Improvements on the accuracy of derivative estimation from DPIV velocity measurements

Accuracy of out-of-plane vorticity estimation from in-plane experimental velocity measurements is investigated with particular application to digital particle image velocimetry (DPIV). Simulations of known flow fields are used to quantify errors associated with amplification of the velocity measurement noise and method bias error due to spatial sampling resolution. A novel, adaptable, hybrid estimation scheme combining implicit compact finite difference and Richardson extrapolation schemes is proposed for improved vorticity estimation. The scheme delivers higher-order truncation error with less noise amplification than an explicit second order finite difference scheme. Finally, a complete framework for predicting, a priori, the random, bias, and total error of the vorticity estimation on the basis of the error of the resolved velocities and the choice of differentiation scheme is developed and presented. A portion of this work was presented at ASME IMECE 2003 conference An erratum to this article is available at .