In Background – Oriented Schlieren (BOS), distortions of a pattern are used to characterize flow fields containing refractive gradients. In the process, they can lead to some uncertainty. We proposed a method to quantify one aspect of uncertainty – that introduced when the density gradient...
The value of the flowing soap film as an experimental platform depends on its ability to approximate the two-dimensional Navier-Stokes equation. A variety of experimental techniques have been applied to characterize the soap film patterns, with the measured quantities being the thickness and the velocity...
We propose an improved density integration methodology for Background Oriented Schlieren (BOS) measurements that overcomes the noise sensitivity of the commonly used Poisson solver. The method employs a weighted least-squares (WLS) optimization of the 2D integration of the density gradient field by solving an over-determined...
We present an uncertainty quantification methodology for density estimation from Background-Oriented Schlieren (BOS) measurements, in order to provide local, instantaneous, a posteriori uncertainty bounds on each density measurement in the field of view. Displacement uncertainty quantification algorithms from cross-correlation-based particle image velocimetry are used to...
We present a ray tracing image generation methodology for rendering realistic images of particle image velocimetry (PIV) and background oriented schlieren (BOS) experiments in the presence of density/refractive index gradients. This methodology enables the simulation of experiments for experimental design, error, and uncertainty analysis. Images...
Background-Oriented Schlieren (BOS) is used to measure fluid density from the apparent distortion of a target dot pattern. Here, we propose a new displacement estimation methodology based on tracking individual dots on the pattern as opposed to conventional cross-correlation algorithms. As dot patterns used in...
Background-Oriented Schlieren (BOS) is a technique used to measure fluid density from the apparent distortion of a target dot pattern. Here, we model how non-linearities in the density gradient fields can blur the dot pattern image and increase the position uncertainty. To develop this model,...