Improving CFD prediction of drag on Paralympic tandem athletes: influence of grid resolution and turbulence model

Tandem cycling enables visually impaired athletes to compete in cycling in the Paralympics. Tandem aerodynamics can be analysed by track measurements, wind-tunnel experiments and numerical simulations with computational fluid dynamics (CFD). However, the proximity of the pilot (front) and the stoker (rear) and the associated strong aerodynamic interactions between both athletes present substantial challenges for CFD simulations, the results of which can be very sensitive to computational parameters such as grid topology and turbulence model. To the best of our knowledge, this paper presents the first CFD and wind-tunnel investigation on tandem cycling aerodynamics. The study analyses the influence of the CFD grid topology and the turbulence model on the aerodynamic forces on pilot and stoker and compares the results with wind-tunnel measurements. It is shown that certain combinations of grid topology and turbulence model give trends that are opposite to those shown by other combinations. Indeed, some combinations provide counter-intuitive drag outcomes with the stoker experiencing a drag force up to 28% greater than the pilot. Furthermore, the application of a blockage correction for two athlete bodies in close proximity is investigated. Based on a large number of CFD simulations and validation with wind-tunnel measurements, this paper provides guidelines for the accurate CFD simulation of tandem aerodynamics.     

Les Effets de Coopération et de Feedback par les Compagnons de Classe sur la Performance Orthographique

European Journal of Psychology of Education -     

Using the dynamic approach to school improvement to promote quality and equity in education: a European study

Educational Assessment, Evaluation and Accountability - This paper presents the results of a European study investigating the extent to which the Dynamic Approach to School Improvement (DASI) can...     

Managing academic personnel flow at universities∗∗

Abstract

Universities experience increasing difficulty in staffing their academic positions. Attracting and retaining highly qualified employees is a general problem that has received much attention in recent HRM literature. But several authors have claimed that the academic career has lost much of its attractiveness. This paper presents seven levers that universities may use to enhance their recruitment and retention power on a difficult job market. Suggestions are made based on experience from innovative organisations, both universities and business organisations. Special attention is given to the creation of multiple and flexible career paths within academia. We contend that a successful application of these suggestions will require major cultural and institutional change at universities.     

A dynamic approach to school improvement: main features and impact

This paper refers to the dynamic approach to school improvement (DASI) which attempts to contribute to the merging of educational effectiveness research and school improvement. The main underlying assumptions and the implementation phases of DASI are discussed. Moreover, a study aiming to compare the impact of DASI in helping schools to reduce bullying is presented. The results reveal that DASI has a stronger impact on improving school factors and reducing bullying than other approaches to school improvement. Suggestions for further research investigating the sustainability of DASI on school effectiveness are provided and policy implications are drawn.     

Low-dose exercise training does not influence cardiac autonomic control in healthy sedentary men aged 55 – 75 years

Abstract

The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 ± 6.1 years (mean ± s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2 – 3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 ± 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption ([Vdot]O_2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55 – 75 years.