Showing papers on "Transverse plane published in 2008"
TL;DR: This paper extends NSCBC to account for convection and pressure gradients in boundary planes, resulting in a 3D-NSCBC approach that brings a drastic reduction of flow distortion and numerical reflection, even in regions of strong transverse convection.
263 citations
TL;DR: An information theoretical comparison in photon limited systems shows that the DH-PSF delivers higher Fisher information for 3D localization than the standard PSF, and therefore, DH- PSF systems provide better position estimation accuracy.
Abstract: We demonstrate three-dimensional tracking of fluorescent microparticles, with a computational optical system whose point spread function (PSF) has been engineered to have two twisting lobes along the optical axis, generating a three-dimensional (3D) double-helix (DH) PSF. An information theoretical comparison in photon limited systems shows that the DH-PSF delivers higher Fisher information for 3D localization than the standard PSF. Hence, DH-PSF systems provide better position estimation accuracy. Experiments demonstrate average position estimation accuracies under 14nm and 37nm in the transverse and axial dimensions respectively. The system determines the 3D position of multiple particles with a single image and tracks them over time while providing their velocities.
218 citations
TL;DR: In this article, a C0 finite element formulation is used to carry out free vibration analysis of curved panels using a higher-order formulation, which includes Sanders' approximation for doubly curved shells considering the effects of rotary inertia and transverse shear.
198 citations
TL;DR: In this article, the von Karman nonlinearity and the Casimir force were used to develop reduced-order models for prestressed clamped rectangular and circular electrostatically actuated microplates.
163 citations
Patent•
18 Jul 2008TL;DR: In this article, the electromagnetic field propagates in a dielectric-filled transverse electromagnetic waveguide, and at least one slice of an electro-optic material is disposed in the DME for modulation by the incident electromagnetic field.
Abstract: A method of and apparatus for modulating an optical carrier by an incident electromagnetic field. The electromagnetic field propagates in a dielectric-filled transverse electromagnetic waveguide, At least one slice of an electro-optic material is disposed in the dielectric-filled transverse electromagnetic waveguide, the electro-optic material in the dielectric-filled transverse electromagnetic waveguide having at least one optical waveguide therein which has at least a major portion thereof guiding light in a direction orthogonal with respect to a direction in which the dielectric-filled transverse electromagnetic waveguide guides the incident electromagnetic field. Light is caused to propagate in the at least one optical waveguide in the at least one slice of an electro-optic material in the dielectric-filled transverse electromagnetic waveguide for modulation by the incident electromagnetic field.
160 citations
TL;DR: In this article, the authors studied the time evolution of an energetic current propagating through a finite temperature, strongly coupled, = 4 SYM plasma and proposed a physical picture for their results.
Abstract: Within the framework of the AdS/CFT correspondence, we study the time evolution of an energetic -current propagating through a finite temperature, strongly coupled, = 4 SYM plasma and propose a physical picture for our results. In this picture, the current splits into a pair of massless partons, which then evolve via successive branchings, in such a way that energy is quasi-democratically divided among the products of a branching. We point out a duality between the transverse size of the partonic system produced through branching and the radial distance traveled by the dual Maxwell wave in the AdS geometry. For a time-like current, the branching occurs already in the vacuum, where it gives rise to a system of low-momentum partons isotropically distributed in the transverse plane. But at finite temperature, the branching mechanism is modified by the medium, in that the rate for parton splitting is enhanced by the transfer of transverse momentum from the partons to the plasma. This mechanism, which controls the parton energy loss, is sensitive to the energy density in the plasma, but not to the details of the thermal state. We compute the lifetime of the current for various kinematical regimes and provide physical interpretations for other, related, quantities, so like the meson screening length, the drag force, or the trailing string, that were previously computed via AdS/CFT techniques.
155 citations
TL;DR: In this article, the influence of important test conditions, such as temperature, anisotropy, and precompression was experimentally determined for shear deformation, and the results measured at room temperature showed a stiffer response than those measured at body temperature.
Abstract: To understand brain injuries better, the mechanical properties of brain tissue have been studied for 50 years; however, no universally accepted data set exists. The variation in material properties reported may be caused by differences in testing methods and protocols used. An overview of studies on the mechanical properties of brain tissue is given, focusing on testing methods. Moreover, the influence of important test conditions, such as temperature, anisotropy, and precompression was experimentally determined for shear deformation. The results measured at room temperature show a stiffer response than those measured at body temperature. By applying the time-temperature superposition, a horizontal shift factor a T =8.5-11 was found, which is in agreement with the values found in literature. Anisotropy of samples from the corona radiata was investigated by measuring the shear resistance for different directions in the sagittal, the coronal, and the transverse plane. The results measured in the coronal and the transverse plane were 1.3 and 1.25 times stiffer than the results obtained from the sagittal plane. The variation caused by anisotropy within the same plane of individual samples was found to range from 25% to 54%. The effect of precompression on shear results was investigated and was found to stiffen the sample response. Combinations of these and other factors (postmortem time, donor age, donor type, etc.) lead to large differences among different studies, depending on the different test conditions.
154 citations
TL;DR: In this article, the authors considered transverse oscillations of coronal loops that have both variable circular cross-sectional area and plasma density in the longitudinal direction and derived a second-order ordinary differential equation describing the displacement of the loop axis.
Abstract: We consider transverse oscillations of coronal loops that have both variable circular cross-sectional area and plasma density in the longitudinal direction. The primary focus of this paper is to study the eigenmodes of these oscillations. Implementing the method of asymptotic expansions with the ratio of the loop radius to length as a small parameter, a second-order ordinary differential equation is derived describing the displacement of the loop axis. Together with the boundary conditions at the tube ends that follow from the frozen-in condition, this equation constitutes the Sturm-Liouville problem determining the eigenfrequencies and eigenmodes. Our results are relevant to the magnetoseismological method of estimating the coronal density scale height by using the observed ratio of the fundamental frequency and first overtone of loop kink oscillations. It is shown that this method is very sensitive to the tube expansion factor, which is the ratio of the tube radii at the apex and footpoints. The estimated scale height is a monotonically decreasing function of the expansion factor.
120 citations
TL;DR: This is the first study to quantitatively describe the angular location of the radial tuberosity and the relationship of the distal biceps tendon on the tuberosity.
107 citations
TL;DR: In this paper, the authors studied the excitation and damping of transverse oscillations in a multistranded model of a straight line-tied coronal loop and found that at any location in the structure, two dominant frequencies are found: the frequency of the global mode or quasi-mode, and the local Alfv?n frequency.
Abstract: We study the excitation and damping of transverse oscillations in a multistranded model of a straight line-tied coronal loop. The transverse geometry of our equilibrium configuration is quite irregular and more realistic than the usual cylindrical loop model. By numerically solving the time-dependent ideal magnetohydrodynamic equations in two dimensions, we show how the global motion of the whole bundle of strands, excited by an external disturbance, is converted into localized Alfv?nic motions due to the process of resonant absorption. This process produces the attenuation of the transverse oscillations. At any location in the structure, two dominant frequencies are found: the frequency of the global mode or quasi-mode, and the local Alfv?n frequency. We find that the mechanism of mode conversion, due to the coupling between fast and Alfv?n waves, is not compromised by the complicated geometry of the model. We also show that it is possible to have energy conversion not only at the external edge of the composite loop, but also inside the structure. The implications of these results and their relationship with the observations are discussed.
105 citations
TL;DR: In this article, the authors utilized chromospheric observations obtained at MLSO of the 2006 December 6 Moreton wave and subsequent filament activation to conduct a comprehensive analysis of the wave-filament interaction.
Abstract: We utilize chromospheric observations obtained at MLSO of the 2006 December 6 Moreton wave, which exhibits two distinct fronts, and subsequent filament activation to conduct a comprehensive analysis of the wave-filament interaction. By determining the period, amplitude, and evolution of the oscillations in the activated filament, we make certain inferences regarding the physical properties of both the wave and the filament. The large-amplitude oscillations induced in the filament by the wave passage last on the order of 180 minutes and demonstrate a complicated mixture of transverse and perpendicular motion with respect to the filament spine. These oscillations are predominantly along the filament axis, with a period of ~29 minutes and maximum line-of-sight velocity amplitude of ~41 km s−1. A careful examination of the complex oscillatory response of the filament elucidates some of the fundamental characteristics of the related Moreton wave. Specifically, we infer the maximum total kinetic energy involved in the interaction, the structure and topology of the passing wave, and discuss implications for the topology of the responding magnetic structure supporting the filament. The results of this observational study equip us with a better understanding of how filaments become activated and the nature of their responses to large propagating disturbances.
TL;DR: In this paper, the authors studied the excitation and damping of transverse oscillations in a multi-stranded model of a straight line-tied coronal loop, and they found that the mechanism of mode conversion, due to the coupling between fast and Alfv\'en waves, is not compromised by the complicated geometry of the model.
Abstract: We study the excitation and damping of transverse oscillations in a multi-stranded model of a straight line-tied coronal loop. The transverse geometry of our equilibrium configuration is quite irregular and more realistic than the usual cylindrical loop model. By numerically solving the time-dependent ideal magnetohydrodynamic equations in two dimensions we show how the global motion of the whole bundle of strands, excited by an external disturbance, is converted into localized Alfv\'enic motions due to the process of resonant absorption. This process produces the attenuation of the transverse oscillations. At any location in the structure two dominant frequencies are found, the frequency of the global mode, or quasi-mode, and the local Alfv\'en frequency. We find that the mechanism of mode conversion, due to the coupling between fast and Alfv\'en waves, is not compromised by the complicated geometry of the model. We also show that it is possible to have energy conversion not only at the external edge of the composite loop but also inside the structure. The implications of these results and their relationship with the observations are discussed.
TL;DR: In this paper, the authors investigated the propagation of transverse domain walls in magnetic nanowires under axial and transverse magnetic fields using three-dimensional micromagnetic modeling.
Abstract: We have investigated the propagation of transverse domain walls in magnetic nanowires under axial and transverse magnetic fields using three-dimensional micromagnetic modeling. Transverse magnetic fields change the domain wall width and, below the Walker field, either increase or decrease the domain wall velocity depending when the field and wall magnetization are parallel or antiparallel, respectively. Furthermore, differences in the Walker field also appear for opposite transverse fields, and a surprising result is that under relatively high axial and transverse fields, Walker breakdown can be completely suppressed and the domain wall velocity returns to several hundreds of ms−1.
TL;DR: In this paper, the authors present results of numerical simulations studying the evolution of a localised transverse magneto-hydrodynamic wave in a uniform magnetic field, and conclude that the CoMP results provide an independent seismological proof that the corona is structured in density in the perpendicular direction.
Abstract: The peculiarities of the propagating transverse waves observed in the solar corona with the Coronal Multi-channel Polarimeter (CoMP) indicate the existence of fine field structuring in the coronal density. We present results of numerical simulations studying the evolution of a localised transverse magneto-hydrodynamic wave in a uniform magnetic field. We consider two initial low plasma-beta equilibria: one with a homogeneous density, and one with a field-aligned dense structure (such as a loop or a plume). The perpendicular localisation of the wave strongly determines the angular distribution of the energy propagation. If the perpendicular scale of the wave is significantly smaller than the parallel scale (e.g. wavelength), as established by CoMP, the wave develops as an oblique fast magneto-acoustic wave. In an unstructured medium, the energy of such a wave is transferred mainly across the magnetic field. However, it is possible to channel the energy of the transverse wave along the magnetic field in the presence of a field-aligned density enhancement. We conclude that the CoMP results provide an independent seismological proof that the corona is structured in density in the perpendicular direction.
TL;DR: In this paper, the vortex-induced vibrations of an elastically mounted rigid cylinder able to move in line and transverse to the flow, with equal mass ratio and natural frequencies in both directions, were studied.
TL;DR: In this paper, an improved higher order zigzag theory is presented and applied to study the buckling of laminated sandwich plates, which satisfies the conditions of transverse shear stress continuity at all the layer interfaces.
Abstract: An improved higher order zigzag theory is presented and it is applied to study the buckling of laminated sandwich plates The present theory satisfies the conditions of transverse shear stress continuity at all the layer interfaces including transverse shear stress free conditions at the top and bottom surfaces of the plate The variation of in-plane displacements through thickness direction is assumed to be cubic for both the face sheets and the core, while transverse displacement is assumed to vary quadratically within the core but it remains constant over the face sheets The core is modeled as a three-dimensional elastic continuum An efficient C 0 finite element is proposed for the implementation of the improved plate theory The accuracy and range of applicability of the present formulation are established by comparing the present results with 3D elasticity solutions and other results available in literature
TL;DR: In this paper, the authors present a model to predict the longitudinal and two orthogonal transverse strain components from measured wavelength shifts of the Bragg peaks observed in combined loading tests.
Abstract: The principle of operation of a multi-parameter dual Bragg grating fiber optic sensor formed in a polarization maintaining fiber is described. The response of the sensor to separately applied longitudinal loading, transverse loading and temperature change is presented in terms of wavelength shifts of the Bragg peaks. Results of those tests are used as sensor calibration data. A model to predict the longitudinal and two orthogonal transverse strain components from measured wavelength shifts of the Bragg peaks observed in combined loading tests is described. The model is based on an assumed linear behavior between wavelength shifts and sensor loadings and uses the calibration data as input. Predictions of transverse strain are compared with applied strains in the combined loading tests and found to be inadequate for transverse strain components. A model for predicting strains is then developed to account for non-linearities between transverse loading and wavelength shifts observed in sensor calibration data. Predictions of longitudinal strain and both transverse strain components from measured wavelength shifts in combined loading are seen to be in excellent agreement with applied test strains.
04 May 2008
TL;DR: In this article, the absolute emission rate of photon pairs produced in SPDC when all interacting fields are in a single transverse Gaussian mode was derived. But the exact emission rate was not analyzed.
Abstract: We provide expressions for the absolute emission rate of photon pairs produced in SPDC when all interacting fields are in a single transverse Gaussian mode.
TL;DR: In this article, the transverse modulus of three high modulus (M40, M46 and K63712) carbon fibres has first been measured directly by nano-indentation measurements.
Abstract: In this study the transverse modulus of three high modulus (M40, M46 and K63712) carbon fibres has first been measured directly by nano-indentation measurements. Transverse tensile tests on unidirectional epoxy composites were then performed, and the comparison was made between transverse fibre properties from indentation and those needed to obtain the measured transverse composite modulus using micromechanics expressions. The latter tended to underestimate values from indentation, by up to 36%, and reasons for this are discussed. Values of transverse fibre modulus determined by both methods decrease as longitudinal fibre modulus increases.
TL;DR: In this article, the forced transverse vibrations of an elastically connected simply supported double-beam system under compressive axial load were investigated under the assumption that the two beams of the system are continuously joined by a Winkler elastic layer.
TL;DR: It is shown that an EIT medium near the interface between a dielectric and a negative-index metamaterial can establish tight longitudinal and transverse confinement plus extreme slowing of surface polaritons, in both transverse electric andTransverse magnetic polarizations, while simultaneously avoiding losses.
Abstract: We propose fast all-optical control of surface polaritons by placing an electromagnetically induced transparency (EIT) medium at an interface between two materials. EIT provides longitudinal compression and a slow group velocity, while matching properties of the two materials at the interface provides strong transverse confinement. In particular, we show that an EIT medium near the interface between a dielectric and a negative-index metamaterial can establish tight longitudinal and transverse confinement plus extreme slowing of surface polaritons, in both transverse electric and transverse magnetic polarizations, while simultaneously avoiding losses.
TL;DR: In this paper, the authors developed an analytical approximation that describes the shift in P1/2P2 in terms of the ratio L/Λc of the length 2L of a coronal loop and the density scale height Λc.
Abstract: Context. In transverse coronal loop oscillations, two periodicities have been measured simultaneously and are interpreted as the fundamental kink mode (with period P1) and the first harmonic (with period P2). Deviations of the period ratio P1/2P2 from unity provide information about the extent of longitudinal structuring within the loop. Aims. Here we develop an analytical approximation that describes the shift in P1/2P2 in terms of the ratio L/Λc of the length 2L of a coronal loop and the density scale height Λc. Methods. We study the MHD wave equations in a low β plasma using the thin tube approximation. Disturbances are described by a differential equation which may be solved for various equilibrium density profiles, obtaining dispersion relations in terms of Bessel functions. These dispersion relations may be used to obtain analytical approximations to the periods P1 and P2 .W e also present a variational approach to determining the period ratio and show how the WKB method may be used. Results. Analytical approximations to the period ratio P1/2P2 are used to shed light on the magnitude of longitudinal structuring in a loop, leading to a determination of the density scale height. We apply our formula to the observations in Verwichte et al. (2004) and Van Doorsselaere et al. (2007), obtaining the coronal density scale height. Conclusions. Our simple formula and approximate approaches highlight a useful analytical tool for coronal seismology. We demonstrate that P1/2P2 is linked to the density scale height, with no need for estimates of other external parameters. Given the accuracy of current observations, our formula provides a convenient means of determining density scale heights.
TL;DR: In this article, the collective oscillatory properties of the system due to the interaction between the individual loops are investigated from two points of view: frequency and spatial structure of the normal modes are studied.
Abstract: We study transverse fast magnetohydrodynamic waves in a system of two coronal loops modeled as smoothed, dense plasma cylinders in a uniform magnetic field. The collective oscillatory properties of the system due to the interaction between the individual loops are investigated from two points of view. First, the frequency and spatial structure of the normal modes are studied. The system supports four trapped normal modes in which the loops move rigidly in the transverse direction. The direction of the motions is either parallel or perpendicular to the plane containing the axes of the loops. Two of these modes correspond to oscillations of the loops in phase, while in the other two they move in antiphase. Thus, these solutions are the generalization of the kink mode of a single cylinder to the double cylinder case. Second, we analyze the time-dependent problem of the excitation of the pair of tubes. We find that depending on the shape and location of the initial disturbance, different normal modes can be excited. The frequencies of normal modes are accurately recovered from the numerical simulations. In some cases, because of the simultaneous excitation of several eigenmodes, the system shows beating.
TL;DR: This study provides biomechanical evidence that patients weighing more than 40 to 45 kg who undergo stabilization of a transverse midshaft femur fracture with titanium elastic nails are at risk for loss of reduction in the sagittal and coronal planes.
Abstract: Background Increasing weight in relation to total diameter of implanted titanium elastic nails has been found to be significantly associated with increasing sagittal angulation. However, the biomechanical literature has not well established the load at which failure of titanium elastic nails in the sagittal and coronal planes occurs. The purpose of this study was to determine load to failure in sagittal and coronal plane bending of transverse midshaft femur fractures stabilized with titanium elastic nails and correlate this with the maximum patient weight. Methods Ten synthetic, pediatric-sized femurs 35 cm in length with an intramedullary canal diameter of 9.5 mm were used. Transverse midshaft fracture patterns were created with a handheld saw. Two 4.0-mm titanium elastic nails were then placed in a retrograde fashion through medial and lateral insertion sites in the distal metaphysis of the femur to stabilize the simulated fractures. A 4-point bending load to failure test was performed on each of the femurs. Five femurs were tested in the sagittal plane, and 5 femurs were tested in the coronal plane. Yield load, bending stiffness, and bending moments for both testing configurations were determined. Results For the sagittal plane bending tests, the yield load was 628 +/- 29 N. For the coronal plane bending tests, the yield load was 596 +/- 20 N. The resulting bending moments in the sagittal and coronal planes were 20.4 +/- 0.9 and 19.4 +/- 0.6 Nm, respectively. From these data, we correlated bending moments with in vivo gait data to find a patient weight cutoff of 40 to 45 kg. Clinical relevance With the increasing rate of childhood obesity and tendency for sagittal and coronal angulation of femur fractures treated with titanium elastic nails, it is necessary to determine the load at which permanent sagittal and coronal deformation of the nails occurs because this may result in an unfavorable outcome. Conclusions Our study provides biomechanical evidence that patients weighing more than 40 to 45 kg who undergo stabilization of a transverse midshaft femur fracture with titanium elastic nails are at risk for loss of reduction in the sagittal and coronal planes.
TL;DR: In this article, the angular dependence of the transverse and vortex modes in a magnetic nanotube is investigated as a function of the tube geometry, by means of analytical calculations and numerical simulations.
Abstract: The angular dependence of the transverse and vortex modes in a magnetic nanotube is investigated as a function of the tube geometry, by means of analytical calculations and numerical simulations. A critical radius defining the transition between vortex and transverse reversal modes is determined, leading to low or high coercivity modes just by varying the direction of the external field, in a fixed nanotube.
TL;DR: VCA provided excellent correction of coronal and transverse planes with normalization of thoracic kyphosis in Lenke type 1 adolescent idiopathic scoliosis surgery, and there were no perioperative complications.
Abstract: STUDY DESIGN Prospective multicentric study. OBJECTIVE To present the preliminary results of an innovative method for standardized correction of scoliosis, vertebral coplanar alignment (VCA), based on a novel concept: the relocation of vertebral axis in a single plane. SUMMARY OF BACKGROUND DATA Normal standing spine has no rotation in coronal or transverse planes, therefore X and Z axis of vertebrae are in the same plane: they are coplanar. VCA intends to relocate these axis in one plane, correcting rotation and translation, while X axis are returned to its normal posterior divergence in sagittal plane in thoracic spine. METHODS Twenty-five consecutive adolescent idiopathic scoliosis patients (Lenke type 1) underwent posterior surgery with segmental pedicle screw fixation. Slotted tubes were attached to convex side screws. Two longitudinal rods were inserted through the end of tubes. Then, they were separated along the slots, driving the tubes into one plane, making the axis of the vertebrae coplanar and thus correcting transverse rotation and coronal translation. To obtain kyphosis, distal ends of the tubes were spread in thoracic spine. Correction was maintained by locking a definitive rod in the concave side, then tubes were retrieved and the convex side rod, inserted and tightened. Correction was assessed on preoperative and postoperative full-spine standing radiograph. Vertebral rotation was measured on computed tomography-scan and magnetic resonance imaging. RESULTS Preoperative average thoracic curves of 61 degrees were corrected to 16 degrees (73%). Preoperative average thoracolumbar curves of 39 degrees were corrected to 12 degrees (70%). Preoperative average thoracic apical rotation of 24 degrees was corrected to 11 degrees (56%). Preoperative average thoracic kyphosis of 18 degrees remained unchanged after surgery; however, no patients had kyphosis <10 degrees after surgery. Rib hump improved from 30 to 11 mm (65%). There were no perioperative complications. CONCLUSION VCA provided excellent correction of coronal and transverse planes with normalization of thoracic kyphosis in Lenke type 1 adolescent idiopathic scoliosis surgery.
TL;DR: In this article, the collective plasmonic modes of metal nanoparticles in periodic two-dimensional (2D) arrays within a point-dipole description were investigated, and the dynamic dispersion relations of the 2D arrays were obtained through a method which gave an effective polarizability describing the collective response of a system.
Abstract: We investigate the collective plasmonic modes of metal nanoparticles in periodic two-dimensional (2D) arrays within a point-dipole description. The dynamic dispersion relations of the 2D arrays are obtained through a method which gives an effective polarizability describing the collective response of a system. Both the dispersion relations and mode qualities are simultaneously related to the imaginary part of the effective polarizability, which has contributions from the single-particle response as well as the interparticle coupling. The transverse long-range dipolar interaction is dominated by a wave term together with a purely geometrical constant representing the static geometrical contribution to resonant frequencies. As concrete examples, we considered small Ag spheres arranged in a square lattice. We find that inside the light cone, the transverse quasimode has a reasonably high mode quality, while the two in-plane modes show significant radiation damping. Near the light line, we observe strong coupling with free photons for the bands of the transverse mode and the transverse in-plane mode, and the longitudinal in-plane mode exhibits a negative group velocity inside the light cone. Vanishing group velocities in the light cone for all the quasimodes are found to be intrinsic properties of the 2D metal nanosphere dense arrays.
TL;DR: In this paper, a non-force-free magnetic field is derived from vector magnetograms, where the boundary conditions are at least two layers of vector magnetogram, one at the photospheric level and the other at the chromospheric scale.
Abstract: We develop an approach to deriving the three-dimensional non-force-free coronal magnetic field from vector magnetograms. Based on the principle of minimum dissipation rate, a general non-force-free magnetic field is expressed as the superposition of one potential field and two constant-α (linear) force-free fields. Each is extrapolated from its bottom boundary data, providing the normal component only. The constant-α parameters are distinct and determined by minimizing the deviations between the numerically computed and measured transverse magnetic field at the bottom boundary. The boundary conditions required are at least two layers of vector magnetograms, one at the photospheric level and the other at the chromospheric level, presumably. We apply our approach to a few analytic test cases, especially to two nonlinear force-free cases examined by Schrijver et al. (Solar Phys.235, 161, 2006). We find that for one case with small α parameters, the quantitative measures of the quality of our result are better than the median values of those from a set of nonlinear force-free methods. The reconstructed magnetic-field configuration is valid up to a vertical height of the transverse scale. For the other cases, the results remain valid to a lower vertical height owing to the limitations of the linear force-free-field solver. Because our method is based on the fast-Fourier-transform algorithm, it is much faster and easy to implement. We discuss the potential usefulness of our method and its limitations.
Abstract: Coherent structures and mixing in the flow field of a jet in crossflow have been studied using computational (large eddy simulation) and experimental (particle image velocimetry and laser-induced fluorescence) techniques. The mean scalar fields and turbulence statistics as determined by both are compared for circular, elliptic, and square nozzles. For the latter configurations, effects of orientation are considered. The computations reveal that the distribution of a passive scalar in a cross-sectional plane can be single- or double-peaked, depending on the nozzle shape and orientation. A proper orthogonal decomposition of the transverse velocity indicates that coherent structures may be responsible for this phenomenon. Nozzles which have a single-peaked distribution have stronger modes in transverse direction. The global mixing performance is superior for these nozzle types. This is the case for the blunt square nozzle and for the elliptic nozzle with high aspect ratio. It is further demonstrated that the flow field contains large regions in which a passive scalar is transported up the mean gradient (counter-gradient transport) which implies failure of the gradient diffusion hypothesis.
TL;DR: In this article, the fiber orientation variation in the direction of the loading, and the other one perpendicular to the loading direction, were identified as possible contributors to the buckling load improvements.
Abstract: Analysis of non-traditional Variable Stiffness (VS) laminates, obtained by steering the fiber orientation as a spatial function of location, have shown to improve buckling load carrying capacity of flat rectangular panels under axial compressive loads. In some cases the buckling load of simply supported panels doubled compared to the best conventional laminate with straight fibers. Two distinct cases of stiffness variation, one due to fiber orientation variation in the direction of the loading, and the other one perpendicular to the loading direction, were identified as possible contributors to the buckling load improvements. In the first case, the increase was attributed to the favorable distribution of the transverse in-plane stresses over the panel platform. In the second case, a higher degree of improvement was obtained due to the re-distribution of the applied in-plane loads. Experimental results, however, showed substantially higher levels of buckling load improvements compared with theoretical pred...