Steep waves in free-surface flow past narrow topography

In this work, we compute steep forced solitary wave solutions for the problem of free-surface flow over a localised topographic disturbance in an otherwise flat horizontal channel bottom. A single forced solitary wave and a double-crested forced solitary wave solution are shown to exist, both of which approach the Stokes limiting configuration of an included angle of 120∘ and a stagnation point at the wave crests. The solution space for the topographically forced problem is compared to that found in Wade et al. [“On the free-surface flow of very steep forced solitary waves,” J. Fluid Mech. 739, 1–21 (2014)], who considered forcing due to a localised distribution of pressure applied to the free surface. The main feature that differentiates the two types of forcing is an additional solution that exists in the pressure-forced problem, a steep wave with a cusp at a single wave crest. Our numerical results suggest that this cusped-wave solution does not exist in the topographically forced problem

Turbulent swirling flow in a model of a uniflow-scavenged two-stroke engine

ISSN:0723-4864ISSN:1432-111

Traumatic Brain Injury: Nuclear Medicine Neuroimaging

This chapter provides an up-to-date review of nuclear medicine neuroimaging in traumatic brain injury (TBI). 18F-FDG PET will remain a valuable tool in researching complex mechanisms associated with early metabolic dysfunction in TBI. Although evidence-based imaging studies are needed, 18F-FDG PET in the TBI acute phase appeared to be more useful in those patients in whom structural neuroimages fail to show abnormalities explaining their neurological state. 15O2-PET is also a solid technique for research in acute TBI, but in contrast to 18F-FDG PET it is not widely available due to its high cost. In the chronic TBI phase, most 18F-FDG PET studies converge to identify a diffuse cortical–subcortical hypometabolism involving key regions for cognitive function. Recent studies suggest the usefulness of 18F-FDG PET for the evaluation of therapeutic interventions in chronic TBI patients with cognitive deficits. In recent years, interest in studying cell-specific processes is growing. The use of radioligands as markers of neuroinflammation could become attractive for detecting secondary damage and serve for the evaluation of different therapeutic approaches. SPECT advances also make this technique a valid alternative for the study of TBI