As a mature flow field measurement technology, particle image velocimetry (PIV) has been widely used to calculate the instantaneous motion of particles by identifying and comparing the positions of tracer particles between successive image frames. Measurement of the ambient air velocity distributions around fuel spray has been accomplished using LIF-PIV. However, due to the need to accurately identify the tracer particles, PIV is limited in its applications, such as measuring the flow field in turbid media. Optical flow calculates apparent velocities of movement of brightness patterns in an image and has been extensively used in computer vision. Different from PIV, optical flow segments images into regions that correspond to different objects without require of tracer particles. Since it is based on brightness patterns, the optical flow may be widely used in measuring flow field in the area of fuel spray and in-cylinder combustion cooperating with various relevant methods. To check the accuracy and robustness of optical flow, this study will calculate the 2-dimensional velocity fields of the same PIV image sequences using iterative optical flow and PIV respectively. Using PIV results as criteria, similarities and uncertainties of the velocity fields derived from the optical flow are acquired and the accuracy of the optical flow method can be validated.


Accuracy Verification of 2-Dimensional Velocity Field Derived From Optical Flow With Respect to PIV Flow Field Measurement

Division / Sponsors: 
Internal Combustion Engine Division (ICED)

Paper Proceedings: https://asmedigitalcollection.asme.org/ICEF/ICEF2020/volume/84034

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