A cylindrical wave expansion method is developed to obtain the scattering field for an ideal
two-dimensional cylindrical invisibility cloak. A near-ideal model of the invisibility cloak is set up
to solve the boundary problem at the inner boundary of the cloak shell. We confirm that a cloak
with the ideal material parameters is a perfect invisibility cloak by systematically studying the
change of the scattering coefficients from the near-ideal case to the ideal one. However, due to the
slow convergence of the zeroth order scattering coefficients, a tiny perturbation on the cloak would
induce a noticeable field scattering and penetration.
In an electromagnetic cloak based on a transformation approach, reduced sets of
material properties are generally favored due to their easier implementation in reality,
although a seemingly inevitable drawback of undesired reflection exists in such cloaks.
Here we suggest using high-order transformations to create smooth moduli at the outer
boundary of the cloak, therefore completely eliminating the detrimental scattering
within the limit of geometric optics. We apply this scheme to a non-magnetic
cylindrical cloak and demonstrate that the scattered field is reduced substantially in a
cloak with optimal quadratic transformation as compared to its linear counterpart.
We obtained the energy transport velocity distribution for a three dimensional ideal cloak
explicitly. Near the operation frequency, the energy transport velocity has rather peculiar
distribution. The velocity along a line joining the origin of the cloak is a constant, while
the velocity approaches zero at the inner boundary of the cloak. A ray pointing right into
the origin of the cloak will experience abrupt changes of velocities when it impinges on the
inner surface of the cloak. This peculiar distribution causes long time delays for beams
passing through the ideal cloak within a geometric optics description.
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3 simple AVR assembler code to use seven segment display. These 3 codes realy simple way using seven segment display. these are using in my microprocessor classes.
Wert deney1.asm -> no scan
Wert Deney2.asm -> Scan but BCD
Werrt Deney3.asm -> Scan with BCD.
By Basri KUL
This program incorporates the FV method for solving the Navier-Stokes equations using 2D, Cartesian grids and the staggered arrangement of variables. Variables are stored as 2D arrays. SIMPLE method is used for pressure calculation. UDS and CDS are implemented for the discretization of convective terms, CDS is used for the diffusive terms. The boundary conditions are set for the lid-driven cavity flow. Only steady flows are considered.
The 2D CFD Program NaSt2D
The program is a 2D solver for the incompressible, transient Navier-Stokes equations including the temperature equation and free boundary problems. It uses finite differences for discretization on a structured equidistant staggered grid, central and upwind (donor-cell) discretization of the convective parts and an explicit time stepping scheme. The free boundary value problems are treated with the MAC technique.
Solves the incompressible Navier-Stokes equations in a rectangular domain with prescribed velocities along the boundary. The standard setup solves a lid driven cavity problem.
