Laboratory-scale blast wave phenomena – optical diagnostics and applications

Analysis of Shock Wave Interaction with an Obstacle by Coupling Pressure Measurements and Visualization

“…The optical model of Edgerton [11] is the typical method used to visualize shock waves in a large field. Nevertheless, some optical setups make it possible to quantify the shock wave at the cost of some optical constraints or corrections [12][13][14][15][16]. A simple optical method is the pure in-line shadowscopy (PILS) method, also called retroreflective Edgerton shadowgraphy.…”

Frequency Bandwidth of Pressure Sensors Dedicated to Blast Experiments

“…However, the sensor bandwidth needed to accurately estimate the magnitude of the overpressure peak has surprisingly not yet been derived. According to [ 16 , 17 ], the bandwidth requirement differs in small-scale and large scale experiments. In [ 15 ], the bandwidth is assumed to be 50 times larger than the attenuation rate of the overpressure peak, but no method is provided to obtain the attenuation rate.…”

Quantitative Schlieren Measurement of Explosively‐Driven Shock Wave Density, Temperature, and Pressure Profiles

“…Many of the imaging studiesv isualize and track shock wave propagation using refractive imagingt echniquesi ncluding schlieren, shadowgraphy,a nd backgroundo riented schlieren (BOS) [5].I no ne of the most ground-breaking studies, Kleine et al used high-speed digital cameras and shadowgraphy to track shockw aves from silver azide charges and demonstrated the spatiald ependence of a" TNT equivalence" measurement [6].S imilar studiese xpanded the analysis using other imaging methods [7,8],explosive materials [9][10][11][12],a nd explosive-charges cales [13][14][15].A ll of these approaches have focusedo nm easuring the shock wave propagation opticallyt oe stimate pressure characteristics which are compared to gage measurements.…”

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1IntroductionCharacterizationo fe xplosivee ffects has traditionally been performed using pressure gages and various measures of damage,s uch as plate dents,t od eterminea"TNT Equivalence" of ab last [1,2].M ost of the traditional methods, however, result in numerouse quivalencies for the same material due to largeu ncertainties and dependencies of the equivalence on the distance from the explosion [3,4]. Modern high-speed digitali maging has allowed the development of several optical techniques for studyinge xplosive effects, which have expanded the detail to which ab last can be characterized.Many of the imaging studiesv isualize and track shock wave propagation using refractive imagingt echniquesi ncluding schlieren, shadowgraphy,a nd backgroundo riented schlieren (BOS) [5].I no ne of the most ground-breaking studies, Kleine et al used high-speed digital cameras and shadowgraphy to track shockw aves from silver azide charges and demonstrated the spatiald ependence of a" TNT equivalence" measurement [6].S imilar studiese xpanded the analysis using other imaging methods [7,8],explosive materials [9-12],a nd explosive-charges cales [13][14][15].A ll of these approaches have focusedo nm easuring the shock wave propagation opticallyt oe stimate pressure characteristics which are compared to gage measurements.The schlieren and BOS technique are capable of yielding quantitative density information of flow fields [16],b ut few researchers have applied this capabilityt os tudyinge xplosions. Quantitative density measurement from refractive techniques is well-documented for aerodynamics applications [17][18][19],i ncluding shock waves [20],b ut not moving shocks.

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