A Complex Velocity solution of the flutter equations

A vast amount of observational data concerning the structure and kinematics of the Magellanic Clouds is now available. Many basic quantities (e.g. distances and geometry) are, however, not yet sufficiently well determined. Interactions between the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC) and our Galaxy have dominated the evolution of the Clouds, causing bursts of star formation which, together with stochastic self-propagating star formation, produced the observed structures. In the youngest generation in the LMC it is seen as an intricate pattern imitating a fragmented spiral structure. In the SMC much of the fragmentation is along the line of sight complicating the reconstruction of its history. The violent events in the past are also recognizable in complex velocity patterns which make the analysis of the kinematics of the Clouds difficult.

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Adaptive regridding in 3D reflection tomography

Annals of Geophysics ◽

10.4401/ag-3936 ◽

1997 ◽

Vol 40 (1) ◽

Author(s):

G. Böhm ◽

G. Rossi ◽

A. Vesnaver

Keyword(s):

Velocity Field ◽

A Priori ◽

A Priori Information ◽

Complex Velocity ◽

Variable Resolution ◽

Fitting Procedure ◽

Voronoi Polygons ◽

Fully Automatic ◽

Priori Information ◽

Reflection Tomography

3D reflection tomography allows the macro-model of complex geological structures to be reconstructed. In the usual approach, the spatial distribution of the velocity field is discretized by regular grids. This choice simplifies the development of the related software, but introduces two serious drawbacks: various domains of the model may be poorly covered, and a relevant mismatch between the grid and a complex velocity field may occur. So the tomographic inversion becomes unstable, unreliable and necessarily blurred. In this paper we introduce an algorithm to adapt the grid to the available ray paths and to the velocity field in sequence: so we get irregular grids with a locally variable resolution. We can guide the grid fitting procedure interactively, if we are going to introduce some geological a priori information; otherwise, we define a fully automatic approach, which exploits the Delauny triangles and Voronoi polygons.

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The Two-Phase Hell-Shaw Flow: Construction of an Exact Solution

International Journal of Applied Mechanics and Engineering ◽

10.2478/ijame-2013-0016 ◽

2013 ◽

Vol 18 (1) ◽

pp. 249-257

Author(s):

K.R. Malaikah

Keyword(s):

Exact Solution ◽

Velocity Potential ◽

Time Dependent ◽

Computational Domain ◽

Phase Problem ◽

Complex Velocity ◽

Two Phase ◽

Interface Evolution ◽

Complex Velocity Potential ◽

Branch Cuts

We consider a two-phase Hele-Shaw cell whether or not the gap thickness is time-dependent. We construct an exact solution in terms of the Schwarz function of the interface for the two-phase Hele-Shaw flow. The derivation is based upon the single-valued complex velocity potential instead of the multiple-valued complex potential. As a result, the construction is applicable to the case of the time-dependent gap. In addition, there is no need to introduce branch cuts in the computational domain. Furthermore, the interface evolution in a two-phase problem is closely linked to its counterpart in a one-phase problem

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Are Complex Velocity Models Absolutely Necessary for Microseismic Processing?

Fifth EAGE Passive Seismic Workshop ◽

10.3997/2214-4609.20142172 ◽

2014 ◽

Author(s):

D. Pandolfi ◽

E. Rebel-Schisselé ◽

E. Auger ◽

T. Bardainne

Keyword(s):

Complex Velocity ◽

Velocity Models

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Complex Velocity Model Reconstruction on the Base of Seismic Tomography and Kinematic Migration

Saint Petersburg 2008 ◽

10.3997/2214-4609.20146820 ◽

2008 ◽

Author(s):

YU.V. Roslov ◽

A.A. Vinnik ◽

A.V. Kopylova ◽

N.N. Efimova

Keyword(s):

Seismic Tomography ◽

Velocity Model ◽

Model Reconstruction ◽

Complex Velocity ◽

Complex Velocity Model

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Reconstructing the Scene: New Views of Supernovae and Progenitors from the SNSPOL Project

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317003052 ◽

2016 ◽

Vol 12 (S329) ◽

pp. 54-58

Author(s):

Jennifer L. Hoffman ◽

G. Grant Williams ◽

Douglas C. Leonard ◽

Christopher Bilinski ◽

Luc Dessart ◽

...

Keyword(s):

Radiative Transfer ◽

Electron Scattering ◽

Time Dependent ◽

Complex Velocity ◽

Circumstellar Material ◽

Radiative Transfer Models ◽

The Future ◽

Geometrical Information ◽

Physical Phenomena ◽

Over Time

AbstractBecause polarization encodes geometrical information about unresolved scattering regions, it provides a unique tool for analyzing the 3-D structures of supernovae (SNe) and their surroundings. SNe of all types exhibit time-dependent spectropolarimetric signatures produced primarily by electron scattering. These signatures reveal physical phenomena such as complex velocity structures, changing illumination patterns, and asymmetric morphologies within the ejecta and surrounding material. Interpreting changes in polarization over time yields unprecedentedly detailed information about supernovae, their progenitors, and their evolution.Begun in 2012, the SNSPOL Project continues to amass the largest database of time-dependent spectropolarimetric data on SNe. I present an overview of the project and its recent results. In the future, combining such data with interpretive radiative transfer models will further constrain explosion mechanisms and processes that shape SN ejecta, uncover new relationships among SN types, and probe the properties of progenitor winds and circumstellar material.

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