A uniform asymptotic solution is presented for the electromagnetic diffraction by a wedge with impedance faces and included angles equal to 0 (half-plane), pi /2 (right-angled wedge), (two-part plane) 3 wedge). The incident field plane wave of arbitrary polarization, obliquely axis wedge. formal solution, which expressed in terms an integral, was obtained generalized reflection method. careful study singularities integrand made before evaluation integral carried out. performed taking into...

In the present paper, we verify effectiveness of two-relaxation-time (TRT) collision operator in reducing boundary slip computed by immersed boundary-lattice Boltzmann method (IB-LBM). linear TRT, decompose distribution function into symmetric and antisymmetric components define relaxation parameters for each part. The Chapman-Enskog expansion indicates that one time component is related to kinematic viscosity. Rigorous analysis shear flows reveals part controls velocity gradient, velocity,...

A GPU code has been developed for a phase-field lattice Boltzmann (PFLB) method, which can simulate the dendritic growth with motion of solids in dilute binary alloy melt. The accelerated PFLB method implemented using CUDA C. equiaxed shear flow and settling condition have simulated by code. It confirmed that simulations were efficiently introducing computation. characteristic dendrite morphologies depend on melt could also be simulations.

Generalized impedance boundary conditions are derived for a planar, homogeneous, magnetic dielectric slab grounded by perfect electric conducting plane and coated, circular cylinder. By invoking the duality principle, generalized resistive also obtained transparent slab. In method followed here, it is not necessary to have prior knowledge of Fresnel reflection and/or transmission coefficients configuration under study obtain conditions. The developed here planar recover exact (for slab)...

The Wiener-Hopf technique is used to solve two canonical problems. first problem considered the electromagnetic (EM) diffraction, by a planar surface with an impedance discontinuity (two-part surface), of arbitrarily polarized plane wave obliquely incident axis two-dimensional objects. second considers EM diffraction half-plane equal impedances on both sides. solutions obtained are cast in matrix notation which useful for exact formal expressed terms integrals can be asymptotically...

An immersed boundary-lattice Boltzmann method (IB-LBM) using a two-relaxation time model (TRT) is proposed. The collision operator in the lattice equation modeled two relaxation times. One of them used to set fluid viscosity and other for numerical stability accuracy. A direct-forcing utilized treatment boundary. multi-direct forcing also implemented precisely satisfy boundary conditions at Circular Couette flows between stationary cylinder rotating are simulated validation proposed method....

A scheme for controlling the surface wave behaviour on printed planar antennas is presented. The approach to add conducting strips both top and, if necessary, bottom of substrate. applied a rectangular microstrip antenna with electrically thick (~0.1λd) An optimisation algorithm employed design strip parameters in order obtain best performance antenna, namely, low side and back lobe levels main beam without ripples. optimal then fabricated tested. Measured results are presented assess...

We present Canopus, the AO bench for Gemini's Multi Conjugate Adaptive Optics System (GEMS), a unique facility Gemini South telescope located at Cerro Pachon in Chile. The MCAO system uses five laser beacons conjunction with different natural guide stars configurations. A deployable fold mirror Acquisition and Guiding Unit (A&G) sends beam to entrance of bench. is split within Canopus into three main components: two sensing paths output corrected science beam. Light from constellation...

An immersed boundary method based on a finite difference lattice Boltzmann (IB-FDLBM) is presented. The FDLBM solves the discrete equation including an additional collision term by using schemes. works as negative viscosity in macroscopic level and allows us to alter fluid while keeping other relevant parameters of simulation fixed. employs direct-forcing method, which utilizes external forces at Lagrangian points embedded boundaries impose no-slip condition. Several benchmark simulations...

Abstract Given the severe implications of climate change and ocean acidification (OA) for marine ecosystems, there is an urgent need to quantify ecosystem function in present‐day conditions determine impacts future changes environmental conditions. For tropical coral reefs that are acutely threatened by these effects, metabolism benthic communities provides several metrics suitable this purpose, but application infrastructure manipulate measure community responses not fully realized. To...

An optical true-time delay (OTTD) engine based on a polynomial White cell (quadratic) is designed and simulated with commercially available components time increment of at least 25 ps for wideband beam steering in the frequency range 2-18 GHz. The quantification aberration losses show first that null are about 5.0 dB. However, longer arms, there an additional loss 3.2 dB/delay each travels arm lens train used as element compared same generated without train. We present design simulation...

Immersed boundary-lattice Boltzmann methods (IB-LBM) with the single-relaxation time (SRT) cause non-physical distortion in fluid velocity when Reynolds number is low, i.e. relaxation τ high, and IB-LBM requires high spatial resolution to stably simulate flows. An immersed boundary-finite difference lattice method (IB-FDLBM) using two-relaxation times (TRT) therefore proposed this study low flows accurately. Benchmark problems such as circular Couette flows, past a cylinder sphere at various...

A scheme is presented here to lower the free-space coupling loss large mode area (LMA) photonic crystal fiber (PCF). numerical study (using optics software for layout and optimization/beam propagation method) has been performed which demonstrates that major source of due aberrations present in optical system bulk optics) creating a beam with appropriate size couple into LMA-35. We show by carefully choosing single or multiple aspheric lenses wavefront can be minimized LMA-PCF reduced only 0.5 dB.

The solution for the two-dimensional (2-D) Green's function a wedge with impedance faces is presented. important feature of this that there are no restrictions on locations source and observation points-they can be anywhere. Its development proceeds along two separate lines: one when or point far from vertex another it close. Much effort has been expended in these formulations obtaining forms which efficient to evaluate numerically. This involved deforming various contours integration so...

An accurate uniform asymptotic technique to calculate the radiated field from a magnetic current moment situated on surface of circular cylinder coated with thin dielectric layer has been developed. Using Watson transform, slowly convergent radially propagating series representation for fields is converted into rapidly circumferentially representation. shadow region solution then obtained by employing method steepest descent. By modifying in an appropriate manner, lit that reduces...

The applicability of the immersed boundary-finite difference lattice Boltzmann method (IB-FDLBM) to high Reynolds number flows about a circular cylinder is examined. Two-dimensional simulations past stationary are carried out for wide range number, Re, i.e., 1 ≤ Re 1×10 5 . An boundary-lattice (IB-LBM) also used comparison. Then free-falling cylinders simulated demonstrate feasibility predicting moving particles at numbers. main conclusions obtained as follows: (1) steady and unsteady well...

The high frequency electromagnetic diffraction by a finite length resistive strip attached to wedge with equal impedance faces is presented. problem considered two dimensional where the incident field plane wave polarized TM or TE axis of wedge. Since scatterer has points diffraction, original can be first broken up into simpler canonical problems which, due symmetry scatterer, obtained proper combination special cases well known Maliuzhinets solution. A uniform asymptotic solution these...

A full-wave analysis using the Wiener-Hopf procedure and generalized scattering matrix technique (WH/GSMT) is applied to study EM field propagation of conductor-backed coplanar waveguides. The power leakage from dominant mode effect finite extent lateral ground planes are emphasized. WH/GSMT developed especially suitable for studying planar transmission lines with conductors extent.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The electromagnetic diffraction of a plane wave (transverse electric case) by two‐part material coated perfectly conducting ground and material‐coated half is studied using the Maliuzhinets method. Each coatings assumed to be electrically thin so that it can replaced in analysis generalized impedance boundary condition 0( t ), where corresponding coating thickness. To solve each value problems completely, one needs impose an additional constraint which determined here matching approximate...