An experimental campaign was carried out to investigate the characteristics of the transitional supersonic wake downstream of a single roughness element. Two Mach numbers were tested, 1.6 and 2.3, and… Click to show full abstract
An experimental campaign was carried out to investigate the characteristics of the transitional supersonic wake downstream of a single roughness element. Two Mach numbers were tested, 1.6 and 2.3, and two roughness heights, 0.1 mm and 1 mm. Unsteady and steady wall temperature measurements were taken along and across the roughness wake. The spatial trends of adiabatic wall temperature and heat flux, and the spectral time evolution of temperature were documented in this paper. The initial wall temperature was varied during the temperature measurements, and the resulting steady and unsteady effects on the roughness wake were investigated. The streamwise trends of heat-flux and adiabatic-wall temperature confirmed the transitional nature of the roughness wake. Spectral analysis showed that roughness height and initial wall temperature had the same type of effect on the wake wall-temperature fluctuations. The effect of roughness height was more sensible at Mach 2.3, ant that of the initial wall temperature was more evident with the smallest roughness also tested at Mach 2.3.
               
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