Tidal energy researchers and developers use experimental testing of scaled devices as a method of evaluating device performance. Much of the focus to date has been on horizontal axis turbines. This study is focused on a novel vertical axis turbine which incorporates variable-pitch blades and a flow accelerator. The research involves laboratory testing of scale model devices in a recirculating flume. Computational fluid dynamic modelling is used to reproduce the measured flow data to investigate disparities in experimental data. The results show that the device is capable of achieving localised flow acceleration of up to a factor of 2 above the freestream velocity and achieved a mechanical power efficiency of 40%.

The current study investigated a particular aspect shared by a number of theories of depression under the common heading of object relations theory (ORT), namely that depression is associated with a continuing pattern of poor attachment that is laid out in childhood and continues into adulthood. The study examined the relationship between attachment (both parental and peer) and depressive symptoms in young adults (N ϭ 85) of Northern Ireland. Results provided support for the continuity of perceptions of attachment styles across the life span and revealed that perceptions of early attachment experiences, as well as continuing peer attachment styles, appeared to be predictive of current depressive symptoms. More specifically, the analyses revealed a statistically significant positive correlation between perceived quality of current peer attachment and symptoms of depression, as well as a statistically significant negative correlation between self-reported childhood maternal care and symptoms of depression. However, other self-reported measures of childhood attachment were not found to be significant predictors of depressive symptoms (i.e., paternal care, maternal overprotection, paternal overprotection). Taken together, the findings lend some support for this important element of a number of object relations theories, as they pertain to depression. Further empirical research is indicated.

This paper presents the numerical modelling of a novel vertical axis tidal turbine that incorporates localised flow acceleration and variable-pitch blades. The focus is to develop a computational fluid dynamics model of a 1:20 scale model of the device using ANSYS® Fluent®. A nested sliding mesh technique is presented, using an outer sliding mesh to model the turbine and additional inner sliding meshes used for each of the six blades. The turbine sliding mesh is embedded in an outer static domain which includes the flow accelerating bluff body. Modelled power performance and velocity data are compared with experimental results obtained from scale model tests in a recirculating flume. The predicted power curves show general agreement with the measured data; the relative difference in maximum performance coefficient for example, is just 5.7 %. The model also accurately reproduces measured flows downstream of the turbine. The verified and experimentally validated model is subsequently used to investigate the effects of the variable-pitching and number of blades on device performance.

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