Hypersonic heating computations are still challenging due to difficulties in “A) robust capturing of shockwaves” and “B) accurate prediction of heating.” Based on our numerical survey for A), we found that the dissipation inside the numerical shock wave structure (where no physical or mathematical explanation is valid) must be proportional to Mach number, in contrast to Mach independent dissipa...

A GaAs/A1GaAs traveling wave Mach-Zehnder electro-optic modulator with novel slow wave electrodes was fabricated on undoped epitaxial layers. Using appropriate electrode engineering velocity matching with matched impedance and low microwave loss was achieved. Device had a measured electrical bandwidth greater than 40 GHz at 1.55 j.un. The measured bandwidth at 1.3 j.m was 37 GHz. The mechanism ...

Interaction between the normal shock wave and the turbulent boundary layer in a supersonic nozzle becomes complex with an increase of a Mach number just before the shock wave. When the shock wave is strong enough to separate the boundary layer, the shock wave is bifurcated, and the 2nd and 3rd shock waves are formed downstream of the shock wave. The effect of a series of shock waves thus formed...

A cryogenic shock tube has been developed as a tool for research in fluid mechanics and low-temperature physics. The shock tube was designed to operate with the test section immersed in a cryogenic liquid. A unique diaphragm-changing mechanism makes this shock tube an economical and practical device. There are several advantages in operating a shock tube at cryogenic temperatures. Shock waves o...

Submitted for the DFD10 Meeting of The American Physical Society Simulation of Strong Shock and Turbulence Interactions using High-Order Shock-Fitting Algorithms1 PRADEEP RAWAT, XIAOLIN ZHONG, University of California Los Angeles — We present results for Direct Numerical Simulations (DNS) of interactions of shock waves with realistic isotropic turbulence using shock-fitting schemes that are hig...

The behaviour of an initially planar shock wave propagating into a linearly convergent wedge is investigated experimentally and numerically. In the experiment, a 25◦ internal wedge is mounted asymmetrically in a pressure-driven shock tube. Shock waves with incident Mach numbers in the ranges of 1.4–1.6 and 2.4–2.6 are generated in nitrogen and carbon dioxide. During each run, the full pressure ...

We introduce a numerical model for the simulation of nuclear flames in Type Ia supernovae. This model is based on a low Mach number formulation that analytically removes acoustic wave propagation while retaining the compressibility effects resulting from nuclear burning. The formulation presented here generalizes low Mach number models used in combustion that are based on an ideal gas approxima...

Edges are key points of information in visual scenes. One important class of models supposes that edges correspond to the steepest parts of the luminance profile, implying that they can be found as peaks and troughs in the response of a gradient (1st derivative) filter, or as zero-crossings in the 2nd derivative (ZCs). We tested those ideas using a stimulus that has no local peaks of gradient a...

Plate impact experiments are a powerful tool in equation of state (EOS) development, but are inherently limited by the range of impact velocities accessible to the gun. In an effort to dramatically increase the range of pressures which can be studied with available impact velocities, a new experimental technique is being developed. The possibility of using a confined converging target to focus ...