Shock interactions in continuum and rarefied conditions employing a novel gas-kinetic scheme

Shock interactions can have a significant impact on heating rates and aerodynamic performance of hypersonic vehicles. The study presents different shock interactions in partially rarefied hypersonic flows predicted employing a recently developed gas-kinetic scheme for diatomic gases with rotational degrees of freedom. The new gas-kinetic schemes will be presented along with shock/wave boundary interactions as well as Edney Type IV shock–shock interactions. Various levels of rarefaction have been considered to highlight the effect of thermal relaxation between the translational and rotational modes. In addition, for the Edney test case, the imposed wall temperature on the shock-generating wedge and the cylinder surface has been varied, to evaluate the importance of the boundary layer thickness in the interaction region

Assessment of Implicit Implementation of the AUSM+ Method and the SST Model for Viscous High Speed Flow

No abstract available

Calibration of the 7—equation transition model for high Reynolds flows at low mach

The numerical simulation of flows over large-scale wind turbine blades without considering the transition from laminar to fully turbulent flow may result in incorrect estimates of the blade loads and performance. Thanks to its relative simplicity and promising results, the Local-Correlation based Transition Modelling concept represents a valid way to include transitional effects into practical CFD simulations. However, the model involves coefficients that need tuning. In this paper, the γ—equation transition model is assessed and calibrated, for a wide range of Reynolds numbers at low Mach, as needed for wind turbine applications. An aerofoil is used to evaluate the original model and calibrate it; while a large scale wind turbine blade is employed to show that the calibrated model can lead to reliable solutions for complex three-dimensional flows. The calibrated model shows promising results for both two-dimensional and three-dimensional flows, even if cross-flow instabilities are neglected

CFD code comparison for 2D airfoil flows

The current paper presents the effort, in the EU AVATAR project, to establish the necessary requirements to obtain consistent lift over drag ratios among seven CFD codes. The flow around a 2D airfoil case is studied, for both transitional and fully turbulent conditions at Reynolds numbers of 3 × 106 and 15 × 106. The necessary grid resolution, domain size, and iterative convergence criteria to have consistent results are discussed, and suggestions are given for best practice. For the fully turbulent results four out of seven codes provide consistent results. For the laminar-turbulent transitional results only three out of seven provided results, and the agreement is generally lower than for the fully turbulent case

Latest results from the EU project AVATAR: aerodynamic modelling of 10 MW wind turbines

This paper presents the most recent results from the EU project AVATAR in which aerodynamic models are improved and validated for wind turbines on a scale of 10 MW and more. Measurements on a DU 00-W-212 airfoil are presented which have been taken in the pressurized DNW-HDG wind tunnel up to a Reynolds number of 15 Million. These measurements are compared with measurements in the LM wind tunnel for Reynolds numbers of 3 and 6 Million and with calculational results. In the analysis of results special attention is paid to high Reynolds numbers effects. CFD calculations on airfoil performance showed an unexpected large scatter which eventually was reduced by paying even more attention to grid independency and domain size in relation to grid topology. Moreover calculations are presented on flow devices (leading and trailing edge flaps and vortex generators). Finally results are shown between results from 3D rotor models where a comparison is made between results from vortex wake methods and BEM methods at yawed conditions

Contribution of respiratory syncytial virus (RSV) among patients <15 years hospitalized with severe acute respiratory infection (SARI) in Milan, 2014-2017

Aim: Respiratory syncytial virus (RSV) infections may range from cold to severe acute respiratory infection (SARI) and are responsible for substantial pediatric morbidity. We describe the results of RSV molecular detection in respiratory samples collected from children <15 years hospitalized with SARI in Milan (Italy) during four consecutive years. Method: From January 1st, 2014, to December 31st, 2017, 3013 respiratory samples (2826 upper-respiratory-tract [UTR] and 187 lower-respiratory-tract [LTR] specimens) collected from as many children <15 years hospitalized with SARI at an University hospital in Milan were analysed. After DNA/RNA extraction, samples were tested by a multiplex real-time PCR to detect RSV and other respiratory viruses. Results: 571 (19%) respiratory samples tested RSV-positive. RSV-positivity rate by sample type was similar (URT vs LRT: 19.2% vs 14.4%; p=0.09). The median age of RSV-positive cases was 6.6 months (inter-quartile range: 17.2 months); 52.2% were males. 62.2% (355/571) of RSV-positive samples were identified in children <1 year and 12.4% (71/571) in those <1 month. RSV was detected throughout the study period; 59.2% (338/571) cases were identified during seasonal peaks (December-February). In 49.9% (285/571) of RSV-positive samples at least another virus (mainly Rhinovirus: 45.9%) was detected, particularly (60%; 171/285) in samples collected from children >1 year. Conclusions: Accordingly to other studies, RSV was detected in 19% of hospitalized-SARI cases <15 years, mainly in children <1 year and in December-February. Sampling of upper or lower airways resulted in similar RSV-positivity rate. Routine molecular testing to detect RSV is warranted to improve clinical management of pediatric patients

Epidemiological and molecular characteristics of HPEV infection in children<6 months hospitalized with symptoms of sepsie-like illness, northen Italy, 2015-2018

BACKGROUND. Human parechoviruses (HPeVs) are widespread pathogens belonging to the Picornaviridae family and currently divided into 19 genotypes. HPeV infections can be associated with severe clinical manifestations, such as sepsis-like illness, particularly in youngest children. The epidemiological and molecular characteristics of HPeV infections observed in children <6 months hospitalized with symptoms of sepsis-like illness were investigated. METHODS. From January 1st, 2015, to December 31st, 2018, clinical samples (cerebrospinal fluid samples and/or blood samples) were collected for diagnosis of HPeV infection from 193 patients (median age: 21 days, range: 1 day - 6 months) hospitalized with symptoms of sepsis-like illness, in two hospitals of Northern Italy. HPeV-RNA was detected by real-time RT-PCR (target 5\u2019UTR) and a portion of HPeV VP3/VP1 junction (nt. 2159\u20132458) was sequenced for typing and molecular characterization. RESULTS. 14% (27/193) of patients with symptoms of sepsis-like illness tested HPeV-positive. 26/27 (96.3%) HPeV-cases were <3 months and 20/27 (74.1%) <1 month. HPeV-positive cases were detected throughout the study period, mainly (12/27; 44.4%) during the summertime (June-August). 17/27 (63%) HPeV-positive samples were molecularly characterized: 16 resulted HPeV-3 and 1 HPeV-5. CONCLUSIONS. HPeV infection was identified in 14% of children <6 months with symptoms of sepsis-like illness. Almost all HPeV infections were detected in children <3 months and mainly during the summertime; almost all molecularly characterized HPeV belonged to type 3. Including HPeV molecular detection in routine diagnostic tests would allow estimating the burden of HPeV infection and improving clinical management of pediatric patients

Emergence of divergent enterovirus (EV) D68 sub-clade D1 strains, northern Italy, September to October 2018

An enterovirus D68 (EV-D68) outbreak was recognised at a major tertiary centre and research hospital in Milan and Pavia in the Lombardy region, northern Italy, respectively, between September and October 2018. Here, we present the molecular and clinical characteristics of the confirmed EV-D68 cases detected during the outbreak sustained by EV-D68 sub-clade D1 strains

The influence of learning styles on knowledge acquisition in public sector management

This research note outlines a project designed to investigate the role of training institutions in providing effective training and development programmes for managers. The investigation is being carried out in the light of recent criticisms levelled against the nature of formal learning environments prevalent in most institutional settings. The traditional role of trainers and developers as the providers of knowledge and skills for the development of competent managers runs contrary to recent findings, which suggest that managers learn more effectively in informal settings, rather than the formal settings evident in many development programmes. The idea that explicitly extracted competencies are the target every manager should aim for to improve their effectiveness is also challenged because competencies alone are no longer regarded as a sufficient criterion for success. Recent research has attached greater importance to the need for helping managers to see knowledge as a social phenomenon, and one factor that might distinguish successful managers from others is tacit knowledge (Wagner & Sternberg, 1987; Argyris, 1999). A major focus of this study is to explore the possibility that the level and content of tacit knowledge acquired by managers may be influenced by their individual learning styles, and the degree to which their dominant styles are matched with the context of their work environment