A CFD validation workshop for synthetic jets and turbulent separation control (CFD-VAL2004) was held in Williamsburg, Virginia in March 2004. Three cases were investigated: synthetic jet into quiescent air, synthetic jet into a turbulent boundary layer cross ow, and ow o ver a hump model with no-ow-control, steady suction, and oscillatory control. This paper is a summary of the CFD results from the workshop. Although some detailed results are shown, mostly a broad viewpoint i s t a k en, and the CFD stateof-the-art for predicting these types of ows is evaluated from a general point of view. Overall, for synthetic jets, CFD can only qualitatively predict the ow p h ysics, but there is some uncertainty regarding how to best model the unsteady boundary conditions from the experiment consistently. As a result, there is wide variation among CFD results. For the hump ow, CFD as a whole is capable of predicting many of the particulars of this ow provided that tunnel blockage is accounted for, but the length of the separated region compared to experimental results is consistently overpredicted.

A computational-fluid-dynamics (CFD) validation workshop for synthetic jets and turbulent separation control (CFDVAL2004) was held in Williamsburg, Virginia, in March 2004. Three cases were investigated: a synthetic jet into quiescent air, a synthetic jet into a turbulent boundary-layer crossflow, and the flow over a hump model with no-flow-control, steady suction, and oscillatory control. This is a summary of the CFD results from the workshop. Although some detailed results are shown, the CFD state of the art for predicting these types of flows is mostly evaluated from a general point of view. Overall, for synthetic jets, CFD can only qualitatively predict the flow physics, but there is some uncertainty regarding how to best model the unsteady boundary conditions from the experiment consistently. As a result, there is wide variation among CFD results. For the hump flow, CFD is capable of predicting many of the particulars of this flow, provided that it accounts for tunnel blockage, but it consistently overpredicts the length of the separated region compared to the experimental results.

Claws are involved in a number of behaviours including locomotion and prey capture, and as a result animals evolve claw morphologies that enable these functions. Past authors have found geometry of the keratinous sheath of the claw to correlate with mode of life for extant birds and squamates; this relationship has frequently been cited to infer lifestyles for Mesozoic theropods including Archaeopteryx. However, claw sheaths rarely fossilise and are prone to deformation; past inferences are thus compromised. As the ungual phalanx within the claw is relatively resistant to deformation and more commonly preserved in the fossil record, geometry of this bone would provide a more useful metric for paleontological analysis. In this study, ungual bones of 108 birds and 5 squamates were imaged using X-ray techniques and a relationship was found between curvatures of the ungual bone within the claw of pedal digit III and four modes of life; ground-dwelling, perching, predatory, and scansorial; using linear discriminant analysis with Kappa equal to 0.69. Our model predicts arboreal lifestyles for certain key taxa Archaeopteryx and Microraptor and a predatory ecology for Confuciusornis. These findings demonstrate the utility of our model in answering questions of palaeoecology, the theropod-bird transition, and the evolution of avian flight. 2/30

No abstract

Preliminary analysis of near-bottom, high-resolution DSL-120 sidescan and bathymetric data from the median valley in the TAG (Trans-Atlantic Geotraverse) segment near 26°N on the Mid-Atl antic Ridge, and Argo-Il photography from the associated actively venting hydrothermal mound, allows us to evaluate the structural, volcanic, and hydrothermal processes occurring in this area, and to provide baseline constraints on the pre-drilling status of the morphology of the mound and the distribution of venting. These data were collected just 2 months before ODP drilling of the active TAG mound, one of the largest volcanichosted, mid-ocean ridge hydrothermal deposits yet discovered. Sharp discontinuities and strong asymmetry in the morphology and age distribution about the spreading axis suggest a recent episode of preferential accretion of crust to the east. Such episodes have likely contributed to the long-term spreading asymmetry (13 mm/yr to the east, 11 mm/yr to the west) of the TAG segment. The active mound lies within the intersection of a zone of actively developing ridge-parallel (north-northeast) fissures and a series of pre-existing obliquely oriented (east-northeast) faults. The east-northeast faults are not continuous with faults previously described from the upper rift valley walls. This intersecting fault pattern may be important in localizing hydrothermal activity. Contemporaneous tectonic deformation and hydrothermal deposition continue to modify the three-dimensional structure and hydrogeology of the active TAG mound.

No abstract

No abstract

The paper describes the efforts at NASA