the produced electric and magnetic fields due to lightning strikes to mountainous ground are determined in this paper. for the sake of simplicity a cone-shaped ground with finite conductivity is assumed to represent a natural nonflat ground. by this assumption, we deal with an axillary symmetrical structure so we use the cylindrical 2d-fdtd to save the simulation memory and time, dramatically. ...

In this paper, we study 2D cylindrical Positron Emission Tomography (2D PET) sampling. We show that rectangular sampling schemes are more efficient than usual square schemes. 1. PET and sampling 1.1 PET The aim of Positron Emission Tomography (PET) is to map the internal nuclear activity of a patient from exterior measurement. Usually, the patient received some nuclear substance by inhalation o...

A linear stability analysis of the Rayleigh–Taylor instability RTI between two ideal inviscid immiscible compressible fluids in cylindrical geometry is performed. Three-dimensional 3D cylindrical as well as two-dimensional 2D axisymmetric and circular unperturbed interfaces are considered and compared to the Cartesian cases with planar interface. Focuses are on the effects of compressibility, g...

| Perfectly Matched Layers (PML) are derived for cylindrical and spherical FDTD grids. The formulation relies on the complex coordinate stretching approach. 2D cylindrical and 3D spherical staggered-grid FDTD codes are written based on the time-domain versions of the equations. Numerical simulations validate the formulation by showing very good agreement between the PML-FDTD results and the fre...

A generalized-Laguerre-Hermite pseudospectral method is proposed for computing symmetric and central vortex states in Bose-Einstein condensates (BECs) in three dimensions with cylindrical symmetry. The new method is based on the properly scaled generalized-Laguerre & Hermite functions and a normalized gradient flow. It enjoys three important advantages: (i) it reduces a three dimensional (3D) p...

Cylindrical surfaces of many irregularities populate aerospace and automotive engine components. Many of these surfaces represent power transmitting shafts and rotary mating parts that require structured meshes to expedite contact and other finite element analyses with their mates. This poses a challenge to surface and volume mesh generators. In this paper a novel method of multiblocking based ...

We present a new discretization for 2D Lagrangian hydrodynamics in rz geometry (cylindrical coordinates), which is total energy conserving and symmetry preserving.

in the present study, vibration of cylindrical laminates with different layers and angles were studied. in order to actuate and polarize in radial direction, a piezoelectric layer was located at outer surface of composite shell. laminates were assumed long enough so that plane strain state analysis in 2d can be used properly. in order to satisfy the boundary conditions, variables in terms of fo...

In the present study, vibration of cylindrical laminates with different layers and angles were studied. In order to actuate and polarize in radial direction, a piezoelectric layer was located at outer surface of composite shell. Laminates were assumed long enough so that plane strain state analysis in 2D can be used properly. In order to satisfy the boundary conditions, variables in terms of Fo...

The vertical mode expansion method (VMEM) [J. Opt. Soc. Am. A31, 293 (2014)] is a frequency-domain numerical method for solving Maxwell's equations in structures that are layered separately in a cylindrical region and its exterior. Based on expanding the electromagnetic field in one-dimensional vertical modes, the VMEM reduces the original three-dimensional problem to a two-dimensional (2D) pro...