Showing papers on "Transverse plane published in 1997"

Velocity Measurements of a Jet Injected into a Supersonic Crossflow

Abstract: This paper presents a quantitative, experimental study of a single, sonic, underexpanded, transverse, round jet injected into a Mach 1.6 crosse ow. This investigation is applicable to studies of supersonic combustors, thrust vector control of rocket nozzles, the cooling of nozzle walls, and jet reaction force prediction. Schlieren/shadowgraph photography and two-component, frequency preshifted laser Doppler velocimetry are used to visualize the e ow and to measure three mean velocity components, e ve of the six kinematic Reynolds stresses, and turbulent kinetic energy at over 4000 locations throughout the e owe eld. The study focuses on the transverse, midline plane and on two crosse ow planes. These measurements are used to study the size and orientation of the recirculation regions upstream and downstream of the jet; the structure and strength of the bow shock, barrel shock, and Mach disk; the structure, strength, and development of the kidney-shaped, counter-rotating vortex pair; the growth of the annular shear layer between the jet plume and the crosse ow; and the growth of the boundary layer beneath the jet. In addition, the present study provides validation data for analytical and numerical predictions of the transverse jet e owe eld.

Transverse velocity increments in turbulent flow using the RELIEF technique

Abstract: Non-intrusive measurements of the streamwise velocity in turbulent round jets in air are performed by recording short-time displacements and distorsions of very thin tagging lines written spanwise into the flow. The lines are written by Raman-exciting oxygen molecules and are interrogated by laser-induced electronic fluorescence (relief). This gives access to the spatial structure of transverse velocity increments without recourse to the Taylor hypothesis. The resolution is around 25 μm, less than twice the Kolmogorov scale η for the experiments performed (with Rλ≈360–600).The technique is validated by comparison with results obtained from other techniques for longitudinal or transverse structure functions up to order 8. The agreement is consistent with the estimated errors – a few percent on exponents determined by extended-self-similarity – and indicates significant departures from Kolmogorov (1941) scaling.Probability distribution functions of transverse velocity increments Δu over separations down to 1:8η are reported for the first time. Violent events, with Δu comparable to the r.m.s. turbulent velocity fluctuation, are found to take place with statistically significant probabilities. The shapes of the corresponding lines suggest the effect of intense slender vortex filaments.

Compressibility effects in supersonic transverse injection flowfields

Abstract: The flowfields created by transverse injection of sonic gaseous jets through a circular nozzle into a supersonic crossflow have been experimentally investigated using planar Rayleigh/Mie scattering from silicon dioxide particles seeded into the crossflow stream. Helium and air were used as injectant gases allowing an examination of the effects of compressibility on the large-scale structural development and near-field mixing characteristics present within the flowfield. Instantaneous images from end and side view image planes show a highly three-dimensional interaction dominated by both large- and small-scale vortices. Analyses of these image ensembles provide jet spreading and penetration characteristics, standard deviation statistics, large-scale mixing information, and two-dimensional spatial correlation fields. Results indicate that injectant molecular weight variations do not strongly affect the jet’s transverse penetration into the crossflow, although they lead to substantially different compressibi...

Solid state optical data reader using an electric field for routing control

Abstract: An optical beam routing apparatus is constructed of solid material in which is embedded a beam routing array structure (1370) which has at least a first waveguide segment (1376) traversing the solid material along a plane, second waveguide segments (1378) traversing the solid material along the same plane and encountering the first waveguide segment at a plurality of intersections, electrically-controlled gratings 1372, 1373) disposed transverse to the intersections to controllably reflect optical energy between the first waveguide segment and the second waveguide segments, and optical reflectors (1374, 1375) at selected locations in line with the second waveguide segments (1378) for projecting optical energy into and/or out of the plane from a selected position (1382) on an-out-of-plane medium which might contain optically readable or writable information, such as a disc. Electrodes at the intersections and the electrically-controllable gratings (1372, 1373) disposed transverse of the intersections and controlled by the electrodes controllably reflect optical energy between the first waveguide segment and the second waveguide segment upon application of a controlled electric field at the electrodes.

Measurement of ultrasonic forces for particle–liquid separations

Abstract: The magnitude and direction of the ultrasonic radiation forces that act on individual particles in a standing-wave field were determined using a microscope-based imaging system. The forces are calculated from measured particle velocities assuming that the drag force, given by Stokes' law, is exactly counterbalanced by the imposed ultrasonic forces. The axial primary radiation force was found to vary sinusoidally with axial position and to be proportional to the local acoustic energy density, as predicted by theory. The magnitude of the transverse primary force was determined by two independent methods to be about 100-fold weaker than the axial force. Separation concepts exploiting the transverse force for cell retention have been successful despite the great disparity in magnitude between the axial and transvers-force components. This may be explained by the reduced hydrodynamic forces on aggregated particles in transverse flow due to their alignment in the sound field.

Proton and pion production relative to the reaction plane in Au + Au collisions at 11A GeV/c

Abstract: Results are presented of an analysis of proton and charged pion azimuthal distributions measured with respect to the reaction plane in Au + Au collisions at a beam momentum of about 11A GeV/c. The azimuthal anisotropy is studied as a function of particle rapidity and transverse momentum for different centralities of the collisions. The triple differential (in rapidity, transverse momentum, and azimuthal angle) distributions are reconstructed. A comparison of the results with a previous analysis of charged-particle and transverse energy flow as well as with model predictions are presented. {copyright} {ital 1997} {ital The American Physical Society}

Energy and charged particle flow in 10.8A GeV/c Au+Au collisions

Abstract: Experimental results and a detailed analysis are presented of the transverse energy and charged particle azimuthal distributions measured by the E877 Collaboration for different centralities of Au+Au collisions at a beam momentum of 10.8A GeV/c. The anisotropy of these distributions is studied with respect to the reaction plane reconstructed on an event-by-event basis using the transverse energy distribution measured by calorimeters. Results are corrected for the reaction plane resolution. For semicentral events we observe directed flow signals of up to 10{percent}. We observe a stronger anisotropy for slow charged particles. For both the charged particle and transverse energy distributions we observe a small but nonzero elliptic anisotropy with the major axis pointing into the reaction plane. Combining the information on transverse energy and charged particle flow we obtain information on the flow of nucleons and pions. The data are compared to event generators and the need to introduce a mean field or nucleon-nucleon potential is discussed. {copyright} {ital 1997} {ital The American Physical Society}

Volume shrinkage in slant fringe gratings of a cationic ring-opening holographic recording material : Holography III

Abstract: A new photopolymer holographic recording material, ULSH-500, based on cationic ring-opening polymerization, has been further optimized to achieve low transverse shrinkage without sacrificing sensitivity. The extent of transverse (z) and lateral (x) shrinkage was determined explicitly in this study for a range of slant angles in volume holograms recorded to near saturation and in holograms of low diffraction efficiency. The values ΔK x /K x and ΔK z /K z , which represent the physical material shrinkage in the grating vector plane, were ascertained by (1) direct measurement of the differential angle changes in the reference and signal beam angles necessary to achieve Bragg matching and (2) measurement of the average refractive index. The accuracy of this method was primarily limited by the exactness in determining the angle of peak efficiency in the Bragg selectivity curve. It is demonstrated that the peak angle can be established to within a small fraction of a degree. It is shown that the assumption of anchoring and, thus, uniaxial shrinkage as embodied in the conventional fringe rotation model cannot be applied for the photopolymer ULSH-500 under the recording conditions used herein. It is demonstrated that background uplift in angular selectivity profiles can be attributed to nonuniformity in the grating strength throughout the transverse direction of the recording media, and that the uplift can be reduced to negligible levels by using a low fluence pre-imaging exposure. Calorimetric analysis of reaction kinetics was performed using direct laser irradiation delivered by optical fiber.

Transverse ply cracking in cross-ply CFRP laminates - Initiation or propagation controlled?

Abstract: The initiation and propagation stages of transverse ply cracking in crossply CFRP laminates under quasi-static loading have been studied using laminates with a range of transverse ply thicknesses. Specimens of two types have been tested-coupons with polished edges and coupons with defects (notches) introduced into the transverse ply prior to testing. Detailed observations of crack propagation across the transverse ply thickness and width have been made, along with measurements of crack density and residual properties. In laminates with thin transverse plies (less than 0.25 mm for the materials tested here), fully formed transverse cracks are observed at about the same strain in undamaged and notched laminates. In laminates with thicker transverse plies (greater than 0.25 mm), the notched laminates show fully formed transverse cracks at lower strains than the undamaged laminates. The experimental results have illustrated the situations (laminate properties, presence of flaws) in which fracture mechanics mo...

Lateral-Torsional Buckling of Singly Symmetric I-Beams

Abstract: Finite-element buckling analyses of singly symmetric I-shaped girders subjected to transverse loading applied at different heights on the cross section were conducted. Single-curvature and reverse-curvature bending were considered. Moment gradient factors based on the finite-element results were calculated and compared with traditional values used to predict the buckling capacity of I-shaped doubly symmetric sections. The results from the computational study show that, for many cases, traditional moment gradient factors can be used for singly symmetric girders if effects of load height are measured relative to midheight of the cross section. Solutions for load-height effects are presented for singly symmetric I-sections.

Compressible magnetohydrodynamic Kelvin–Helmholtz instability with vortex pairing in the two-dimensional transverse configuration

Abstract: For a two-dimensional (2-D) transverse configuration, where the plasma motion occurs in a 2-D plane transverse to the magnetic field, the nonlinear evolution of the magnetohydrodynamic (MHD) Kelvin–Helmholtz (K–H) instability is investigated by means of a 2-D MHD simulation for a convective fast magnetosonic Mach number 0.35, which is defined for the total jump of the flow velocity. The compressibility and the nonzero baroclinic vector are shown to violate the conservation of the enstrophy for the 2-D MHD transverse configuration and for the 2-D fluid motion. After the nonlinear saturation of the linearly fastest growing vortices, the vortices continue to coalesce until no more vortex pairing is allowed, owing to a finite length of the simulation system. The plasma inside the vortex is rarefied strongly by the fast magnetosonic rarefaction and each vortex is associated with an eddy current, which is inertia current in nature. The plasma flow velocity is enhanced at the periphery of the vortex and the net momentum transport and shear relaxation by the instability occur as long as the vortex pairing continues. Anomalous viscosity by the K–H instability increases with the vortex pairing and its increase is due to the growth of subharmonic modes.

Apparatus and method for determining movements and velocities of moving objects

Abstract: With an apparatus according to the invention it is possible to detect an object's velocity transverse to the direction of propagation of an interacting field. Such transverse movement is detected by applying a field that oscillates spatially in the transverse direction. The method used in the apparatus is applicable where wave energy is used to sense or detect an object by its scattering properties when using either sound waves or electro-magnetic waves. The movement can be detected according to the field properties. The field represented by the sampling pulse must feature a spatial oscillation in the directions, where the velocity components are of interest. Such a transversely oscillating field is e.g. generated by using apodization on individual transducer elements and a special focusing scheme. The apparatus uses waves of either sound or electro-magnetic radiation.

Device and method for producing osteotomies

Abstract: Devices and methods for producing minimally invasive osteotomies to correct angular deformities of bones in and about the knee are disclosed. The method includes locating a plane in which the angle exhibited by the deformity is situated. An oblique cut is then made along a surface of the bone, such that the cut is transverse to the plane in which the angle is situated. Thereafter, the bone pieces are rotated about the cut relative to one another until a desired alignment between the bone pieces is achieved. To maintain the bone pieces in alignment, a device having an elongated body for extending into a tunnel between the bone pieces is provided. The device also includes a rigid member fixedly positioned at one end of the body. The rigid member is transverse to the body to engage one bone piece. The device further includes a locking mechanism at an opposite end of the body to engage the other bone piece. The device permits the bone pieces to be pulled against one another between the rigid member and the locking mechanism.

Machine for mowing and chopping maize and suchlike stalk crops

Abstract: The machine works independently of the rows of maize and similar stem type crops, having two ro more tined mowing and intake drums each side of the vertical central plane at which the chopping mechanism with intake drums is situated. The drums are supplied via passages formed between vertical walls. In plan view, the walls (22) run in an undulating pattern on both sides of the central plane. Their trough portions (23) following the peripheries (30) of the intake and mowing drums (6-8). At each intervening crest (24) is a transverse conveyor drum (25) with protruding tines and on a vertical axis, the tines protruding through the wall (22) into the passage. The undulations in the walls can form a flat sinusoidal curve. The innermost intake and mower drums closest to the central plane can be of the same diameter, with their axis in a common transverse plane.

Operating element arrangement with articulated arcuate operating element for controlling motor vehicle longitudinal and transverse movement

Abstract: The operating element is arcuate and is articulated in a lower driver's seat region pivotably about a transverse control axis located on the longitudinal side of the vehicle for controlling the transverse movement of the vehicle. The element is also movable in the longitudinal direction of the vehicle for controlling the vehicle longitudinal movement. The element extends upwards from the lower seat region, on at least one side of the driver's seat, laterally past the adjacent seat cushion and terminates in a end handle. This arrangement provides an ergonomically favorable and reliable operating element so as to dispense with a steering wheel, a brake and accelerator pedal assembly.

Modal analysis of cracked, unidirectional composite beam

Abstract: In this paper, a model and an algorithm for creation of the characteristic matrices of a composite beam with a single transverse fatigue crack are presented. The element developed has been applied in analysing the influence of the crack parameters (position and relative depth) and the material parameters (relative volume and fibre angle) on changes in the first four transverse natural frequencies of the composite beam made from unidirectional composite material.

Nonlinear Oscillations of a Nonresonant Cable under In-Plane Excitation with a Longitudinal Control

Abstract: The nonlinear oscillations of a controlled suspended elastic cable under in-plane excitation are considered. Active control realized by longitudinal displacement of one support is introduced in order to reduce the transverse in-plane and out-of-plane vibrations. Linear and quadratic enhanced velocity feedback control laws are chosen and their effects on the cable motion are investigated using a two degree-of-freedom model. Perturbation analysis is performed to determine the in-plane steady-state solutions and their stability under an out-of-plane disturbance. The analysis is extended to the bifurcated two-mode steady-state oscillations in the region of parametric excitation. The dependence of the control effectiveness on the system parameters is investigated in the case of the first symmetric mode and the range of oscillation amplitudes in which the proposed control ensures a dissipation of energy is determined. Although control based only on in-plane response quantities is effective in reducing oscillations with a prevailing in-plane component, addition of out-of-plane measures has to be considered when the motion is characterized by two comparable components.

Perpendicular ion heating by velocity-shear-driven waves

Abstract: Perpendicular ion heating resulting from velocity-shear-driven ion-cyclotron waves has been measured for the first time. The experiment was performed in the Naval Research Laboratory's Space Physics Simulation Chamber (SPSC) under plasma conditions approaching those in the natural space environment. Sheared cross-field flow is induced by a controllable, inhomogeneous, transverse, DC electric field (LE ∼ (1–2)ρi) created without drawing significant levels of magnetic-field aligned current. Mode frequency data suggest that the most efficient heating occurs when the Doppler shifted frequency in the ion frame is located near a harmonic of the ion-cyclotron frequency.

Tufting machine with self-aligning gauging modules

Abstract: Symmetrical, modular blocks each having a plurality of fixed, equally spaced, gauging elements, namely loopers, needles, and reeds protruding therefrom, the blocks are positioned on the sides of the guide bars of a tufting machine, each guide bar having transverse channels at equally spaced intervals. These channels respectively receive guide bars of the blocks when the blocks are removably positioned on the sides of the guide bar. Bolts or screws secure the blocks in place on their guide bars so that their needles, loopers, and reeds are appropriately gauged and positioned for tufting action, protruding toward the tufting zone.

Transverse radial expansion and directed flow

Abstract: The effects of an interplay of radial expansion of the thermalized system created in a heavy ion collision and directed flow are discussed. It is shown that the study of azimuthal anisotropy of particle distribution as a function of rapidity and transverse momentum could reveal important information on both radial and directed flow.

The role of tank-treading motions in the transverse migration of a spheroidal vesicle in a shear flow

Abstract: The behaviour of a spheroidal vesicle, in a plane shear flow bounded from one side by a wall, is analysed when the distance from the wall is much larger than the spheroid radius. It is found that tank-treading motions produce a transverse drift away from the wall, proportional to the spheroid eccentricity and the inverse square of the distance from the wall. This drift is independent of inertia, and is completely determined by the characteristics of the vesicle membrane. The relative strength of the contribution to drift from tank-treading motions and from the presence of inertial corrections, is discussed.

Response and Failure of Ductile Circular Plates Struck by a Mass

Abstract: A theoretical analysis is presented in this paper to predict the dynamic plastic response of aluminium alloy and mild steel circular plates when struck normally by blunt solid cylindrical masses at the center Reasonable agreement is obtained with experimental results for the permanent transverse displacements Different failure mechanisms, which have been found in previous experimental studies on aluminium alloy and mild steel plates, are also illustrated by the proposed theory

Single spin asymmetry in inclusive pion production, Collins effect and the string model

Abstract: We calculated the single spin asymmetry in the inclusive pion production in the fragmentation region of transversely polarized proton-proton collisions. We generated the asymmetry at the level of fragmentation function (Collins effect) by the Lund coloured string mechanism. We compared our results to the presently available experimental data. We obtained a qualitative agreement with the data after assuming that the transverse polarizations of the u and the d quarks in the proton are +1 and − 1, respectively, at xB=1.