Journal Article

Theoretical formulation of streak failure conditions and numerical investigation to optimize the illumination code of particle streak velocimetry

Tsukamoto, Yusaku, Funatani, Shumpei

2023

Overview

In a typical coding method for particle streak velocimetry, the streak shape is divided into two dots and one line by controlling the illumination timing. In this study, several parameters were formulated to optimize the streak shape in a uniform flow using a theoretical approach. In contrast, for non-uniform flows, the formulation of optimal conditions does not provide a common criterion for all flow fields. Therefore, we developed a streak simulation technique based on a two-dimensional flow field and investigated a numerical approach to identify the optimization conditions for non-uniform flows. The test flow fields considered were the Couette flow, von Karman vortex, and Rankine vortex, with the streak number considered one of the parameters affecting the failure of the streak shape, increasing from 100 to 1300. In addition, another parameter, the magnification factor acting on the mean velocity of the flow field, was increased from 0.2 to 1.2. Furthermore, five types of streak failure factors were identified and analyzed based on their frequency of occurrence. The results of the two-dimensional streak simulation showed that the condition for maximizing the number of non-failure streaks for each flow field was successfully identified, and an estimation of the optimal illumination time was obtained. Additionally, vector densities of 0.001 vectors per pixel were achieved for the von Karman and Rankine vortices. The streak simulation can be an effective tool for evaluating the availability of PSV. Graphical abstract

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: 3-D graphics / Algorithms / Asymmetry / Cameras / Classical and Continuum Physics / Computer Imaging / Couette flow / Engineering / Engineering Fluid Dynamics / Engineering Thermodynamics / Failure / Fluid flow / Heat and Mass Transfer / Illumination / Investigations / Light / Mathematical analysis / Measurement techniques / Methods / Nonuniform flow / Optimization / Parameters / Pattern Recognition and Graphics / Regular Paper / Simulation / Transistors / Two dimensional flow / Velocimetry / Velocity / Vision