Experimental and numerical modelling of aerated flows over stepped spillways

Stepped spillways are a popular design choice for reservoir overflows due to the high rates of energy dissipation and air entrainment compared to smooth spillways. Air entrainment is important in spillway flows as it affects the pressures acting on the spillway surface, which in adverse conditions can damage the spillway. Air entrainment also causes flow bulking which increases the depth of flow. This study presents free surface and pressure data for aerated flows over an experimental stepped spillway, with pressures measured at different positions across the width of the channel. Within the step cavities, recirculating vortices are observed in both the stream-wise and cross-stream directions, with the direction of circulation alternating at each subsequent step. These 3D effects cause the pressures acting on the step edges to vary across the width of the channel. The Volume of Fluid (VOF) and Eulerian multiphase numerical models are used to predict flows over the spillway. The Eulerian multiphase model shows high levels of air entrainment and is able to predict the position of the free surface to reasonable accuracy. The VOF model, conversely, does not show any air entrainment and therefore under predicts the position of the free surface. The accuracy to which each numerical model predicts pressures on the step faces varies depending on the measurement location. Both of the numerical models accurately simulate the direction of circulation of the 3D vortices within the step cavities. Simulations with varying channel widths, conducted using the VOF model, show that the pattern of 3D vortices repeats as the channel width is increased

Smart water metering as a non-invasive tool to infer dwelling type and occupancy – Implications for the collection of neighbourhood-level housing and tourism statistics

The international rollout of advanced metering infrastructure (AMI) in the residential water supply sector affords tremendous benefits in driving water-use efficiencies, accurate billing and network management (e.g. leak detection). AMI, using ‘smart meters’ fitted at a dwelling level, record water consumption at high temporal resolution. Since water is typically only consumed when householders are present, these data could offer a non intrusive means of inferring dwelling occupancy patterns. These insights could have a range of benefits dependent upon the spatiotemporal scale and the intended application – our interest is in the potential of these data to identify dwelling type, specifically to identify dwellings that have occupancy patterns associated with tourism, such as second homes or short-term holiday rentals. We focus on these data in a UK context and draw on data rarely available for academic research. Our data relate to a sample of dwellings in Devon and Cornwall, South West England. They capture high-temporal resolution water consumption during Covid-19 ‘lockdown’ and ‘staycation’ periods, providing a unique opportunity to demonstrate that these data can reveal the unusually pronounced property-level occupancy trends evident during this period. We apply Non-Intrusive Occupancy Monitoring (NIOM) to extract dwelling-level occupancy status (occupied/unoccupied) on a day-by-day basis. We group properties according to their occupancy trends, inferring a set of properties that exhibit occupancy characteristics associated with tourism. We demonstrate that these show correspondence with underlying in dicators of tourism activity, drawn from AirDNA records of short-term tourist rental properties in this area. Ongoing global rollout of AMI means that these data will be routinely available at the dwelling level and we reflect on the benefits they could provide in generating near real time insights into dwelling occupancy. Drawing on our collaboration with the Office for National Statistics (the UKs national statistical institute) we outline the considerable potential that these data and approaches could offer in the collation of small area housing and tourism statistics

Medicines containing codeine: perspectives of medical professionals in the Republic of Ireland

Aims: The aim of the study was to examine prescribing professional's perceptions on prescribed and OTC medicines, containing codeine in the Republic of Ireland. A secondary aim was to examine perceptions on codeine dependence, screening and treatment. Methods: A cross sectional study of a nationally representative group of prescribing professionals was conducted using a questionnaire containing a number of open and closed ended items. Data were analysed using SPSS version 21 and content analysis techniques. Results: 398 medical professionals participated in the study giving a response rate of 18%. 77% of respondents agreed to routinely review patient prescribed codeine. 59% of respondents routinely asked patients about their use of OTC medicines and 50% documented use of OTC codeine in their patients' medical notes. 93% indicated concern about the potential to purchase codeine from multiple sources. 88% implied that patients did not fully understand the risks of taking OTC medicine containing codeine. Only 21% of respondents were confident in identifying codeine dependence without being informed by the patient and 11.4% agreed to having suitable screening methods in practice. 76% indicated that they would like more instruction on prescribing addictive medicines. Conclusion: Policy should examine the need for greater public health awareness on codeine use and should examine the role of OTC and internet sales in the development of dependence. Further consideration should be given to training and support for those who prescribe addictive medicines in practice