We study shock formation in vertically oscillated granular layers, using both molecular dynamics simulations and numerical solutions of continuum equations to Navier-Stokes order. A flat layer of grains is thrown up from an oscillating plate during each oscillation cycle and collides with the plate later in the cycle. The collisions produce layer compaction near the plate and a high temperature...

Understanding of the three-dimensional shock wave-vortex loop interaction phenomena plays a key role in noise reduction. This study focuses on the three-dimensional shock wave distortion and propagation phenomena in a near-field supersonic jet. Shock-square vortex loop interaction was experimentally investigated in a square cross-sectional open-end shock wave generating tube at an incident shoc...

We now apply the model predictive control (MPC) of speed limits that we have presented in previous publications [1], [2] to a calibrated METANET model of a 19 km stretch of the real-world freeway A1 in The Netherlands. This freeway regularly suffers from shock waves originating mainly from onramps, and speed limits are now used to suppress these shock waves. First, we calibrate and validate the...

In his 2007 monograph, D. Christodoulou proved a breakthrough result giving a complete description of the formation of shock waves, starting from small, regular initial conditions, in solutions to the relativistic Euler equations. In 2014, Christodoulou–Miao extended the result to the nonrelativistic compressible Euler equations. In both works, the assumptions on the initial conditions caused t...

the new non-conventional cutting process by the use of thermal shock is a convenient procedure for cutting the brittle materials such as glasses and ceramics. this method is based on the application of localized thermal shock to brittle materials by the use of hot air jet, which induces thermal stresses at the tip of an existed pre-crack. due to the thermo-elastic behavior of materials, the pre...

Experiments were performed to analyze the interaction of an explosively driven shock wave and a propane flame. A 30 g explosive charge was detonated at one end of a 3-m-long, 0.6-m-diameter shock tube to produce a shock wave which propagated into the atmosphere. A propane flame source was positioned at various locations outside of the shock tube to investigate the effect of different strength s...

Shock tubes have been widely used since the 1950s to study physical phenomena such as shock waves, combustion chemistry, and the response of materiel to blast loading. Recently, laboratory-scale shock tubes driven by oxy-acetylene were described. It was estimated that these shock tubes would not have a significant “jet effect” of expanding gases following the shock front because the combustion ...

It is shown that collisionless shock waves can be driven in unmagnetized electron-positron plasmas by performing a two-dimensional particle-in-cell simulation. At the shock transition region, strong magnetic fields are generated by a Weibel-like instability. The generated magnetic fields are strong enough to deflect the incoming particles from upstream of the shock at a large angle and provide ...

In this paper, two-dimensional (2-D) hybrid simulations are performed to investigate ion dynamics at a rippled quasi-parallel shock. The results show that the ripples around the shock front are inherent structures of a quasi-parallel shock, and the reformation of the shock is not synchronous along the surface of the shock front. By following the trajectories of the upstream ions, we find that t...

Shock ripples and shock–discontinuity interactions (SDIs) have long been proposed to explain the frequent occurrence of high-speed jets (HSJs) in magnetosheath; however, there is no direct observational evidence for either them occurring near a shock. Herein, we report large-scale, long-duration undulated quasi-perpendicular shock surface that capable generating HSJs. Based on curvatures estima...