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We experimentally evaluated the impulsive motion of free-surface of water on impingement of shock-waves of moderate strength. This physical process creates the initial acceleration in shock-wave based micro-fluidic devices, which have promising medical and drug/DNA delivery applications. The velocities of the water interfaces were measured through real-time high-temporal/spatial resolution visualizations. Based on modified Tait equation-of-state and the concept of Reimann-invariants, an analytical expression was deduced to calculate the particle velocity behind the unloading wave. The experiments and analyses confirm that the mass motion behind the shock-wave accelerates to very high velocities, a requirement for effective momentum delivery in micro-jet devices.

Safe and efficient hypersonic missions require exhaustive testing to capture the surface heat flux used in optimizing thermal protection systems. Though low, base heat transfer rates are still relevant and their estimation is of the utmost importance. Impulse hypersonic test facilities like the shock tunnel are commonly used for such estimation tests. The present paper compares contemporary heat flux measurement techniques, namely, E‐type coaxial thermocouples, Pt‐thin films, and atomic layer thermopiles in a hypersonic shock tunnel at the base of a scaled‐down re‐entry capsule. Base flow establishment is ensured using pressure measurements. The measurements indicated that the base‐stagnation point heat flux was approximately 2% to 3% of the forebody stagnation heat flux and it stabilized at an approximate nondimensional establishment time of 43.2 ± 2.4.

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