Investigating materials weathering at hypersonic velocities

Investigating materials weathering at hypersonic velocities
by Sophie Jenkins
London, UK (SPX) Jan 14, 2025

When objects travel through the atmosphere at hypervelocity, they face potential damage from dust particles and water droplets suspended in the air. To better understand these interactions, researchers have developed innovative experiments that simulate weather conditions by observing how hypersonic bodies interact with droplets.

The experiments focused on the role of droplet size and shape in determining the extent of damage caused during high-speed collisions. A Light Gas Gun facility was used to propel various materials at extremely high velocities, introducing water droplets into the system to simulate real-world atmospheric interactions. Advanced diagnostic tools provided detailed insights into these dynamic events.

A critical tool in these experiments was the Kirana ultra-high-speed video camera, capable of capturing up to 5 million frames per second. This technology allowed researchers to closely observe the behavior of projectiles traveling at 2.4 km/s as they interacted with water droplets in a low-pressure nitrogen environment. The study revealed complex phenomena, including droplet breakup, edge-stripping, and liquid jetting at the point of impact.

The Kirana camera offers unparalleled imaging capabilities, combining the flexibility of a video camera with the speed and resolution of high-performance framing cameras. Its custom-designed sensor can capture up to 7 million images per second at full resolution, providing 180 frames per event to document intricate interactions in exceptional detail.

This technology builds on foundational principles of high-speed aerodynamics and fluid dynamics. When an object moves at hypersonic speeds, air compression and heat generation can cause significant physical and thermal stresses on materials. The interaction between high-speed objects and liquid droplets introduces additional complexities, such as rapid phase changes and the formation of shock waves. Understanding these effects is critical for designing materials that can withstand the extreme conditions experienced during high-speed travel, such as those encountered by spacecraft re-entering Earth's atmosphere or by high-performance aircraft.

By employing advanced imaging technologies like the Kirana camera, researchers are able to observe and analyze these fast-moving interactions in unprecedented detail. This provides valuable data for improving material resilience and optimizing designs for extreme environments.

Research Report:High-Speed Imaging of Droplet Impact on a Hypervelocity Projectile.