scholarly journals Green's function for the Laplace–Beltrami operator on a toroidal surface

Author(s):  
Christopher C. Green ◽  
Jonathan S. Marshall

Green's function for the Laplace–Beltrami operator on the surface of a three-dimensional ring torus is constructed. An integral ingredient of our approach is the stereographic projection of the torus surface onto a planar annulus. Our representation for Green's function is written in terms of the Schottky–Klein prime function associated with the annulus and the dilogarithm function. We also consider an application of our results to vortex dynamics on the surface of a torus.

1967 ◽  
Vol 22 (4) ◽  
pp. 422-431 ◽  
Author(s):  
Kyozaburo Kambe

A general theory of electron diffraction by crystals is developed. The crystals are assumed to be infinitely extended in two dimensions and finite in the third dimension. For the scattering problem by this structure two-dimensionally expanded forms of GREEN’S function and integral equation are at first derived, and combined in single three-dimensional forms. EWALD’S method is applied to sum up the series for GREEN’S function.


2006 ◽  
Vol 324-325 ◽  
pp. 387-390
Author(s):  
Yoon Suk Chang ◽  
Shin Beom Choi ◽  
Jae Boong Choi ◽  
Young Jin Kim ◽  
Myung Jo Jhung ◽  
...  

Major nuclear components have been designed by conservative codes to prevent unanticipated fatigue failure. However, more realistic and effective assessment is necessary in proof of continued operation beyond the design life. In the present paper, three-dimensional stress and fatigue evaluation is carried out for pressurizer employing complex full geometry itself instead of conventional discrete subcomponents. For this purpose, temperature and mechanical stress transfer Green’s functions are derived from finite element analyses and applied to critical locations of pressurizer. In accordance with comparison of resulting stresses obtained from the Green’s function and detailed finite element analysis, suitability of the specific Green’s function is investigated. Finally, prototype of fatigue life assessment results is provided along with relevant ongoing activities.


2017 ◽  
Vol 42 (3) ◽  
pp. 164-176 ◽  
Author(s):  
Joshua Paul Marshall ◽  
Joseph David Richardson ◽  
Carlos Jose Montalvo

There exists many applications for which wind-velocity is desired over a three-dimensional space. The vector field associated with these wind velocities is known as a “windfield” or “velocity-windfield.” The present work provides a fast method to characterize windfields. The approach uses the free-space Green’s function for potential theory as an inexpensive surrogate model in lieu of either complicated physics-based models or other types of surrogate models, both of which require volumetric discretizations for the three-dimensional case. Using the gradient of the third Green’s identity, the wind-velocity in the interior of a domain is entirely characterized by a surface discretization while still providing a three-dimensional model. The unknown densities on the surface are determined from enforcement of the interior form of the identity at arbitrary points coinciding with wind measurements taken by unmanned aerial vehicles. Numerical results support the feasibility of the method.


2004 ◽  
Vol 56 (3) ◽  
pp. 590-611
Author(s):  
Yilong Ni

AbstractWe study the Riemannian Laplace-Beltrami operator L on a Riemannian manifold with Heisenberg group H1 as boundary. We calculate the heat kernel and Green's function for L, and give global and small time estimates of the heat kernel. A class of hypersurfaces in this manifold can be regarded as approximations of H1. We also restrict L to each hypersurface and calculate the corresponding heat kernel and Green's function. We will see that the heat kernel and Green's function converge to the heat kernel and Green's function on the boundary.


1982 ◽  
Vol 1 (18) ◽  
pp. 165 ◽  
Author(s):  
T. Sawaragi ◽  
M. Kubo

In harbors affected by ocean swells,cargo handlings are often interrupted and irooring lines are broken as a result of severe ship motionsl). In order to decrease such accidents, the noored ship notions in a harbor basin must be studied. In this paper the ship notions in the harbor basin are investigated by using three dimensional Green's function and close agreement between theoretical and experimental results can be found. New methods to reduce noored ship motion are also proposed. The efficiency of these methods is verified theoretically and experimentally.


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