Unsteady pressure-sensitive paint measurement based on the heterodyne method using low frame rate camera

Area of Science:

• Fluid Dynamics
• Optical Measurement Techniques

Background:

• Accurate measurement of unsteady flow fields is crucial in fluid dynamics.
• Traditional pressure measurement methods can be limited in dynamic scenarios.

Purpose of the Study:

• To introduce a novel pressure-sensitive paint technique for precise pressure measurement in unsteady flow fields.
• To demonstrate the effectiveness of the heterodyne method for capturing pressure fluctuations.

Main Methods:

• Utilized a pressure-sensitive paint technique based on the heterodyne method.
• Detected beat signals from interference between a modulated light source and pressure fluctuations.
• Captured signals using a camera by adjusting light frequency and camera frame rate to isolate target frequencies and eliminate noise.

Main Results:

• Successfully measured pressure fluctuations in a resonance tube at fundamental, second, and third harmonics.
• Obtained pressure fluctuation distributions that were consistent with traditional pressure transducer measurements.
• Demonstrated the capability to detect specific frequencies of interest while filtering out noise.

Conclusions:

• The proposed heterodyne-based pressure-sensitive paint technique enables precise measurement of unsteady flow fields.
• This optical method offers a valuable and accurate approach for studying dynamic pressure phenomena.
• The technique shows significant potential for advancing research in fluid dynamics and related fields.