Transverse plane

About: Transverse plane is a research topic. Over the lifetime, 17069 publications have been published within this topic receiving 194059 citations. The topic is also known as: axial plane.

Mixing in Circular and Non-circular Jets in Crossflow

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.

First observation of a transverse vertical oscillation during the formation of a hot post-flare loop

Abstract: Aims. We report and analyse the first observation of a transverse oscillation in a hot coronal loop with the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO), following a linked coronal-flare mass-ejection event on the 3 November 2010. The oscillating coronal loop is observed off the east solar limb and exclusively in the 131 A and 94 A bandpasses, indicating a loop plasma of temperature in the range of 9-11 MK. Furthermore, the loop is not observed to cool into the other AIA channels, but just disappears from all bandpasses at the end of the oscillation. Methods. A time series analysis of the loop oscillation is conducted by taking several cuts at different positions along the loop, estimating the transverse displacements over time for two strands in the loop and fitting those with a damped cosine curve. Intensity time variations, both along the loop and for a series of cut cross-sections, are investigated. Using a three-dimensional loop geometry obtained from a comparison of STEREO-B/EUVI and AIA images, we model different modes of transverse oscillations in the uniformly filled loop. Results. Our time series analysis reveals a period of 302 ± 14 s (291 ± 9 s) and a damping time of 306 ± 43 s (487 ± 125 s) for the first (second) loop strand. A spatial phase shift along the loop of approximately 180° suggests that we observe a higher order harmonic. Intensity oscillations are consistent with an interpretation in terms of a vertically polarised mode. Our forward modelling suggests that the loop oscillates as either a second or third order harmonic of this mode. Conclusions. This is the first observation of a transverse loop oscillation observed exclusively in the hot coronal lines. The loop oscillation is vertically polarised and is dominated by a higher order harmonic mode. We conclude that the excitation mechanism of this 5 min period oscillation is directly connected with the reconnection processes that form the post flare loop, which differs from the blast wave excitation mechanism often proposed as the cause of cooler transverse loop oscillations. © 2012 ESO.

Unidirectional fiber–polymer composites: Swelling and modulus anisotropy

Abstract: The solvent swelling of unidirectional rubber–fiber composites was studied. The amount of matrix swelling was constrained to the extent that would be predicted from the thermodynamic theories of elasticity and polymer–solvent interaction. The geometry of swelling was found to be orthotropic in nature. A simple trigonometric function was derived to relate linear deformation due to swelling to the angle which the direction of its measurement makes with the fiber direction. The validity of the derivation was demonstrated experimentally. Considering swelling to be the imposition of tensile forces of equal magnitude in all directions, and considering a swelling-induced linear deformation to be analogous to a tensile compliance, a simple set of relationships between elastic parameters and their direction of measurement was derived: where Eθ, Gθ, vθ, and ηθ are Young's modulus, shear modulus, Poisson's ratio, and the shear coupling ratio measured in a longitudinal transverse plane at an angle with the fiber direction, respectively, and EL, GLT, and θLT are the longitudinal Young's modulus, the longitudinal transverse shear modulus, and the longitudinal transverse Poisson ratio, respectively. Further simplifying the case of combined transverse isotropy and special orthotropy was the conclusion that 1/GLT = 1/ET + (1 + 2vLT)/EL. The relationships for G and E were experimentally demonstrated.

Equivalent boundary conditions for thin orthotropic layer between two solids: reflection, refraction, and interface waves.

Abstract: Boundary conditions for an interface between two solids are introduced to model a thin orthotropic interface layer. The plane of symmetry of the layer material coincides with the incidence plane. Boundary conditions relating stresses and displacements on both sides of the interface are obtained from an asymptotic representation of the three‐dimensional solutions for an interface layer whose thickness is small compared to the wavelength. The results for anisotropic boundary conditions are a generalization of our previous results [S. I. Rokhlin and Y. J. Wang, J. Acoust. Soc. Am. 89, 505–515 (1991)] for an isotropic viscoelastic layer. The interface boundary conditions obtained contain interface stiffness and inertia and terms involving coupling between normal and tangential stresses and displacements. The applicability of such boundary conditions is analyzed by comparison with exact solutions for reflection. As in the isotropic case, fundamental boundary‐layer conditions are introduced containing only one transverse or normal mass or stiffness. It is shown that the solution for more accurate interface boundary conditions, which include two inertia elements and two stiffness elements, can be decomposed into a sum of fundamental solutions. Interface waves along such an interface are considered. Characteristic equations for these waves are obtained in closed form for different types of approximate boundary conditions and the velocities calculated from them are compared to the exact solution. It is shown that retention of the terms describing coupling between normal and transverse stresses and displacements is essential for calculating the velocity of an antisymmetric interface wave.