Title

Hybrid Optical-Flow-Cross-Correlation Method for Particle Image Velocimetry

Author

Salazar

Date of Award

12-2019

Degree Name

Master of Science in Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dr. Tianshu Liu

Second Advisor

Dr. Parviz Merati

Third Advisor

Dr. Javier M. Montefort

Keywords

Aerodynamics, experimental fluid dynamics, Particle Image Velocimetry, optical flow, aerospace engineering

Access Setting

Masters Thesis-Abstract Only

Restricted to Campus until

12-15-2029

Abstract

This thesis describes the development and validation of a hybrid optical-flow-cross-correlation method for the extraction of high-resolution velocity fields from particle images. The proposed method is developed to overcome the inherently limited spatial resolution of the cross-correlation method as well as the limitations of the optical flow method applied to PIV images with relatively large displacements. The main elements of the hybrid method include a cross-correlation scheme for initial estimation, a shifting scheme for generating a shifted image and an optical flow scheme for obtaining a refined high-resolution velocity field. Furthermore, a pre-processing scheme is used to correct illumination intensity changes in the particle images.

Validation of the hybrid method is done through simulations in a parametric space in comparison with cross-correlation and optical flow methods. Further quantitative comparisons are made using PIV images from a single and a twin jet. In addition, S-PIV images of a pair of delta wings are evaluated for comparison. Finally, cymatic particle images of Chladni patterns are analyzed using the hybrid method.

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