Separation of turbulent, incompressible flow from a curved, backward-facing step

October 1966Includes bibliographical referencesAn experimental investigation of turbulent, incompressible flow separation over curved and sharp, backward-facing steps is presented with results for various step heights. Mean velocities in the separating boundary layer as well as the downstream shear layer were recorded. The static pressure in the separated region was determined with a spherical probe. With the curved step, the boundary layer separated at approximately 28 degrees: the reattachment lengths were somewhat less and the base pressures slightly higher than those with the sharp step.Research carried out under Bureau of Ships General Hydromechanics Research Program, administered by the David Taylor Model Basin contract S-R009 01 01 Nonr 1841(91

CHOICE: Choosing Health Options In Chronic Care Emergencies

Background Over 70% of the health-care budget in England is spent on the care of people with long-term conditions (LTCs), and a major cost component is unscheduled health care. Psychological morbidity is high in people with LTCs and is associated with a range of adverse outcomes, including increased mortality, poorer physical health outcomes, increased health costs and service utilisation. Objectives The aim of this programme of research was to examine the relationship between psychological morbidity and use of unscheduled care in people with LTCs, and to develop a psychosocial intervention that would have the potential to reduce unscheduled care use. We focused largely on emergency hospital admissions (EHAs) and attendances at emergency departments (EDs). Design A three-phase mixed-methods study. Research methods included systematic reviews; a longitudinal prospective cohort study in primary care to identify people with LTCs at risk of EHA or ED admission; a replication study in primary care using routinely collected data; an exploratory and feasibility cluster randomised controlled trial in primary care; and qualitative studies to identify personal reasons for the use of unscheduled care and factors in routine consultations in primary care that may influence health-care use. People with lived experience of LTCs worked closely with the research team. Setting Primary care. Manchester and London. Participants People aged ≥ 18 years with at least one of four common LTCs: asthma, coronary heart disease, chronic obstructive pulmonary disease (COPD) and diabetes. Participants also included health-care staff. Results Evidence synthesis suggested that depression, but not anxiety, is a predictor of use of unscheduled care in patients with LTCs, and low-intensity complex interventions reduce unscheduled care use in people with asthma and COPD. The results of the prospective study were that depression, not having a partner and life stressors, in addition to prior use of unscheduled care, severity of illness and multimorbidity, were independent predictors of EHA and ED admission. Approximately half of the cost of health care for people with LTCs was accounted for by use of unscheduled care. The results of the replication study, carried out in London, broadly supported our findings for risk of ED attendances, but not EHAs. This was most likely due to low rates of detection of depression in general practitioner (GP) data sets. Qualitative work showed that patients were reluctant to use unscheduled care, deciding to do so when they perceived a serious and urgent need for care, and following previous experience that unscheduled care had successfully and unquestioningly met similar needs in the past. In general, emergency and primary care doctors did not regard unscheduled care as problematic. We found there are missed opportunities to identify and discuss psychosocial issues during routine consultations in primary care due to the ‘overmechanisation’ of routine health-care reviews. The feasibility trial examined two levels of an intervention for people with COPD: we tried to improve the way in which practices manage patients with COPD and developed a targeted psychosocial treatment for patients at risk of using unscheduled care. The former had low acceptability, whereas the latter had high acceptability. Exploratory health economic analyses suggested that the practice-level intervention would be unlikely to be cost-effective, limiting the value of detailed health economic modelling. Limitations The findings of this programme may not apply to all people with LTCs. It was conducted in an area of high social deprivation, which may limit the generalisability to more affluent areas. The response rate to the prospective longitudinal study was low. The feasibility trial focused solely on people with COPD. Conclusions Prior use of unscheduled care is the most powerful predictor of unscheduled care use in people with LTCs. However, psychosocial factors, particularly depression, are important additional predictors of use of unscheduled care in patients with LTCs, independent of severity and multimorbidity. Patients and health-care practitioners are unaware that psychosocial factors influence health-care use, and such factors are rarely acknowledged or addressed in consultations or discussions about use of unscheduled care. A targeted patient intervention for people with LTCs and comorbid depression has shown high levels of acceptability when delivered in a primary care context. An intervention at the level of the GP practice showed little evidence of acceptability or cost-effectiveness. Future work The potential benefits of case-finding for depression in patients with LTCs in primary care need to be evaluated, in addition to further evaluation of the targeted patient intervention

Separation of turbulent, incompressible flow from a curved, backward-facing step

October 1966Includes bibliographical referencesAn experimental investigation of turbulent, incompressible flow separation over curved and sharp, backward-facing steps is presented with results for various step heights. Mean velocities in the separating boundary layer as well as the downstream shear layer were recorded. The static pressure in the separated region was determined with a spherical probe. With the curved step, the boundary layer separated at approximately 28 degrees: the reattachment lengths were somewhat less and the base pressures slightly higher than those with the sharp step.Research carried out under Bureau of Ships General Hydromechanics Research Program, administered by the David Taylor Model Basin contract S-R009 01 01 Nonr 1841(91