Plasma induced flow field modification is studied experimentally using non-equilibrium DC surface discharge in a Mach 3 supersonic flow. An array of small pin electrodes (φ = 3/32”) is used in streamwise plasma discharge configuration. The schlieren imaging shows that an oblique shock can be obtained with a volumetric glow discharge on the cathode with a relatively low current (as low as 50 mA)...

This chapter introduces techniques for the capture and efficient display of dynamic three-dimensional non-stationary gas flows. We describe a flexible Schlieren-tomographic system consisting of multiple consumer camcorders. A special choice of background pattern for Background Oriented Schlieren (BOS) imaging provides for flexibility in the experimental setup. Optical flow techniques are used t...

Schlieren interferometry is found to be an alternative tool for temperature measurement during thermoplastic laser welding with regard to methods based on thermocouples or optical pyrometers. In fact, these techniques are not easily applied when materials to be processed have reduced thickness, negligible heat conduction, and low emissivity, as is the case of welding high-density polyethylene f...

A method is described for measuring the density distribution in an inhomogeneous medium. This method is based upon the classical Schlieren technique, known as Background Oriented Schlieren (BOS) method. The method measures the density dependence of the refractivity through the detection of the deflecting angle of a number of light beams passing through the space to be measured. The results of s...

Center for Molecular Cardiology, University of Zurich, Wagistrasse 12, Schlieren CH-8952, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; Institute for Biomedical Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), Zurich, Switzerland; Department of Neurology, San Raffaele Scientific Institute, Milan, Italy; Division o...

• The fast transient ignition process of impinging flames was investigated experimentally. fuel composition varied from pure methane to 60% hydrogen enriched. High speed color/schlieren images were taken for flame and flow field visualization. velocity estimated using a novel schlieren velocimetry algorithm. relative between the also resolved. characteristics enriched diffusion are Keeping tota...

We investigate the usage of a Schlieren imaging setup to measure geometrical dimensions plasma channel in atomic vapor. Near resonant probe light is used image tenuous vapor and machine learning techniques are tested for extracting quantitative information from images. By building database simulated signals with range parameters training Deep Neural Networks, we demonstrate that they can extrac...

The traditional arrangement for visualizing optical phenomena with the schlieren technique is modified to include a Mach-Zehnder geometry. This allows for the implementation of two independent knife edges along two different beam paths, resulting in an enhanced combined image that is uniquely adjustable. Post-processed combined images are also generated by spatially separating the paths from ea...

We used a form of schlieren interferometry to measure the mean-squared amplitude and temporal autocorrelation function of concentration fluctuations driven by the presence of a gradient during the free diffusion of a urea solution into water. By taking and processing sequences of images separated in time by less than the shortest correlation time of interest, we were able to simultaneously meas...