scholarly journals Time dependent flow of Atlantic Water on the continental slope of the Beaufort Sea based on moorings

Author(s):  
Jianqiang Li ◽  
Peigen Lin ◽  
Robert S. Pickart ◽  
Xiao‐Yi Yang
2016 ◽  
Vol 29 (12) ◽  
pp. 4509-4523 ◽  
Author(s):  
Sergei Kirillov ◽  
Igor Dmitrenko ◽  
Bruno Tremblay ◽  
Yves Gratton ◽  
David Barber ◽  
...  

Abstract The role of wind forcing on the vertical displacement of the −1°C isotherm and 33.8 isohaline depths was examined based on snapshots of historical (1950–2013) temperature and salinity profiles along the Mackenzie continental slope (Beaufort Sea). It is found that upwelling is correlated with along-slope northeast (T59°) winds during both ice-free and ice-covered conditions, although the wind impact is more efficient during the ice-free season. One of the most important factors responsible for vertical displacements of isopycnals is sustained wind forcing that can last for several weeks and even longer. It accounts for 14%–55% of total variance in isotherm/isohaline depths, although these numbers might be underestimated. The upwelling and downwelling events are discussed in the context of the interplay between two regional centers of action—the Beaufort high and Aleutian low—that control the wind pattern over the southern Beaufort Sea. The probability of upwelling-favorable wind occurrence is closely related to the sea level pressure difference between these two centers, as well as their geographical positions. The combined effect of both centers expressed as the SLP differences is highly correlated (0.68/0.66 for summer/winter) with occurrences of extreme upwelling-favorable northeast (NE) winds over the Mackenzie slope, although the Beaufort high plays a more important role. The authors also diagnosed the predominant upwelling-favorable conditions over the Mackenzie slope in the recent decade associated with the summertime amplification of the Beaufort high. The upwelling-favorable NE wind occurrences also demonstrate the significant but low (−0.30) correlation with Arctic Oscillation (AO) during both summer and winter seasons, whereas the high correlation with North Pacific index (NPI; −0.52) is obtained only for the ice-covered period.


2004 ◽  
Vol 127 (3) ◽  
pp. 400-415 ◽  
Author(s):  
Amador M. Guzmán ◽  
Rodrigo A. Escobar ◽  
Cristina H. Amon

Computational investigations of flow mixing and oxygen transfer characteristics in an intravenous membrane oxygenator (IMO) are performed by direct numerical simulations of the conservation of mass, momentum, and species equations. Three-dimensional computational models are developed to investigate flow-mixing and oxygen-transfer characteristics for stationary and pulsating balloons, using the spectral element method. For a stationary balloon, the effect of the fiber placement within the fiber bundle and the number of fiber rings is investigated. In a pulsating balloon, the flow mixing characteristics are determined and the oxygen transfer rate is evaluated. For a stationary balloon, numerical simulations show two well-defined flow patterns that depend on the region of the IMO device. Successive increases of the Reynolds number raise the longitudinal velocity without creating secondary flow. This characteristic is not affected by staggered or non-staggered fiber placement within the fiber bundle. For a pulsating balloon, the flow mixing is enhanced by generating a three-dimensional time-dependent flow characterized by oscillatory radial, pulsatile longitudinal, and both oscillatory and random tangential velocities. This three-dimensional flow increases the flow mixing due to an active time-dependent secondary flow, particularly around the fibers. Analytical models show the fiber bundle placement effect on the pressure gradient and flow pattern. The oxygen transport from the fiber surface to the mean flow is due to a dominant radial diffusion mechanism, for the stationary balloon. The oxygen transfer rate reaches an asymptotic behavior at relatively low Reynolds numbers. For a pulsating balloon, the time-dependent oxygen-concentration field resembles the oscillatory and wavy nature of the time-dependent flow. Sherwood number evaluations demonstrate that balloon pulsations enhance the oxygen transfer rate, even for smaller flow rates.


Author(s):  
Karsten Hanser ◽  
Ole Klein ◽  
Bastian Rieck ◽  
Bettina Wiebe ◽  
Tobias Selz ◽  
...  

2011 ◽  
Vol 25 (19) ◽  
pp. 2533-2542
Author(s):  
T. HAYAT ◽  
S. N. NEOSSI NGUETCHUE ◽  
F. M. MAHOMED

This investigation deals with the time-dependent flow of an incompressible viscous fluid bounded by an infinite plate. The fluid is electrically conducting under the influence of a transverse magnetic field. The plate moves with a time dependent velocity in its own plane. Both fluid and plate exhibit rigid body rotation with a constant angular velocity. The solutions for arbitrary velocity and magnetic field is presented through similarity and numerical approaches. It is found that rotation induces oscillations in the flow.


Sign in / Sign up

Export Citation Format

Share Document