A parametric study of laminar and transitional oblique shock wave reflections

Abstract

High-resolution particle image velocimetry measurements were performed on laminar and transitional oblique shock wave reflections for a range of Mach numbers ($M=1.6{-}2.3$), Reynolds numbers ($Re_{x_{sh}}=1.4\times 10^{6}{-}3.5\times 10^{6}$) and flow deflection angles ($\unicode[STIX]{x1D703}=1^{\circ }{-}5^{\circ }$ or $p_{3}/p_{1}=1.11{-}1.64$). The laminar interactions revealed a long, flat and triangular shaped separation bubble. For relatively strong interactions ($p_{3}/p_{1}>1.2$), the bubble grows linearly in the upstream direction with increasing shock strength. Under these conditions, the boundary layer keeps an on average laminar velocity profile up to the shock impingement location, followed by a quick transition and subsequent reattachment of the boundary layer. For weaker interactions ($p_{3}/p_{1}<1.2$), the boundary layer is able to remain laminar further downstream of the bubble, which consequently results in a later reattachment of the boundary layer. The pressure distribution at the interaction onset for all laminar cases shows excellent agreement with the free-interaction theory, therefore supporting its validity even for incipiently separated laminar oblique shock wave reflections.

Theoretical study on regular reflection of shock wave–boundary layer interactions

“…In addition, when β MEP is much weaker than β FIT0 , the separation bubble should be much smaller, reducing the height of the interaction point, which might be inside of the boundary layer, as shown in figure 9(c). This configuration corresponds to relatively weak incident shock waves, and it can explain the work conducted on small angle wedges by Giepman et al (2018), who found the pressure plateau could not reach the FIT pressure rise.…”

The effect of flow confinement on laminar shock-wave/boundary-layer interactions

“…While many real-world applications will be fully turbulent, laminar solutions provide useful comparisons to wind tunnel experiments where smallscale models are investigated at lower Reynolds numbers. Examples of laminar and tripped-transitional experiments in supersonic SBLI include Hakkinen et al (1959), Degrez et al (1987), Giepman et al (2015Giepman et al ( , 2016Giepman et al ( , 2018, and Diop et al (2019), in which the interactions are not fully turbulent. Furthermore, shock and expansion wave patterns are easier to distinguish in the absence of turbulence and the mechanism of transition can be investigated in laminar SBLI.…”

“…Recent experimental studies on laminar-transitional SBLI include those of Giepman et al (2015) and Giepman et al (2018), in which a range of shock impingement locations were investigated for Mach numbers between M = [1.6, 2.3]. All experiments were performed with high-resolution PIV in a wind tunnel with a partial-span shock generator.…”

Shock-Wave/Boundary-Layer Interactions in Transitional Rectangular Duct Flows

“…While turbulent duct SBLI has received some attention in recent years, laminar and transitional interactions in ducts are not as well understood. The work of Giepman et al (2018) also noted experimental difficulties when seeding boundary layers in a laminar case. Numerical simulations are well placed to investigate SBLI for transitional interactions and complement existing experimental literature.…”