17 × 10 5 < Re δ u < 0.47 × 10 5 ). The proximity of the present conditions to the Re δ u ≈ 1 × 10 5 threshold-which is often regarded as an approximate limit for Reynolds number trend reversal in separation length correlations (Délery and Marvin 1986)-places the present interactions within a relatively complex regime whereby both viscous and inviscid forces play a significant role.…”

“…5 and 6 would suggest that the interaction length scales approximately as L/δ ∝ Re 0.2 x M −1 o θ, for weak interactions with viscous and inertia forces of a similar magnitude (note free-interaction assumptions prime viscous effects). For strong interactions, whereby the inviscid terms are significantly greater than the viscous terms, the relevance of the hypersonic similarity parameter increases accordingly (Stollery 1970) so that, as further mentioned in Délery and Marvin (1986) and Arnal and Délery (2004), the extent of the separation scales as:…”

“…10b, the impingement of the separated shear layer upon primary reattachment on the front face of the obstacle (R 1 ) results in a stagnation region similar to that in hypersonic nose regions, consequently giving rise to very high heat transfer rates. While this appears more obvious for the θ = 90 • obstacle, a similarly localised stagnation of the flow is also expected to some extent upon reattachment of the shear layer in compression corner and incident shock interactions with separation (Délery and Marvin 1986), yet with the reattachment being inherently coupled to the highly complex viscous effects. Originally prompted by a need to better understand the nature of the heat transfer augmentation on the surface surrounding short protuberances-i.e.…”