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Transonic turbulent boundary-layer flow over a circular-arc bump has been computed by high-resolution large-eddy simulation of the compressible Navier-Stokes equations. The inflow turbulence was prescribed using a new technique, in which known dynamical features of the inner and outer part of the boundary-layer were exploited to produce a standard turbulent boundary-layer within a short distance of the inflow. This method was separately tested for a flat plate turbulent boundary-layer, for which results compared well with direct numerical simulation databases. Simulation of the bump flow was carried out using high-order methods, with the dynamic Smagorinsky model used for sub-grid terms in the momentum and energy equations. Simulations were carried out at a Reynolds number of 233,000 based on bump length and free-stream properties upstream of the bump. At a back pressure equal to 0.65 times the stagnation pressure, a normal shock was formed near the bump trailing-edge and a peak mean Mach number of 1.16 was observed. Turbulence fluctuations decayed in the favourable pressure gradient region of the flow, before being amplified due to the shock interaction and boundary-layer separation. The effect of Reynolds number on turbulence intensity upstream of the shock is discussed in connection with a laminarisation parameter. With reference to turbulence modelling, anisotropy levels are not unreasonably high in the shock interaction region and shock unsteadiness was not found to be an issue. Of more relevance to the perceived poor performance of models for this type of flow may be the extremely rapid rise and decay of turbulence levels in the separated shear layer immediately under the shock-wave.

The cross-sectional sizes of the regularly patterned GaN nanorods (NRs) and InGaN/GaN quantum-well (QW) NRs of different heights and different hexagon orientations, which are grown on the patterned templates of different hole diameters, pitches, and crystal orientations, are compared. It is found that the cross-sectional size of the GaN NR, which is formed with the pulsed growth mode, is mainly controlled by the patterned hole diameter, and the thickness of the sidewall QW structure is mainly determined by the NR height. The cross-sectional size variation of GaN NR is interpreted by the quasi-three-dimensional nature of atom supply amount for precipitating a two-dimensional disk-shaped NR segment. The variation of the sidewall QW structure is explained by the condition of constituent atom supply in the gap volume between the neighboring NRs. Also, we compare the cathodoluminescence emission wavelengths among those samples of different growth conditions. Generally speaking, the QW NR with a smaller height, a larger cross-sectional size, or a larger pitch has a longer emission wavelength.

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With the nano-imprint lithography and the pulsed growth mode of metalorganic chemical vapor deposition, a regularly-patterned, c-axis nitride nanorod (NR) array of quite uniform geometry with simultaneous depositions of top-face, c-plane disc-like and sidewall, m-plane core-shell InGaN/GaN quantum well (QW) structures is formed. The differences of geometry and composition between these two groups of QW are studied with scanning electron microscopy, cathodoluminescence, and transmission electron microscopy (TEM). In particular, the strain state analysis results in TEM observations provide us with the information about the QW width and composition. It is found that the QW widths are narrower and the indium contents are higher in the sidewall m-plane QWs, when compared with the top-face c-plane QWs. Also, in the sidewall m-plane QWs, the QW width (indium content) decreases (increases) with the height on the sidewall. The observed results can be interpreted with the migration behaviors of the constituent atoms along the NR sidewall from the bottom.

The emerging blockchain technology shows promising potential to enhance industrial systems and the Internet of things (IoT) by providing applications with redundancy, immutable storage, and encryption. In the past a few years, many more applications in industrial IoT (IIoT) have emerged and the blockchain technologies have attracted huge amounts of attention from both industrial and academic researchers. In this paper we address the integration of blockchain and IIoT from the industrial prospective. A blockchain enabled IIoT framework is introduced and involved fundamental techniques are presented. Moreover, main applications and key challenges are addressed. A comprehensive analysis for the most recent research trends and open issues is provided associated with the blockchain enabled IIoT.

2009),"Numerical simulation of flow over an airfoil with a cross flow fan as a lift generating member in a new aircraft model", Aircraft Engineering and Aerospace Technology, Vol. 81 Iss 1 pp. 59-64 http:// dx.If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The paper seeks to perform a detailed numerical study of flow over a generic fan-wing airfoil and also attempts to modify the geometry for the improvement of the aerodynamic performance. Design/methodology/approach -Advanced computational fluid dynamics (CFD) technique has been employed for evaluation of the aerodynamic performance (e.g. lift/drag ratio) of a model problem. Numerical investigation starts with sensitivity studies to minimize domain size influence and grid dependency, followed by time-accurate transient calculations. A preliminary re-design exercise has been performed by analyzing the results of a current design. Findings -CFD predicted lift force agrees fairly well with the measurement data with about 6.55 per cent error, while drag force compares less favourably with about 12.59 per cent error. Both errors are generally acceptable for an engineering application of complex flow problems. Several key flow features observed previously by experiment have also been re-produced by simulation, notably the eccentric vortex motions in the blade interior and the stream "jet" flow outside the blades near the exit. With the modified geometry, there is a considerable lift/drag ratio improvement of about 29.42 per cent. The possible reasons for such a significant improvement have been discussed. Research limitations/implications -As it is the first step towards the detailed flow analysis of this type of model, a simpler blade shape rather than "real" one has been used. Practical implications -The paper provides a very useful source of information and could be used as guidance for further industry practice of unmanned aerial vehicles design. Originality/value -This paper is valuable for both academic researchers and industry engineers, especially those working in the area of high-lift wing design. The works presented are original. can be contacted at y.yao@kingston.ac.uk Study of flow over generic fan-wing airfoil Deepthi Duddempudi et al.

The growth of regularly patterned multi-section GaN nanorod (NR) arrays based on a pulsed growth technique with metalorganic chemical vapor deposition is demonstrated. Such an NR with multiple sections of different cross-sectional sizes is formed by tapering a uniform cross section to another through stepwise decreasing of the Ga supply duration to reduce the size of the catalytic Ga droplet. Contrast line structures are observed in either a scanning electron microscopy or transmission electron microscopy image of an NR. Such a contrast line-marker corresponds to a thin Ga-rich layer formed at the beginning of GaN precipitation of a pulsed growth cycle and illustrates the boundary between two successive growth cycles in pulsed growth. By analyzing the geometry variation of the contrast line-markers, the morphology evolution in the growth of a multi-section NR, including a tapering process, can be traced. Such a morphology variation is controlled by the size of the catalytic Ga droplet and its coverage range on the slant facets at the top of an NR. The comparison of emission spectra between single-, two-, and three-section GaN NRs with sidewall InGaN/GaN quantum wells indicates that a multi-section NR can lead to a significantly broader sidewall emission spectrum.