Large scale inhomogeneities and mesoscale ocean waves: A single, stable wave field

Horizontally propagating wave solution forms are assumed for mid-ocean mesoscale currents (i.e., those with spatial and temporal cycles of a few hundred kilometers and several months). The wave environment-defined to include the Coriolis parameter, bottom topography, and mean currents-is assumed to be inhomogeneous, but only on much larger scales. Mutual compatibility between these assumptions is derived...

Efficient Coupling of Micro/Macroscale Analyses with Stochastic Variations of Constituent Properties

Full-domain multiscale analyses of unidirectional AS4/H3502 open-hole composite tensile specimens were performed to assess the effect of microscale progressive fiber failures in regions with large stress/strain gradients on macroscale composite strengths. The effect of model discretization at the microscale and macroscale on the calculated composite strengths and analysis times was investigated. Multiple sets of microscale analyses of repeating unit cells, each containing varying numbers of fibers with a distinct statistical distribution of fiber strengths and fiber volume fractions, were used to establish the microscale discretization for use in multiscale calculations. In order to improve computational times, multiscale analyses were performed over a reduced domain of the open-hole specimen. The calculated strengths obtained using reduced domain analyses were comparable to those for full-domain analyses, but at a fraction of the computational cost. Such reduced domain analyses likely are an integral part of efficient adaptive multiscale analyses of large all-composite air vehicles

Efficient Coupling of Micro/Macroscale Analyses with Stochastic Variations of Constituent Properties

Full-domain multiscale analyses of unidirectional AS4/H3502 open-hole composite tensile specimens were performed to assess the effect of microscale progressive fiber failures in regions with large stress/strain gradients on macroscale composite strengths. The effect of model discretization at the microscale and macroscale on the calculated composite strengths and analysis times was investigated. Multiple sets of microscale analyses of repeating unit cells, each containing varying numbers of fibers with a distinct statistical distribution of fiber strengths and fiber volume fractions, were used to establish the microscale discretization for use in multiscale calculations. In order to improve computational times, multiscale analyses were performed over a reduced domain of the open-hole specimen. The calculated strengths obtained using reduced domain analyses were comparable to those for full-domain analyses, but at a fraction of the computational cost. Such reduced domain analyses likely are an integral part of efficient adaptive multiscale analyses of large all-composite air vehicles

On the mean dynamical balances of the Gulf Stream Recirculation Zone

The time mean circulation is analyzed at a site on the southern edge of the Gulf Stream Recirculation Zone (31N, 70W) from data taken in the POLYMODE Local Dynamics Experiment. Additional mean quantities are described from a combination of dynamical assertions and inferences. The mean vorticity balance is examined to infer the mean vertical velocity and eddy relative vorticity flux divergence. The vertical velocity is found to be mostly upward and an order of magnitude larger than the downward surface Ekman pumping. In the mean heat, salt, density, and potential vorticity budgets, the mean advections of these quantities are nonzero, and substantial eddy flux divergences are again required for balance. These are inferred to be primarily associated with mesoscale eddies. The corresponding horizontal eddy diffusivities for these quantities are large (≈108 cm2 s−1 over an extensive depth range, from the surface to at least 4000 m. An assessment is also made of the likelihood of a homogeneous potential vorticity layer in the Recirculation Zone. From our estimates of the local potential vorticity gradients, there is no clearly indicated zero gradient layer, and the qualitative features of our local estimates are consistent with the larger-scale analysis of McDowell et al. (1983

Sky localization of complete inspiral-merger-ringdown signals for nonspinning massive black hole binaries

We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, combining for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA response. We consider an ensemble of systems near the peak of LISA's sensitivity band, with total rest mass of 2\times10^6 M\odot, a redshift of z = 1, and randomly chosen orientations and sky positions. We find median sky localization errors of approximately \sim3 arcminutes. This is comparable to the field of view of powerful electromagnetic telescopes, such as the James Webb Space Telescope, that could be used to search for electromagnetic signals associated with merging massive black holes. We investigate the way in which parameter errors decrease with measurement time, focusing specifically on the additional information provided during the merger-ringdown segment of the signal. We find that this information improves all parameter estimates directly, rather than through diminishing correlations with any subset of well- determined parameters. Although we have employed the baseline LISA design for this study, many of our conclusions regarding the information provided by mergers will be applicable to alternative mission designs as well.Comment: 9 pages, 5 figures, submitted to Phys. Rev.