Analysis of Impact of Uncertainty in a Method for Determining Drag from Wake Velocity Profiles

Abstract

A previously published method for determining the drag of bodies in nominally two-dimensional flows is reviewed. The method relies on the fitting of parameters to wake velocity profiles rather than the integration of the profiles, and then additional fitting of the streamwise development of those parameters. The method does not lend itself to traditional uncertainty analysis techniques, so a Monte Carlo method is used to determine the uncertainty in the final drag coefficient based on the uncertainty in the initial velocity measurements. The effect of the level of uncertainty in the velocity measurements on the uncertainty of the drag coefficient is explored. The implications on the results if the wake velocities are measured using particle image velocimetry measurements are discussed.