Medical Applications for 3D Printing: Recent Developments

This is a review of some of the recent developments in the application of 3D printing to medicine. The topic is introduced with a brief explanation as to how and why 3D is changing practice, teaching, and research in medicine. Then, taking recent examples of progress in the field, we illustrate the current state of the art. This article concludes by evaluating the current limitations of 3D printing for medical applications and suggesting where further progress is likely to be made

Investigation of improved aerodynamic performance of isolated airfoils using CIRCLE method

CC BY-NC-ND licenseThe PhD research of Moin U Ahmed is partly sponsored by Cummins Turbo Technologies Ltd and partly by Queen Mary University of London

Dynamic Modeling of Solar Dynamic Components and Systems

The purpose of this grant was to support NASA in modeling efforts to predict the transient dynamic and thermodynamic response of the space station solar dynamic power generation system. In order to meet the initial schedule requirement of providing results in time to support installation of the system as part of the initial phase of space station, early efforts were executed with alacrity and often in parallel. Initially, methods to predict the transient response of a Rankine as well as a Brayton cycle were developed. Review of preliminary design concepts led NASA to select a regenerative gas-turbine cycle using a helium-xenon mixture as the working fluid and, from that point forward, the modeling effort focused exclusively on that system. Although initial project planning called for a three year period of performance, revised NASA schedules moved system installation to later and later phases of station deployment. Eventually, NASA selected to halt development of the solar dynamic power generation system for space station and to reduce support for this project to two-thirds of the original level

Low Reynolds number proprotor aerodynamic performance improvement using the continuous surface curvature design approach

Low Reynolds number blade profiles of Re_C =10^5 to 2*10^5 as as based on chord length and used for small unnamed air vehicles, and near space applications are investigated for single and counter-rotating (coaxial) proprotors, i.e. acting as rotors or propellers. Such profiles are prone for early stall, significantly reducing their maximum lift to drag ratio. Two profiles previously designed by our continuous surface curvature design approach named as CIRCLE are investigated in order to improve the performance of the proprotors. The profiles are redesigns of the common symmetric NACA0012 and asymmetric E387 profiles. Using general arguments based on composite efficiency and rotor’s lift to drag ratio, the performance envelope is noticeably increased when using the redesigned profiles for high angles of attack due to stall delay. A new approach is derived to account for the distance between the rotors of a coaxial proprotor. It is coupled with a blade element method and is verified against experimental results. Single and coaxial CIRCLE-based proprotors are investigated against the corresponding non CIRCLE-based proprotors at hover and axial translation. Noticeable improvements are observed in thrust increase and power reduction at high angles of attack of the blade’s profiles, particularly for the coaxial configuration. Plots of thrust, torque, power, composite efficiency and aerodynamic efficiency distributions are given and analysed

A numerical study on the influence of curvature ratio and vegetation density on a partially vegetated U-bend channel flow

Aquatic vegetation dramatically shifts the main flow, secondary flow and turbulent structures in a meandering channel. In this study, hydrodynamics in a bending channel with a vegetation patch (VP) has been numerically studied under the variation of curvature ratios (CRs=0.5, 1.0, 1.5, 2.0) and the vegetation density i.e. Solid Volume Fractions (SVF=1.13%, 4.86%). Both effects on vegetation shear flow, helical flow, bed shear stress and bulk drag coefficients are studied in twelve cases by using Ansys Fluent package. Unsteady Reynolds Averaging Navier-Stokes (URANS) framework coupled with the Reynolds Stress turbulence Model (RSM) and Volume Of Fluid (VOF) approach is successfully applied to predict the entire flow field including multi-circulation cells as well as the free surface. The conclusions are summarized as three points. Firstly, an increase of CR moves the main circulation cell and thalweg's location towards the outer bank, while decreasing the drag coefficients in streamwise and spanwise. However, the CR weakly affects the normalised shear flow velocity profiles and dominant eddy frequencies downstream of the VP. Secondly, the trend of the dominant shedding frequency to fall with the increase of SVF that has been known only for SVF<3.4% is extended up to 10.4%. Furthermore, an opposite trend is found between the frequency and SVF for 10.4%<SVF<20%. Thirdly, a newly proposed patch dimensionless frequency number, , links Stp and SVF, where N is the number of stems in the patch. This number stays almost constant for each case series regardless of the variation of SVF (for SVF<10.4%). We also conclude that is strongly determined by the patch shape factor, mildly influenced by the patch Reynolds number, but it excludes the influence of the SVF and N. The insights from the present study unveil the complicated eco-hydro-morphic interactions among the bio-mass density, turbulent flow and channel meanders’ variation. It provides a better understanding of natural bending river systems’ development and fundamentals for the recovery of urban channel ecosystems by vegetated re-meandering

Surface curvature effects on the tonal noise performance of a low Reynolds number aerofoil

The support of the UK turbulence consortium for providing national computing time under Grant No. EP/L000261/1 was acknowledged. The authors acknowledge the Royal Society (Grant No. IE131709) and NFSC (Grant No. NFSC-5141130130, 51376015 and 51476005) that funded the visit to Beihang D5 wind tunnel and the production of the models. The PhD research of Xiang Shen is funded by China Scholarship Council (CSC)/ Queen Mary Joint PhD scholarship and is supervised by Theodosios Korakianitis and Eldad Avital

Hydrodynamic assessment of a dual-rotor horizontal axis marine current turbine

© 2018 Authors. The hydrodynamic performance of a dual-rotor horizontal axis marine turbine (HAMCT) is investigated for the power gain in operating the rear rotor without blade-pitch control. This kind of turbine can be advantageous for a rectilinear tidal current of reversing directions, where each rotor blade is optimally fixed-pitched towards its upstream velocity. The blade element momentum (BEM) method is coupled with the Park wake model. A generic three-blade turbine is shown to gain up to 20% in the coefficient of power CPas relative to the front rotor CPwhen operating the rear rotor at the same tip speed ratio (TSR) as the front one, gaining overall CPup to 0.55. Analytic model is derived to backup the estimate of power gain. Plots for turbine performance variation with TSR and profile hydrodynamic efficiency are given, and analysed for lab and small-medium size turbines