Effect of microramps on flare-induced shock – boundary-layer interaction

2019 ◽  
Vol 124 (1271) ◽  
pp. 121-149 ◽  
Author(s):  
T. Nilavarasan ◽  
G. N. Joshi ◽  
A. Misra
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Thickness ◽  
Separation Bubble ◽  
Layer Interaction ◽  
Compression Corner ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction ◽  
Control Shock ◽  
Bubble Structure ◽  
Flare Model

AbstractThe ability of microramps to control shock - boundary layer interaction at the vicinity of an axisymmetric compression corner was investigated computationally in a Mach 4 flow. A cylinder/flare model with a flare angle of 25° was chosen for this study. Height (h) of the microramp device was 22% of the undisturbed boundary layer thickness (δ) obtained at the compression corner location. A single array of these microramps with an inter-device spacing of 7.5h was placed at three different streamwise locations viz. 5δ, 10δ and 15δ (22.7h, 45.41h and 68.12h in terms of the device height) upstream of the corner and the variations in the flowfield characteristics were observed. These devices modified the separation bubble structure noticeably by producing alternate upwash and downwash regions in the boundary layer. Variations in the separation bubble’s length and height were observed along the spanwise (circumferential) direction due to these devices.

scholarly journals Effect of wall temperature on separation bubble size in laminar hypersonic shock/boundary layer interaction flows

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988555 ◽  
Author(s):  
Amjad A Pasha ◽  
Khalid A Juhany
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Mach Number ◽  
Wall Temperature ◽  
Separation Bubble ◽  
Layer Interaction ◽  
Shock Boundary Layer Interaction ◽  
Boundary Layer Interaction ◽  
Hypersonic Shock ◽  
Bubble Length

At hypersonic speeds, the external wall temperatures of an aerospace vehicle vary significantly. As a result, there is a considerable heat transfer variation between the boundary layer and the wall of the hypersonic vehicle. In this article, numerical computations are performed to investigate the effect of wall temperature on the separation bubble length in laminar hypersonic shock-wave/boundary-layer interaction flows over double-cone configuration at the Mach number of 12.2. The flow field is described in detail in terms of different shocks, expansion fans, shear layer and separation bubble. The variation of the Prandtl number has a negligible effect on the flow field and wall data. A specific heat ratio of less than 1.4 results in the better prediction of wall pressure and heat flux in the shock/boundary-layer interaction region. It is observed that as the wall temperature is increased, the separation bubble size and hence the separation shock length increases. The high firmness of the laminar boundary-layer at a high Mach number shows that the wall temperature in the shock/boundary-layer interaction region has little effect. The peak wall pressure and heat flux decrease with an increase in wall temperature. An estimation is developed between separation bubble length and wall temperature based on the computed results.

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