The Rectangular Wall Jet - Part II: Role of the Large-Scale Structures

2005 ◽  
Author(s):  
Joseph Hall ◽  
Dan Ewing
Keyword(s):  
Large Scale ◽  
Wall Jet ◽  
Large Scale Structures ◽  
Scale Structures

scholarly journals Cosmic Inflation, Quantum Information and the Pioneering Role of John S Bell in Cosmology

Universe ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 92 ◽  
Author(s):  
Jérôme Martin
Keyword(s):  
Quantum Mechanics ◽  
Quantum Information ◽  
Large Scale ◽  
Gravitational Instability ◽  
Cosmic Inflation ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Accuracy Data ◽  
Made In

According to the theory of cosmic inflation, the large scale structures observed in our Universe (galaxies, clusters of galaxies, Cosmic Background Microwave—CMB—anisotropy...) are of quantum mechanical origin. They are nothing but vacuum fluctuations, stretched to cosmological scales by the cosmic expansion and amplified by gravitational instability. At the end of inflation, these perturbations are placed in a two-mode squeezed state with the strongest squeezing ever produced in Nature (much larger than anything that can be made in the laboratory on Earth). This article studies whether astrophysical observations could unambiguously reveal this quantum origin by borrowing ideas from quantum information theory. It is argued that some of the tools needed to carry out this task have been discussed long ago by J. Bell in a, so far, largely unrecognized contribution. A detailled study of his paper and of the criticisms that have been put forward against his work is presented. Although J. Bell could not have realized it when he wrote his letter since the quantum state of cosmological perturbations was not yet fully characterized at that time, it is also shown that Cosmology and cosmic inflation represent the most interesting frameworks to apply the concepts he investigated. This confirms that cosmic inflation is not only a successful paradigm to understand the early Universe. It is also the only situation in Physics where one crucially needs General Relativity and Quantum Mechanics to derive the predictions of a theory and, where, at the same time, we have high-accuracy data to test these predictions, making inflation a playground of utmost importance to discuss foundational issues in Quantum Mechanics.

The Dynamics of the Large-Scale Turbulent Structures in the Impinging Round Jet

2003 ◽  
Author(s):  
Joseph W. Hall ◽  
Dan Ewing ◽  
Zhuyun Xu ◽  
Horia Hangan
Keyword(s):  
Large Scale ◽  
Wall Jet ◽  
Turbulent Structures ◽  
Azimuthal Mode ◽  
Large Scale Structures ◽  
Preferred Direction ◽  
Plate Spacing ◽  
Ring Structures ◽  
Instantaneous Pressure ◽  
Scale Structures

Experiments were performed to characterize the development of the large-scale structures in the stagnation and wall-jet regions of a turbulent impinging jet with a nozzle-to-plate spacing of 2 diameters and a Reynolds number of 20000. In particular, the instantaneous pressure was measured at 137 points on the wall using 6 concentric rings of pressure taps located 0.25, 0.5, 1.0, 1.5, 2.0 and 2.5 pipe diameters from the jet centreline. The 6 rings respectively contained 8, 16, 16, 32, 32 and 32 equally spaced taps as well as a single pressure tap placed at the jet centerline. The fluctuating pressure was decomposed into azimuthal modes and it was found that a significant portion of the field was contained in azimuthal mode 0 associated with the axisymmetric ring structures and azimuthal mode 1, often associated with jet precessing. The instantaneous pressure was filtered so that only azimuthal modes 0, 1 and −1 remained, and the dynamics of the large-scale structures associated with these modes was examined. These structures were found to be convected radially outward, were highly intermittent, and found to not rotate in a preferred direction.

The role of large scale structures in turbulent jets

1977 ◽  
Vol 20 (10) ◽  
pp. S290
Author(s):  
J. Laufer ◽  
F. K. Browand ◽  
R. A. Petersen
Keyword(s):  
Large Scale ◽  
Turbulent Jets ◽  
Large Scale Structures ◽  
Scale Structures

scholarly journals Large-scale Structures in the CANDELS Fields: The Role of the Environment in Star Formation Activity

2020 ◽  
Vol 890 (1) ◽  
pp. 7 ◽  
Author(s):  
Nima Chartab ◽  
Bahram Mobasher ◽  
Behnam Darvish ◽  
Steve Finkelstein ◽  
Yicheng Guo ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Large Scale Structures ◽  
Star Formation Activity ◽  
Scale Structures

scholarly journals The Theory of Large-Scale Structure of the Universe: Local Properties and Global Topology

1983 ◽  
Vol 104 ◽  
pp. 387-391
Author(s):  
A. G. Doroshkevich ◽  
S. F. Shandarin ◽  
Ya.B. Zeldovich
Keyword(s):  
Cellular Structure ◽  
Large Scale ◽  
Rest Mass ◽  
Large Scale Structure ◽  
Large Scale Structures ◽  
Global Topology ◽  
Local Properties ◽  
Scale Structures ◽  
The Universe

Properties of the large-scale distribution of galaxies are considered. Particular attention is paid to properties of the large-scale structures such as anisotropy of superclusters and the existence of large regions practically devoid of galaxies. Another question discussed in detail is the link between superclusters and formation of a network or cellular structure. An explanation of the latter is proposed in the frame of the fragmentation scenario. The role of the neutrino rest mass is discussed.

Large-scale motions in a plane wall jet

2019 ◽  
Vol 877 ◽  
pp. 239-281 ◽  
Author(s):  
Ebenezer P. Gnanamanickam ◽  
Shibani Bhatt ◽  
Sravan Artham ◽  
Zheng Zhang
Keyword(s):  
Reynolds Number ◽  
Shear Layer ◽  
Large Scale ◽  
Plane Wall ◽  
Shear Stresses ◽  
Wall Jet ◽  
Wall Region ◽  
Free Shear Layer ◽  
Large Scale Structures ◽  
Scale Structures

The plane wall jet (PWJ) is a wall-bounded flow in which a wall shear layer develops in the presence of extremely energetic flow structures of the outer free-shear layer. The structure of a PWJ, developing in still air, was studied with the focus on the large scales in the flow. Wall-normal hot-wire anemometry (HWA) measurements along with double-frame particle image velocimetry (PIV) measurements (wall-normal–streamwise plane) were carried out at streamwise distances up to $162b$, where $b$ is the slot width of the PWJ exit. The nominal PWJ Reynolds number based on exit parameters was $Re_{j}\approx 5940$. Comparisons with a zero-pressure-gradient boundary layer (ZPGBL) at nominally matched friction Reynolds number $Re_{\unicode[STIX]{x1D70F}}$ were also carried out as appropriate, to highlight key features of the PWJ structure. Consistent with previous work, the PWJ showed a dependence of the peak turbulent stresses on the jet exit Reynolds number. The turbulent production showed a peak corresponding to the near-wall cycle similar to the peak seen in the ZPGBL. However, another turbulent production peak was observed in the outer free-shear layer that was an order of magnitude larger than the inner one. Along with the change in sign of the viscous and Reynolds shear stresses, the PWJ was shown to have a region of very low turbulent production between these two peaks. The dissipation rate increased over the PWJ layer with a peak also in the outer region. Visualizations of the flow and two-point correlations reveal that the most energetic large-scale structures within a PWJ are vortical motions in the wall-normal–streamwise plane similar to those structures seen in free-shear layers. These structures are referred to as J (for jet) type structures. In addition two-point correlations reveal the existence of large-scale structures in the wall region which have a signature similar to those structures seen in canonical boundary layers. These structures are referred to as W (for wall) type structures. Instantaneous PIV realizations and flow visualizations reveal that these W type large-scale features are consistent with the paradigm of hairpin vortex packets in the wall region. The J type structures were seen to intrude well into the wall region while the W type structures were also seen to extend into the outer shear layer. Further, these large-scale structures were shown to modulate the amplitude of the finer scales of the flow.

scholarly journals Potential Role of the Entanglement Velocity of 1023 m·s-1 to Accommodate Recent Measurements of Large Scale Structures of the Universe

2014 ◽  
Vol 42 ◽  
pp. 106-112
Author(s):  
Michael A. Persinger ◽  
Stanley A. Koren
Keyword(s):  
Large Scale ◽  
Potential Role ◽  
Gravitational Constant ◽  
Rest Mass ◽  
Large Scale Structures ◽  
Inertial Frames ◽  
Order Of Magnitude ◽  
Scale Structures ◽  
The Universe

The aggregate of m7·s-1 from the product of the four geometric terms for increasing dimensions of a closed path (a circle) when set equal to the optimal combinations of the gravitational constant G and the universe’s mass, length and time results in a diffusivity term of 1023 m·s-1. Conversion of the total energy of the universe to volts per meter and Tesla results in a velocity of the same order of magnitude. The required f6 multiplication to balance the terms solves optimally for a frequency that when divided by the modified Planck’s value is the equivalent upper limit of the rest mass of a photon. Several experimental times associated with orbital distances for inertial frames are consistent with this velocity. Calculations indicate that during the final epoch the velocity from the energy derived from universal potential difference over length and magnetic fields will require only a unit frequency adjustment that corresponds to the energy equivalent of one orbit of a Bohr electron. We suggest that one intrinsic process by which large scale structures (Gigaparsec) are organized could involve this “entanglement velocity”. It would be correlated with the transformation of “virtual” or subthreshold values of the upper rest mass of photons to their energetic manifestation as the universe emerges from dark energy or matter that is yet to appear.

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