The Role of Corner Curvature in the Origin of Heat Streaks on Swept Geometries in Hypersonic Flows
Currin, J., Smotzer, J., Siddiqui, F., Garza, S. Van Poppel, B., and Leyva, I.
To investigate the formation and behavior of streamwise heat streaks in hypersonic flow, a simplified highly-swept model with a second-order continuous leading edge was tested in the Actively Controlled Expansion (ACE) hypersonic tunnel at Texas A&M University. The study aimed to examine the effects of shock curvature and the influence of second-order leading edge continuity on heat streak behavior at Mach 5.7 across a variety of pitch angles and Reynolds numbers. Diagnostic techniques for analysis included high-speed schlieren, infrared thermography, and surface-mounted pressure transducers. The results showed that heat streaks developed along the test article’s surface, with their intensity increasing with both Reynolds number and angle of attack. The streaks were less intense and appeared further downstream compared to those observed on geometries with second-order discontinuous leading edges under identical conditions. In addition, their spanwise location shifted inward with increasing angle of attack. Surface pressure spectra revealed broadband disturbances from 15 to 50 kHz at various positions along the model, with characteristic frequencies remaining constant but intensities scaling with flow conditions. These findings suggest that, while second-order continuity of the leading edge may reduce initial shock curvature concentrations, it does not solely eliminate the generation of vortical structures responsible for localized heating in laminar hypersonic flows. Spanwise pressure gradients and the turning radius of the corner, regardless of the continuity of the leading edge, play a key role in the formation of heat streaks.
Variable Nose Model Design with Dimensions
Spanwise Slice of Heat Flux at x/L = 0.687, M = 5.7, Angle of Attack = 0 degrees.
Experimental and Computational Investigation on the Origin of Heat Streaks for Swept Geometries in Hypersonic Flows
Lakin, G., Smotzer, J., Morrealle, B., Van Poppel, B., and Leyva, I.
A simplified, swept-wedge model was tested in the Actively Controlled Expansion (ACE) Hypersonic Tunnel at Texas A\&M University over a range of freestream conditions to isolate the origin of heat streaks emanating from a junction between the leading edge and the swept-sides of the model. High-speed schlieren imagery, infrared thermography, and surface-mounted transducers were used to characterize the heat streaks at several angles of attack and Reynolds numbers. A complementary computational study informed the placement of instrumentation relative to predicted streamwise streak locations. Schlieren imagery detailed the shape and structure of the bow shock and boundary layer, while infrared thermography showed two prominent heat streaks emanating from the junction between the leading edge and swept-sides of the model. Streak intensity was proportional to increases in angle of attack and Reynolds number. Power spectra for the surface pressure sensors observed broadband frequency responses in the range of 10-50 kHz under the streak and inboard toward the centerline. Spectra for each transducer showed that characteristic frequencies were invariant with angle of attack, while their intensity was proportionally related.
Swept wedge geometries used to study the effects of curvature on heat streaks: (a) discontinuous swept wedge with sharp transition to swept sides; (b) second-order continuous swept wedge with blended transition to swept sides; (c) comparison of leading edge profiles.
Swept wedge geometries used to study the effects of curvature on heat streaks: (a) discontinuous swept wedge with sharp transition to swept sides; (b) second-order continuous swept wedge with blended transition to swept sides; (c) comparison of leading edge profiles.
Heat Flux Slices at x/L=0.687, Re’=4.2M (left) and 7M (right) for Mach = 5.7, C2 Continuous Geometry
Heat Flux Slices at x/L=0.687, Re’=4.2M (left) and 7M (right) for Mach = 5.7, C2 Continuous Geometry
Heat Flux Slices at x/L=0.687, Re’=4.2M (left) and 7M (right) for Mach = 5.7, C2 Discontinuous Geometry
Heat Flux Slices at x/L=0.687, Re’=4.2M (left) and 7M (right) for Mach = 5.7, C2 Discontinuous Geometry