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A finite element method is used to study the effect of flow past a circular cylinder with an integral wake splitter. A fractional step algorithm is employed to solve the Navier‐Stokes and Energy equations with a Galerkin weighted residual formulation. The vortex shedding process is simulated and the effect of splitter addition on the time period of shedding is studied at a Reynolds number of 200 and a blockage ratio of 0.25. The effect of splitter and the Strouhal number and heat transfer augmentation per unit pressure drop has been investigated.

This study aims to investigate the effect of the simultaneous usage of active and passive methods (which in this case are rotational oscillation and attached splitter plate, respectively) on the flow and temperature fields to find an optimum situation which this combination results in heat transfer increment and drag reduction.

The method of the solution was based on finite volume discretization of Navier–Stokes equations. A dynamic grid is coupled with the solver by the arbitrary Lagrangian–Eulerian (ALE) formulation for modeling cylinder oscillation. Parametric studies were performed by altering oscillation frequency, splitter plate length and Reynolds number.

Oscillation in different frequencies was found to be complicated. Higher frequencies provide more heat transfer, but in the lock-on region, they bring remarkable increment to the drag coefficient. It was observed that simultaneous usage of oscillation and splitter plate may have both positive and negative effects on drag reduction and heat transfer increment. Finally F = 2 and L = 0.5 were chosen as an optimum combination.

In this study, the laminar incompressible flow and heat transfer from a confined rotationally oscillating circular cylinder with an attached splitter plate are investigated. Parametric studies are performed by changing oscillation frequency, splitter plate length and Reynolds number.

THE problem of silencing test houses for turbo‐jet engines is, acoustically, analogous to that for test beds for piston engines1 and 2 but is more complicated owing to the working conditions of turbo‐jet engines.

The purpose of this paper is to describe the first and novel beam splitting day-lighting system possessing highest possible solar transmission efficiency to provide illumination to the core and underground areas of any structure/building.

In this system, by using a number of individually pointable thin and light optical elements mounted on a top of structure/building, the solar light is concentrated. The concentrated beam is focussed to a secondary reflecting element which directs it to a beam splitter while passing through a Fresnel lens and a horizontal solar pipe. The beam splitter located inside the structure/building splits the solar beam into a number of secondary beams using a special arrangement of a number of inbuilt light guiding optical elements inside the beam splitter. The beam splitter produces a desired number of beams which are then redirected to the beam diffusers with the help of the solar pipe and the solar pipe joint which deflects the light at the angle of 90°.

The system considers the use of highly sophisticated and the highly efficient optical elements so that to attain the highest possible end-to-end efficiency of the system. The system has the highest potential to transport the solar energy to larger distances than all the available day-lighting systems and possesses the potential to be used for underground human colonisation.

The widespread adoption of such a system could substantially reduce energy consumption worldwide, which would contribute to bring down the increasing slope in the graph of greenhouse gases.

The paper presents the novel beam splitting day-lighting system.

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in ground‐effect.

Experiments were carried out in the University of Southampton's 3′×2′ wind tunnel. A variable length splitter plate was designed and manufactured in order to generate four boundary‐layer thicknesses at a selected measurement position. A single element inverted GA(W)‐1 aerofoil was then introduced to the flow at varying heights above the plate. Laser Doppler anemometry (LDA) and surface static pressure measurements (both on the aerofoil surface and on the splitter plate) were recorded.

The flow beneath the wing is found to be affected considerably by the presence of the boundary layer. As the boundary‐layer thickness is increased, the under‐wing pressure is observed to increase, hence resulting in decreased suction. Further, the LDA results indicate a modification to the wake profile. In particular, at low wing heights, the wake is observed to become entrained in the boundary layer, to differing degrees dependant on the boundary layer present and the wing height.

The acquisition of force values from the tests will have allowed further understanding of the “real world” implications of the presence of the boundary‐layer thicknesses on a wing in ground‐effect but this is not possible in the test facility used.

The aerodynamics of a wing in ground‐effect are of great interest for both lifting surfaces for aircraft and downforce generation in motorsport applications. The implications of this paper enhance the importance of understanding the boundary conditions present when wind tunnel testing for these applications.

Although the influence of the boundary layer on low ground clearance objects has been well documented, the methods used here, in particular the use of the pressure tapped splitter plate and LDA, allow a further insight into the explanations behind this influence.

TERRIFIC noise is one of the most undesirable features of aeronautical engineering. For the aeroplane passenger the introduction of the sound insulated cabin surmounted the difficulties some years ago, and the gradual perfection of the acoustic treatment has kept pace with the increased noise of faster airscrews and larger engines. Attention is nowadays given to ground test beds where the noise often reaches a painful intensity, and power plant manufacturers are finding it necessary to provide themselves with silenced test equipment.

For the realization of optical waveguide components, needed for photonic integrated circuits, multimode-interference based (MMI-based) devices are an excellent component class for the realization of low loss optical splitters. A promising approach to the manufacturing of these components is their embedding in thin glass sheets by ion-exchange diffusion processes, which has not yet been extensively studied. This study aims to significantly enhance the modeling of the diffusion process to support manufacturing of graded-index, MMI-based optical splitters.

The methods of design and analysis of MMI-based components are based on a step-index refractive index profile. In this work, fundamental correlations between the properties of the manufacturing ion-exchange process and the characteristics of the graded-index, MMI-based components are established. The refractive index profile is calculated with a proprietary solver based on the finite element method. Any further investigation with respect to parameter influence is based on the beam propagation method, specifically a finite difference based, semi-vectorial, wide-angle beam propagation algorithm. The influence of the parameters of the self-imaging effect is investigated. On this basis, different approaches for efficient power splitting with graded-index, MMI-based waveguide components are evaluated.

Easy approximations – mostly linear – can be found to model the dependencies of the investigated parameters. The resulting graded-index splitters are characterized by their low excess and insertion loss.

These findings are the first step in the direction of the semi-analytical modeling of the respective waveguide components to reduce the numerical effort.

We present 3D simulation of low loss splitters made on Lithium Niobate used in Mach-Zehnder interferometers. The interferometer consists of the splitters designed with photonic crystal structures at splitting point and bend positions for reduced size and loss, and straight sections as channel waveguides with high electro-optical coefficient r₃₃ of Lithium Niobate for reduced interactive length and modulating voltage π. The simulation shows a reduced coupling loss to 1.37 dB with the channel waveguides made suspended and V_π?is only 0.42V for interactive length of 200 um.

Purpose – Measures aimed at reducing intersection crashes have high potential to be cost effective since intersections constitute only a small part of the overall highway system but intersection-related crashes constitute more than 50% of all crashes in urban areas and over 30% in rural areas. Roundabouts are a proven safety countermeasure, but several issues that significantly affect both crash frequency and severity have been observed at both existing and new roundabouts. This chapter aims to provide guidance on roundabout selection and design criteria.

Methodology – The chapter first describes the most relevant criteria to be considered for choosing a roundabout. Then, after the explanation of the roundabout design process and a clear description of the roundabout classification, the chapter provides recommendations for all the steps of the geometric design, highlighting the main design features that contribute to the best safety performances, including speed control and sight distance checks. Finally, the chapter explains traffic control devices and facilities for pedestrians and cyclists.

Findings – Roundabout design needs to balance opposing demands and it is important to adopt a performance-based design approach within an iterative process. The most important performance check is the analysis of vehicle speeds through the roundabout, since achieving appropriate vehicular speeds has a very positive safety effect.