The evaluation of the far-field integral in the Green's function representation for steady Oseen flow

Consider the Green's function representation of an exterior problem in steady Oseen flow. The far-field integral in the formulation is shown to be zero

Flow control and high-lift performance for flying-wing manned Combat Air Vehicle Configurations by inserting lots

The objectives of the present study on Unmanned Combat Air Vehicles (UCAVs) are two-fold: first to control the flow by inserting leading-edge and cross-flow slots and analysing the viscous flow development over the outer panels of a flying-wing configuration to maximise the performance of the elevons control surfaces; second to predict high-lift performance particularly the maximum-lift characteristics. This is demonstrated using a variety of inviscid Vortex Lattice Method (VLM) and Euler, and viscous CFD Reynolds Averaged Navier-Stokes (RANS) methods. The computational results are validated against experiment measured in a wind tunnel. Two flying-wing planforms are considered based around a generic 40 ̊ edge-aligned configuration. The VLM predicts a linear variation of lift and pitching moment with incidence angle, and substantially under-predicts the induced drag. Results obtained from RANS and Euler agree well with experiment

Using eulerlets to model steady uniform flow past a circular cylinder

Consider uniform, steady flow past a circular cylinder at Reynolds numbers 26, 36 and 40 before the flow becomes unsteady. Model the flow by using eulerlets, new Green’s functions for Euler flow. This is the first time this eulerlet model has been used, introduced at the recent BETEQ 2017 International Conference. In addition, the far-field is also obtained by matching with oseenlets. Unlike existing Euler flow representations, the drag, wake eddies and far-field wake profile are all captured, and compare favourably with experiment

The theory and application of eulerlets

Consider a fixed body in a uniform flow field in the limit as the Reynolds number approaches infinity and the flow field remains steady. Instead of using standard techniques and theory for describing the problem, a new method is employed based upon the concept of matching two different Green’s integral representations over a common boundary, one given by approximations valid in the near-field and the other by approximations in the far-field. Further novelty arises from the choice of a near-field, that is, the Euler flow matched to an Oseen flow far-field. This entails introducing and defining eulerlets that are Green’s functions of the Euler equation. One important consequence of the model is the presence of a new Euler wake velocity not captured in standard models. This has a constant unchanging downstream profile and arises from the matching to the far-field Oseen wake velocity. It is then shown how this representation reduces to classical inviscid ideal flow aerodynamics when applied to flow past aerofoils and wings. It is also shown how it reduces to slender body flow theory. Finally, the formulation is tested on uniform flow past a circular cylinder for mean-steady subcritical laminar flow and turbulent flow. The inviscid impermeability boundary condition is used, the drag coefficient is specified, and a constant distribution of drag eulerlets is modeled. The forward flow separation and pressure drop in the wake are captured and compare favorably with experiment. The future expectation is the modeling of multiple general shaped bodies

Gravitational theoretical development supporting MOND

Conformal geometry is considered within a general relativistic framework. An invariant distant for proper time is defined and a parallel displacement is applied in the distorted space-time, modifying Einstein’s equation appropriately. A particular solution is introduced for the covariant acceleration potential that matches the observed velocity distribution at large distances from the Galactic Center, i.e. modified Newtonian dynamics. This explicit solution of a general framework that allows both curvature and explicit local expansion of space-time, thus reproduces the observed flattening of galaxys’ rotation curves without the need to assume the existence of dark matter. The large distance expansion rate is found to match the speed of a spherical shock wave

Modelling the electrical resistivity of concrete with varied water and chloride contents

The electrical resistivity of concrete is an important property in the assessment of reinforcement corrosion in concrete and an essential parameter in the design and operation of cathodic protection for reinforced-concrete (RC) structures. Water and chloride contents in concrete are highly variable in RC structures in real-world hostile environments, meaning that characterisation of their coupled effects on concrete electrical resistivity is important. The currently available models are investigated in this paper. As all the current models are purely empirical, an improvement with a semi-empirical model is proposed. The improvement highlights the intrinsic linkage between concrete electrical resistivity and water content and the pore size distribution of concrete. The proposed model was tested using two sets of experimental data and was also compared with other two empirical models

Relating Differently to Intrusive Images: The Impact of Mindfulness Based Cognitive Therapy (MBCT) on Intrusive Images in Patients With Severe Health Anxiety (Hypochondriasis).

Recurrent distressing intrusive images are a common experience in hypochondriasis. The aim of the current study was to assess the impact of Mindfulness-Based Cognitive Therapy (MBCT) for hypochondriasis on the occurrence and nature of distressing intrusive imagery in hypochondriasis. A semi-structured interview was used to assess intrusive imagery, and an adapted version of the Southampton Mindfulness Questionnaire (SMQ) was used to assess participants’ relationship with their intrusive images. A consecutive series of participants (N = 20) who were receiving MBCT for hypochondriasis as part of an ongoing research program were assessed prior to participating in an 8-week MBCT intervention, immediately following the intervention, and at three month follow-up. As compared to the baseline assessment, the frequency of intrusive images, the distress associated with them, and the intrusiveness of the images were all significantly reduced at the post-MBCT assessment. Participants’ adapted SMQ scores were significantly increased following the MBCT intervention, suggesting that participants’ relationship with their intrusive images had changed in that they had developed a more ‘mindful’ and compassionate response to the images when they did occur. Effect sizes from pre- to post-intervention were medium to large (Cohen’s d = 0.75 - 1.50). All treatment gains were maintained at 3 month follow-up. Results suggest that MBCT may be an effective intervention for addressing intrusive imagery in hypochondriasis

Central nervous system relapse of diffuse large B-cell lymphoma in the rituximab era: results of the UK NCRI R-CHOP-14 versus 21 trial

Background: Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is associated with a dismal prognosis. Here, we report an analysis of CNS relapse for patients treated within the UK NCRI phase III R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) 14 versus 21 randomised trial. Patients and methods: The R-CHOP 14 versus 21 trial compared R-CHOP administered two- versus three weekly in previously untreated patients aged ≥18 years with bulky stage I-IV DLBCL (n = 1080). Details of CNS prophylaxis were retrospectively collected from participating sites. The incidence and risk factors for CNS relapse including application of the CNS-IPI were evaluated. Results: 177/984 patients (18.0%) received prophylaxis (intrathecal (IT) methotrexate (MTX) n = 163, intravenous (IV) MTX n = 2, prophylaxis type unknown n = 11 and IT MTX and cytarabine n = 1). At a median follow-up of 6.5 years, 21 cases of CNS relapse (isolated n = 11, with systemic relapse n = 10) were observed, with a cumulative incidence of 1.9%. For patients selected to receive prophylaxis, the incidence was 2.8%. Relapses predominantly involved the brain parenchyma (81.0%) and isolated leptomeningeal involvement was rare (14.3%). Univariable analysis demonstrated the following risk factors for CNS relapse: performance status 2, elevated lactate dehydrogenase, IPI, >1 extranodal site of disease and presence of a 'high-risk' extranodal site. Due to the low number of events no factor remained significant in multivariate analysis. Application of the CNS-IPI revealed a high-risk group (4-6 risk factors) with a 2- and 5-year incidence of CNS relapse of 5.2% and 6.8%, respectively. Conclusion: Despite very limited use of IV MTX as prophylaxis, the incidence of CNS relapse following R-CHOP was very low (1.9%) confirming the reduced incidence in the rituximab era. The CNS-IPI identified patients at highest risk for CNS recurrence. ClinicalTrials.gov: ISCRTN number 16017947 (R-CHOP14v21); EudraCT number 2004-002197-34

Vegetation forcing modulates global land monsoon and water resources in a CO2-enriched climate

The global monsoon is characterised by transitions between pronounced dry and wet seasons, affecting food security for two-thirds of the world’s population. Rising atmospheric CO2 influences the terrestrial hydrological cycle through climate-radiative and vegetation-physiological forcings. How these two forcings affect the seasonal intensity and characteristics of monsoonal precipitation and runoff is poorly understood. Here we use four Earth System Models to show that in a CO2-enriched climate, radiative forcing changes drive annual precipitation increases for most monsoon regions. Further, vegetation feedbacks substantially affect annual precipitation in North and South America and Australia monsoon regions. In the dry season, runoff increases over most monsoon regions, due to stomatal closure-driven evapotranspiration reductions and associated atmospheric circulation change. Our results imply that flood risks may amplify in the wet season. However, the lengthening of the monsoon rainfall season and reduced evapotranspiration will shorten the water resources scarcity period for most monsoon regions