Multi-frame multi-exposure shock wave imaging and pressure measurements

Area of Science:

• Physics
• Optical Engineering
• Fluid Dynamics

Background:

• Traditional shock wave detection methods like streak cameras have limitations in resolution and measurement distance.
• Accurate measurement of shock wave pressure and velocity is crucial for understanding various physical phenomena.

Purpose of the Study:

• To develop and demonstrate a novel all-optical measurement setup for high-resolution shock wave velocity and pressure detection.
• To overcome the limitations of traditional methods in measuring shock waves closer to their origin.

Main Methods:

• A custom-built illumination system capable of multi-frame, multi-exposure imaging at multi-MHz frame rates and high illumination pulse repetition frequencies (up to 200 MHz).
• Integration with a fiber-optic probe hydrophone for independent verification of shock wave pressure and time-of-flight measurements.
• Development of a technique for measuring shock wave velocity in all in-plane directions.

Main Results:

• Achieved high-speed, multi-directional shock wave velocity measurements.
• Measured shock wave pressures exceeding 500 MPa at approximately 100 µm from the plasma center.
• Indicated pressures above 1 GPa at even shorter distances using camera-based measurements, validated by hydrophone data.

Conclusions:

• The novel all-optical setup provides accurate, high-resolution measurements of shock wave parameters closer to the source than previously possible.
• This technique offers a significant advancement for studying high-pressure, dynamic events in fluids.
• The combined optical and hydrophone approach offers robust verification for shock wave characterization.