Assessment of some experimental and image analysis factors for background oriented schlieren measurements

摘要

Quantitative measurements of fluid flow properties can be achieved bybackground oriented schlieren. In this paper it is shown that this depends onseveral factors. Image quality index is used to investigate the influence ofthe image sensor and the quality of its output. Image evaluation is applied tosynthetic images which are treated with a step function, so that they simulatethe sharp density jump. The gradual change of the evaluated vector shiftrevealed the major dependence on the interrogation window, and less so on thebackground features. BOS applied to shock wave reflection from a wedge in ashock tube gave qualitative results, due to large uncertainties. But, theapplication to cooling by natural convection gave satisfactory results,comparable to thermocouple data and theory.