title: Assessment of the performance of a turbulence closure model: along the tidally-influenced Kaipara River to the estuary, NZ

authors: Dejeans, Bérengère S.

subjects: turbulence

abstract: The success of many coastal management projects hinges on the ability to predict the dispersal and settling of sediment particles. Hydrodynamic models have enabled the efficient simulation of sediment transport scenarios at large spatial scales and long time scales. However, these models have limited predictive capacity owing to an incomplete understanding of the processes involved. Turbulence has been shown to have a substantial influence on sediment transport by influencing flocculation (i.e. aggregation of particles), hence driving the behaviour of particles (e.g. deposition, erosion, mixing). Turbulence tends to promote aggregation at low shear stresses and cause floc breakups at high shear stresses. However, despite the key role of turbulence in coastal modelling, there is not a unique approach but several methods to describe turbulence, each based on a different combination of assumptions. We present modelling results exploring the performance of one closure scheme implemented in a hydrodynamic and sediment transport model, Delft3D. The assessment of the performance of the model is based on comparisons with measured data collected in the heavily sediment-laden Kaipara river, New Zealand. Data was collected in October 2013 using Lagrangian “flocdrifter” platforms released at multiple locations to capture both hydrodynamic and sediment data. In general the model was found to be able to reproduce the right order of magnitude of dissipation rates. However, turbulence characteristics in some sections of the river, usually in the vicinity of abrupt bends, are relatively poorly reproduced. Future work will aim to use the present model to improve the conceptual understanding of fundamental physical processes, in particular the effect of turbulence on flocculation, and floc formation and breakup in estuarine and riverine systems.

text: Assessment of the performance of a turbulence closure model: along the tidally-influenced Kaipara River to the estuary, NZ The success of many coastal management projects hinges on the ability to predict the dispersal and settling of sediment particles. Hydrodynamic models have enabled the efficient simulation of sediment transport scenarios at large spatial scales and long time scales. However, these models have limited predictive capacity owing to an incomplete understanding of the processes involved. Turbulence has been shown to have a substantial influence on sediment transport by influencing flocculation (i.e. aggregation of particles), hence driving the behaviour of particles (e.g. deposition, erosion, mixing). Turbulence tends to promote aggregation at low shear stresses and cause floc breakups at high shear stresses. However, despite the key role of turbulence in coastal modelling, there is not a unique approach but several methods to describe turbulence, each based on a different combination of assumptions. We present modelling results exploring the performance of one closure scheme implemented in a hydrodynamic and sediment transport model, Delft3D. The assessment of the performance of the model is based on comparisons with measured data collected in the heavily sediment-laden Kaipara river, New Zealand. Data was collected in October 2013 using Lagrangian “flocdrifter” platforms released at multiple locations to capture both hydrodynamic and sediment data. In general the model was found to be able to reproduce the right order of magnitude of dissipation rates. However, turbulence characteristics in some sections of the river, usually in the vicinity of abrupt bends, are relatively poorly reproduced. Future work will aim to use the present model to improve the conceptual understanding of fundamental physical processes, in particular the effect of turbulence on flocculation, and floc formation and breakup in estuarine and riverine systems.

year: 2017

title: Has the deceived businessman been deceiving philosophers?

authors: Weijers, Dan M.

abstract: In the deceived businessman thought experiment, we are asked to imagine the lives of two businessmen, equal in net pleasant experiences, but unequal in the amount of deception. Both lives are experienced as equally happy from the inside, but one is deceived about many important things, while the other isn’t. When comparing these two lives, people usually report that the non-deceived life is preferable to the deceived life. Philosophers working on wellbeing have used this result to discredit experiential accounts of wellbeing, especially prudential hedonism. I argue that two structural problems with the thought experiment preclude it from being a reliable source of evidence for drawing conclusions about wellbeing, including discrediting prudential hedonism. If I’m right that these structural problems mean the deceived businessman thought experiment should not be used when arguing about wellbeing, then several other influential thought experiments with the same structural problem might also be under threat.

text: Has the deceived businessman been deceiving philosophers? In the deceived businessman thought experiment, we are asked to imagine the lives of two businessmen, equal in net pleasant experiences, but unequal in the amount of deception. Both lives are experienced as equally happy from the inside, but one is deceived about many important things, while the other isn’t. When comparing these two lives, people usually report that the non-deceived life is preferable to the deceived life. Philosophers working on wellbeing have used this result to discredit experiential accounts of wellbeing, especially prudential hedonism. I argue that two structural problems with the thought experiment preclude it from being a reliable source of evidence for drawing conclusions about wellbeing, including discrediting prudential hedonism. If I’m right that these structural problems mean the deceived businessman thought experiment should not be used when arguing about wellbeing, then several other influential thought experiments with the same structural problem might also be under threat.

year: 2017

title: Bite

authors: Mitchell, Tori

subjects: poetry

abstract: Bite is a collection of blunt confessional poetry draped in honesty, identity, and 21st century feminism, examined through lived experience with eating disorders, sexuality, trauma, disconnect from family and culture, love and loss, and what it means to be a girl growing up. The collection explores these raw concepts with vulnerability, through the eyes of ‘wolf girl’, in hopes that talking loudly about these topics will force the public to challenge the silence and stigma around them.  

This thesis was inspired by Maori Mythology, and all of the Polynesian poets who showed me how important it is for women of colour to share their stories and experiences. It was also influenced by feminist artists Jenny Holzer, Tracey Emin, and Barbara Kruger, whose art embodies the content of these poems in a literal way: freedom of expression, stripped bare and unflinching. The poetry in this collection is confronting, visceral, and filled with bite.

text: Bite Bite is a collection of blunt confessional poetry draped in honesty, identity, and 21st century feminism, examined through lived experience with eating disorders, sexuality, trauma, disconnect from family and culture, love and loss, and what it means to be a girl growing up. The collection explores these raw concepts with vulnerability, through the eyes of ‘wolf girl’, in hopes that talking loudly about these topics will force the public to challenge the silence and stigma around them.  

This thesis was inspired by Maori Mythology, and all of the Polynesian poets who showed me how important it is for women of colour to share their stories and experiences. It was also influenced by feminist artists Jenny Holzer, Tracey Emin, and Barbara Kruger, whose art embodies the content of these poems in a literal way: freedom of expression, stripped bare and unflinching. The poetry in this collection is confronting, visceral, and filled with bite.

year: 2020