Statistical Approach to the Measurement of Velocity Field

Article type: Research Article

Authors: Nishio, S. | Okuno, T.

Affiliations: Department of Marine System Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531 Japan

Abstract: Present paper describes the principle and applications of a velocity measurement using statistical analysis of visualized flow images. The authors have developed a new algorithm for the measurement using the passing probability of a particle. It is known that this kind methods gives the total flow speed at each pixel unit. In this study, the method is extended by forming the governing equation using the Lagrange's differentiation. The process is similar to the so-called spatio-temporal derivative method. The extension of the equation enables to measure the velocity components with the help of the statistical technique. The idea is based on the fact that the temporal derivative of luminance function is proportional to the vector product of the flow velocity and the gradient of luminance function in space which gives the velocity component normal to the edge of particle image. This is easy to apply on the three-dimensional flow field.

Keywords: PIV, wake measurement, flow velocity measurement, spatio-temporal derivative, statistical analysis

Journal: Journal of Visualization, vol. 1, no. 2, pp. 161-170, 1998