An experimental and numerical CFD study of turbulence in a tundish container

This paper describes work performed at IRSID/USINOR in France and the University of Greenwich, UK, to investigate flow structures and turbulence in a water-model container, simulating aspects typical of metal tundish operation. Extensive mean and fluctuating velocity measurements were performed at IRSID using LDA to determine the flow field and these form the basis for a numerical model validation. This apparently simple problem poses several difficulties for the CFD modelling. The flow is driven by the strong impinging jet at the inlet. Accurate description of the jet is most important and requires a localized fine grid, but also a turbulence model that predicts the correct spreading rates of jet and impinging wall boundary layers. The velocities in the bulk of the tundish tend to be (indeed need to be) much smaller than those of the jet, leading to damping of turbulence, or even laminar flow. The authors have developed several low-Reynolds number (low-Re) k–var epsilon model variants to compute this flow and compare against measurements. Best agreement is obtained when turbulence damping is introduced to account not only for walls, but also for low-Re regions in the bulk – the k–var epsilon model otherwise allows turbulence to accumulate in the container due to the restricted outlet. Several damping functions are tested and the results reported here. The k–ω model, which is more suited to transitional flow, also seems to perform well in this problem.

Fostering 'habits of reflection, independent study and free inquiry': an analysis of the short-lived phenomenon of General/Liberal Studies in English vocational education and training

In 1957, 12 years after the end of World War II, the Ministry of Education issued Circular 323 to promote the development of an element of ‘liberal studies’ in courses offered by technical and further education (FE) colleges in England. This was perceived to be in some ways a peculiar or uncharacteristic development. However, it lasted over 20 years, during which time most students on courses in FE colleges participated in what were termed General or Liberal Studies classes that complemented and/or contrasted with the technical content of their vocational programmes. By the end of the 1970s, these classes had changed in character, moving away from the concept of a ‘liberal education’ towards a prescribed diet of ‘communication studies’. The steady decline in apprenticeship numbers from the late 1960s onwards accelerated in the late 1970s, resulting in a new type of student (the state-funded ‘trainee’) into colleges whose curriculum would be prescribed by the Manpower Services Commission. This paper examines the Ministry’s thinking and charts the rise and fall of a curriculum phenomenon that became immortalised in the ‘Wilt’ novels of Tom Sharpe. The paper argues that the Ministry of Education’s concerns half a century ago are still relevant now, particularly as fresh calls are being made to raise the leaving age from compulsory education to 18, and in light of attempts in England to develop new vocational diplomas for full-time students in schools and colleges.