Shapes Of Jets Research Articles

Measurement of jet shapes in high-

The shapes of jets with transverse energies, $E_{\rm T}^{\rm jet}$ , up to 45 GeV produced in neutral- and charged-current deep inelastic $e^+p$ scattering (DIS) at $Q^2 > 100$ GeV $^2$ have been measured with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the $\eta$ - $\phi$ plane with a cone radius of one unit. The jets become narrower as $E^{\rm jet}_{\rm T}$ increases. The jet shapes in neutral- and charged-current DIS are found to be very similar. The jets in neutral-current DIS are narrower than those in resolved processes in photoproduction and closer to those in direct-photon processes for the same ranges in $E_{\rm T}^{\rm jet}$ and jet pseudorapidity. The jet shapes in DIS are observed to be similar to those in $e^+e^-$ interactions and narrower than those in $\bar{p}p$ collisions for comparable $E_{\rm T}^{\rm jet}$ . Since the jets in $e^+e^-$ interactions and $e^+p$ DIS are predominantly quark initiated in both cases, the similarity in the jet shapes indicates that the pattern of QCD radiation within a quark jet is to a large extent independent of the hard scattering process in these reactions.

The optical continua of extragalactic radio jets

view Abstract Citations (84) References (71) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Optical Continua of Extragalactic Radio Jets Keel, William C. Abstract Multicolor optical images have been used to measure the broad-band spectral shapes of radio jets known to show optical counterparts, and to search for such counterparts in additional objects. One new detection, the brightest knot in the NGC 6251 jet, is reported. In all cases, except part of the 3C 273 jet, the jet continua are well-represented by synchrotron spectra from truncated power-law electron distributions, with emitted-frame critical frequencies between 3 x 10^14^ and 2 x 10^15^ Hz. This may be due to fine structure in the jets or to the particle (re)acceleration process. Two hot spots (Pic A and 3C 303) differ from the jets, in showing unbroken power-law spectra from the radio to the B band. Image restoration has been used to examine the sub-arcsecond structure of the M87 jet and derived spectral shapes for various knots free of blending problems. The structure matches that seen in the radio to the 0.3" level, implying that the jet structure prevents particles from streaming freely over this distance (~30 pc). Significant changes in turnover frequencey occur from knot to knot, with an overall trend of higher frequency closer to the nucleus. Knot A is an exception, with a spectrum like the features near the core. An Appendix gives results of surface photometry for the program galaxies. Publication: The Astrophysical Journal Pub Date: June 1988 DOI: 10.1086/166400 Bibcode: 1988ApJ...329..532K Keywords: Active Galactic Nuclei; Astronomical Photometry; Color Photography; Extragalactic Radio Sources; Quasars; Radio Jets (Astronomy); Centimeter Waves; Radio Emission; Synchrotron Radiation; Astrophysics; GALAXIES: INDIVIDUAL MESSIER NUMBER: M87; GALAXIES: JETS; GALAXIES: PHOTOMETRY; QUASARS; RADIATION MECHANISMS; RADIO SOURCES: GALAXIES full text sources ADS | data products SIMBAD (15) NED (14)

Experimental investigation of low reynolds number flows of liquid‐liquid jets

AbstractThe shapes of liquid jets issuing from tubes into a second immiscible liquid are examined experimentally. Previous theoretical work is seen to be based on boundary layer theory and therefore not applicable to low Reynolds number jets as presented here. However, these works have provided insight into dimensionless parameters which could be important in governing this process. The experimental data is presented in the form of these dimensionless groups so that their significance can be explored.The results clearly show that the dispersed phase Reynolds number and the viscosity ratio of the two liquid jets are the most important parameters affecting jet shape. Non‐Newtonian elasticity is seen to contribute to jet expansion but not as much as in the case of inviscid jet swelling. The continuous phase is seen to have a component of velocity far from the jet surface unlike the assumption used in boundary layer theory.The boundary layer theory of Schlichting was extended to predict jet shapes for a viscosity ratio of one. It is seen that the theory does not apply within 15 dimensionless distances from the tube exit. Accurate predictions will require more precise evaluation of the equations of motion.

Liquid Jet Impingement Normal to a Disk in Zero Gravity

An experimental and analytical investigation was conducted to determine the free surface shapes of circular jets impinging normal to sharp-edged disks in zero gravity. Experiments conducted in a zero gravity drop tower yielded three distinct flow patterns which were classified in terms of the relative effects of surface tension and inertial forces. An order of magnitude analysis was conducted indicating regions where viscous forces were not significant when computing free surface shapes. The free surface analysis was simplified by transforming the governing potential flow equations and boundary conditions into the inverse plane. The resulting nonlinear equations were solved numerically and comparisons were made with the experimental data for the inertia dominated regime.

Penetration and Deflection of Jets Oblique to a General Stream

The dynamics of the entry of jets of fluid into a general stream at an oblique angle from slots and orifices is studied by means of a simplified two-dimensional potential flow analysis. The wake is approximated by an extensive area of dead fluid separated from the jet by a vortex sheet at uniform pressure. The jet is separated from the main stream by a stream line, and the jet velocity is restricted to one particular value so that there is no discontinuity across this stream line. Analysis using the conventional Helmholtz-Kirchhoff method leads to computations of the various relationships between the geometrical and velocity parameters. Calculations are also made of the shapes of jets in some common geometries. An equivalent analysis is made of the situation in which the trailing edge of the jet does not separate from the downstream wall, and the results are compared to the analysis with separation. The solution for the flow from a two-dimensional orifice is compared to experimental data for the roughly comparable case of flow from a circular orifice, and a qualitative agreement is shown. The results have a possible utility in serving as a skeletal structure of a more complete analysis of the mixing process in combustion chambers and cooling films. co = 4> + ix}/