Effect of Feedback Data Rate in PIV Measurement-Integrated Simulation*

This paper deals with measurement-integrated (MI) simulation, which is based on the observer in dynamical system theory to obtain the exact and detailed information of real flows. In this study, we propose the MI simulation coupled with Particle Image Velocimetry (PIV) for a flow with the Karman vortex street behind a square cylinder at Reynolds number of 1200 based on the cylinder width. The validity of the PIV-MI simulation is first examined in two-dimensional numerical experiment. The effect of feedback data rate is investigated by changing the feedback frequency and the feedback area. Then effectiveness of the PIV-MI simulation is validated in experiment. As a result, the PIV-MI simulation with full feedback shows good agreement with the standard solution for both the mean velocity and the velocity fluctuation. From the viewpoint of the reduced feedback data rate, spatially limited feedback shows better results than temporarily limited feedback. It is also confirmed that the information around the cylinder is important to reproduce the wake behind the cylinder. In the result of the experimental validation, the PIV-MI simulation reproduces the experimentally obtained flow field, showing the same effect of the feedback in accordance with the numerical experiment.

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