Characterization of Supersonic Compressible Fluid Flow Using High-Speed Interferometry.

Area of Science:

• Fluid Dynamics
• Optical Measurement Techniques
• Aerodynamics

Background:

• Accurate measurement of compressible fluid flow is crucial for aerodynamic research.
• Existing techniques can be intrusive or lack real-time quantitative data.
• Investigating phenomena like flutter in blade cascades requires precise flow field analysis.

Purpose of the Study:

• To develop and validate a highly sensitive, accurate, and portable interferometric technique for compressible fluid flow sensing.
• To enable nonintrusive investigation of aerodynamic phenomena.
• To provide a system for almost real-time quantitative data processing.

Main Methods:

• Development of a compact interferometer using a high-speed camera, fiber optics, and off-the-shelf components.
• Implementation of single-shot quantitative data processing utilizing spatial carrier frequency and Fourier analysis.
• Application of the system for supersonic compressible fluid discharge research in a wind tunnel.

Main Results:

• Demonstrated high sensitivity and accuracy in measuring density distributions with a spatial resolution of approximately 50 μm.
• Successfully captured important features of the supersonic fluid flow pattern.
• Achieved good agreement between experimental measurements and Computational Fluid Dynamics (CFD) simulations.

Conclusions:

• The developed interferometric technique is effective for sensitive and accurate compressible fluid flow research.
• The system's compactness, portability, and real-time processing capabilities make it suitable for aerodynamic laboratories.
• The technique provides valuable quantitative data for validating CFD models and understanding complex flow phenomena.