Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 21 for “"axisymmetry"”.
-
Circumstellar Distribution of Dust Grains Around Proto -Planetary Nebulae: Observational Evidence for Axisymmetry and 2.5-D Radiative Transfer Model Calculations
… optical. In these imaging surveys, a prevalent axisymmetry has been found to reveal the equatorially-enhanced (toroidal) structure of the PPN shells. Moreover, two morphological types (SOLE-toroidal and DUPLEX-core/elliptical PPNs) have been discovered among PPNs in each survey, which strongly …
-
Semi-Analytical Model to Study Vibrations of High-Speed, Rotating Axisymmetric Bodies Coupled to Other Rotating/ Stationary Structures
… compliant, rotating bodies. Exploiting the axisymmetry of the rotating body, the developed semi-analytical model only discretizes the two-dimensional radial cross-section; Fourier series are used in the circumferential direction. The corresponding formulation for thin-walled, axisymmetric …
-
Critical Phenomena in Gravitational Collapses of Neutron Star Systems
… The code we constructed, GRAstro-2D, assumed axisymmetry to achieve high enough resolution needed for the study.
-
Optimizing GPU Performance in Cylindrical FDTD Simulations
… approximation (ODA), and zoned discrete axisymmetry (ZDA), each balancing accuracy and efficiency for different metasurface geometries. In this thesis, we focus on ZDA, a method tailored for metasurfaces with rotational symmetry. By expressing electromagnetic fields as a sum of angular …
-
Geometrically Nonlinear Analysis of Axially Symmetric, Composite Pressure Domes Using the Method of Multiple Shooting
… is limited in the analysis by the assumptions of axisymmetry and constant thickness. The shell is allowed to have general composite laminate construction, elastic supports at the edges and internal ring stiffeners. In addition, the analysis allows for the possibility of circumferential line loads …
-
Extension of gyrokinetics to transport time scales
… to evolve radial profiles. In tokamaks, due to axisymmetry, the evolution of the axisymmetric radial electric field is a challenging problem requiring substantial modifications to gyrokinetic treatments. The radial electric field, closely related to plasma flow, is known to have a considerable …
-
The performance of high speed reciprocating polymer seals in water
… polymeric ring has been simplified due to its axisymmetry, and modelled in cross section as an elastic beam resting on a spring base, while the deformation of the o-ring has been considered independently since the moduli of the two materials differs by nearly two orders of magnitude. The o-ring …
-
Natural convection of molten salt in laterally heated and top cooled vertical cylinders
… state cases. Results show a departure from axisymmetry for higher aspect ratios in the steady cases. For the cases where the flow becomes unsteady, the nature of the flow is characterized by using Fast Fourier Transform on the time evolution of axial velocity. Temporal variation of the …
-
Development of a Fast X-ray Line Detector System for Two-Phase Flow Measurement
… X-ray source and detector pixels. By assuming axisymmetry, an algorithm has been developed to convert void fraction distribution along the detector pixels to the radial void profile in a circular pipe. The X-ray spectral analysis yielded a novel prediction model for non-chromatic X-rays and …
-
Equilibria and oscillations of magnetised neutron stars
… to rigid-body<br/>free precession.<br/><br/>In axisymmetry, the equations of magnetohydrodynamics reduce to a purely<br/>toroidal-field case and a mixed-field case (with a purely poloidal-field limit). We<br/>solve these equations using a nonlinear code which finds stationary rotating …
-
Experimental investigation of the trigger problem in magnetic reconnection
… current channel and a global mode, which breaks axisymmetry. We model the onset using an empirical Ohm's law and current continuity, which is maintained by ion polarization currents associated with the mode. The model reproduces the exponential growth of the reconnection electric field, and the …
-
Spontaneous tropical cyclogenesis in a cloud revolving numerical model
… this study focuses on one. Using assumptions of axisymmetry for the growing disturbance and focusing on the large scale processes, fields were created for a number of thermodynamic variables along constant height surfaces and as azimuthal means plotted against height. The tropical cyclone is …
-
Tropical cyclone size in observations and in radiative-convective equilibrium
… confirming the relevant length scale obtained in axisymmetry. Ultimately, the results of the equilibrium storm analysis are insufficient to explain the observed distribution of tropical cyclone size, but they provide the first steps toward a more fundamental understanding of the dynamics of size.
-
Zonally symmetric monsoon dynamics in a general circulation model
… land surface. The dynamical constraints of axisymmetry prevent low-level cross-equatorial flow and inhibit the northward transport of moisture onto the continent when there is no temperature gradient across the equator. The ocean cannot supply adequate moisture to feed the monsoon, and the …
-
A Three-dimensional Model of Poroviscous Aquifer Deformation
… irrotational deformation and mechanical axisymmetry, which are more suitable for field applications. Incremental forms of the governing equations are also provided.
-
Study of High Harmonic Fast Waves Interactions in the Scrape off Layer of NSTX-U
… approach in the Petra-M workbench assuming axisymmetry. A 2D density profile is then obtained from a prescribed outer midplane radial profile assuming pressure is uniform on a flux surface. This approach results in density and temperature profiles in which the strong asymmetric nature of …
-
A dynamo case study of Mercury, and the early orbital and thermal evolution of the Moon
… characterized by its weak strength, spin-aligned axisymmetry and a large offset of the magnetic equator relative to Mercury's geographic equator. The combination of these features is difficult to be explained with an Earth-like dynamo. We enhance the traditional dynamo model by adding a stably …
-
Design and analysis of a composite wire-socket attachment
… and one-dimensional models, that utilize axisymmetry, are evaluated. The results of the numerical analysis are used to demonstrate the improvement as a result of a change in material choice or design of the anchor. It is shown that the modification of the load transfer medium results in a …
-
From Spheres to Sheets: Colloidal Hydrodynamics, Thermodynamics, and Statistical Inference
… curvature is increased, it is found that axisymmetry is broken. The constrained normal modes of the sheets are also computed and shed light on the behavior of fluctuations. Additionally, we perform numerical simulations of "tethered" semiflexible sheets with hydrodynamic interactions in …
-
The response of partially-confined right-circular cylinders to internal blast loading
… in section, the simulations are performed in 2D axisymmetry to reduce computational expense. The maximum cylinder deflections and selected final profiles, as well as the impulses imparted to the pendulum, are compared to the corresponding experimental results. With the exception of the 0.75 l …
Page 1 of 2