Background Oriented Schlieren (BOS) is an image-based density measurement technique. BOS estimates the gradient from apparent distortion of a target pattern viewed through medium with varying using cross-correlation, tracking, or optical flow algorithms. The can then be numerically integrated to yield spatially resolved estimate [1]. A method was recently proposed a-posteriori instantaneous and...

’Moon-Glade’ Background Oriented Schlieren method for measuring liquid surface deformations was used. The is based on the analysis of background dots pattern images reflected from surface. a transparent polyester film with dots, which located at certain distance above liquid. Compared to other methods that use image, this technique has following advantages: (1) it allows restoring instantaneous...

Understanding the mixing process of under-expanded gaseous-fuel jets from an outward opening injector is essential for developing Direct Injection (DI) internal combustion engines. This paper presents a Large-Eddy Simulation (LES) study DI methane into Constant Volume Chamber (CVC), considering full, geometry prototype injector. Four cases at conditions relevant to Compressed Natural Gas (CNG) ...

Accurate measurement of high-amplitude, broadband shock pulses in air is an important part of laboratory-scale experiments in atmospheric acoustics. Although various methods have been developed, specific drawbacks still exist and need to be addressed. Here, a schlieren optical method was used to reconstruct the pressure signatures of nonlinear spherically diverging short acoustic pulses generat...

In this work, we try to find the best setting of Computational Fluid Dynamic solver available for the problems in the field of supersonic internal flows. We used the supersonic air-toair ejector to represent the typical problem in focus. There are multiple oblique shock waves, shear layers, boundary layers and normal shock interacting in the supersonic ejector making this device typical in fiel...

Known since antiquity, ball lightning is a natural, long-lived plasma-like phenomenon associated with thunderstorms and is not well understood due to its rarity and unpredictability. A recently discovered laboratory phenomenon with striking similarity to ball lightning is observed when a high-power spark is discharged from a cathode protruding from a grounded electrolyte solution. Whereas sever...

Transient electric fields, which are an important but hardly explored parameter of laser plasmas, can now be diagnosed experimentally with combined ultrafast temporal resolution and field sensitivity, using femtosecond to picosecond electron or proton pulses as probes. However, poor spatial resolution poses great challenges to simultaneously recording both the global and local field features. H...