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 present gauge invariant spectral Cauchy characteristic extraction. We compare gravitational waveforms extracted from a head-on black hole merger simulated in two different gauges by two different codes. We show rapid convergence, demonstrating both gauge invariance of the extraction algorithm and consistency between the legacy Pitt null code and the much faster Spectral Einstein Code (SpEC)....

A brief summary of the properties of astrophysical black holes is presented. Various modes of accretion are distinguished, corresponding to accretion at rates from well below to well above the Eddington rate. The importance of mass loss is emphasized when the accreting gas cannot radiate and it is asserted that a strong wind is likely to be necessary to carry off mass, angular momentum and ener...

We compute the gravitational self-force (or “radiation reaction” force) acting on a particle falling radially into a Schwarzschild black hole. Our calculation is based on the “mode-sum” method, in which one first calculates the individual l-multipole contributions to the self-force (by numerically integrating the decoupled perturbation equations) and then regularizes the sum over modes by apply...

What are the implications if the total ’information’ in the universe is conserved? Black holes might be ’logic gates’ recomputing the ’lost information’ from incoming ’signals’ from outside their event horizons into outgoing ’signals’ representing evaporative or radiative decay ’products’ of the reconfiguration process of the black hole quantum logic ’gate’. Apparent local imbalances in the inf...

We imagine the strings on the strectched horizon of any d space-time dimensional black hole to be bits of polymer. Then, proposing an interaction between these bits we obtain the size of the configuration, and thus of the black hole, using the scaling laws. The transition from a typical black hole state to a typical string state has a simple explanation, which also holds for the extremal black ...

Traditional mechanical control systems in thrust vectoring are efficient in rocket thrust guidance but their costs and their weights are excessive. The fluidic injection in the nozzle divergent constitutes an alternative procedure to achieve the goal. In this paper, we present a 3D analytical model for fluidic injection in a supersonic nozzle integrating an orifice. The fluidic vectoring uses a...

The production of small fluid droplets relies on an instability of solutions to the Young-Laplace equation. We ask whether smaller droplets can be produced by changing the shape of the nozzle. At a given critical pressure, the circular nozzle actually produces the largest droplet. The droplet volume can be decreased by up to 18% using a triangular nozzle with stretched corners.

Direct numerical simulation (DNS) and dynamic mode decomposition (DMD) are used to study the shear layer characteristics of a jet in a crossflow. Experimental observations by Megerian et al. (J. Fluid Mech., vol. 593, 2007, pp. 93–129) at velocity ratios (R = vj/u∞) of 2 and 4 and Reynolds number (Re = vjD/ν) of 2000 on the transition from absolute to convective instability of the upstream shea...

Robust manufacturing of micro parts at high throughput needs tailored concepts and methods to assure unchanging work piece quality. An actual challenge is the dimensional metrology with meso-to-microscopic high-aspect ratio features of micro-system components, e.g. micro gears for watches and micro motors, ferrules of optical fibers, hollow microneedles for painless drug delivery into living ce...