Showing papers on "Secondary circulation published in 1985"
TL;DR: In this article, the evolution of an upwelling filament was studied over a 2-week period by using satellite infrared images, and its thermohaline structure was mapped in situ.
Abstract: The evolution of an upwelling filament was studied over a 2-week period by using satellite infrared images, and its thermohaline structure was mapped in situ The surface velocity field consisted of a large meander extending offshore for at least 300 km The northern branch was ∼40 km wide, flowing offshore at a peak velocity of 055 m/s; the southern branch was flowing inshore at 035 m/s The offshore transport was more than 106 m3 s−1, larger than the Ekman transport The meander was unstable to barotropic instabilities at a scale of ∼15 km From a succession of images a surface convergence γ ≈ 8·10−6 s−1 over 20 km was observed near the sharp front limiting the filament to the south The ∼350 m width of the front indicates a separation of scales between the large-scale strain field and the mixed-layer turbulence parameterized with an eddy diffusion coefficient KH ≈ 025 m2 s−1 Thermohaline layers that originated at the convergence near the sharp front suggest a secondary circulation subducting denser waters to the south underneath the lighter northern water
261 citations
TL;DR: In this article, the authors measured primary and secondary flows in a meandering gravel-bed river at low, intermediate and high discharges to confirm the existence of the main and outer bank cells but also indicate that in some bends the main cell does not extend to the inner bank.
Abstract: Natural channels often adopt a meandering course Water flow in meander bends is three-dimensional, consisting of primary velocities which are tangential to the bend, and secondary velocities, which are in the radial plane The pattern of secondary flow strongly affects the distribution of primary velocities This in turn affects the distribution of erosion and deposition in the bend and the way in which the channel shifts and changes shape Measurements of primary and secondary flows in a meandering gravel-bed river1,2 show that, in addition to the widely recognized main secondary circulation driving surface water outwards and bed water inwards, there can be a small cell of reverse rotation at the outer bank Further data have been collected in a sand-bedded river at low, intermediate and high discharges The results confirm the existence of the main and outer bank cells but also indicate that in some bends the main cell does not extend to the inner bank In fact, secondary flow at the inner bank of wide, shallow bends is directed radially outwards over the whole flow depth at all in-channel flows This indicates that some models of bend flow and channel development may be significantly in error
134 citations
TL;DR: In this article, the kinematic and thermodynamic structure of a strong cold front over the Gulf of Alaska has been determined using aircraft, dropsonde, and radiosonde data obtained during the Storm Transfer and Response Experiment.
Abstract: The kinematic and thermodynamic structure of a strong cold front over the Gulf of Alaska has been determined using aircraft, dropsonde, and radiosonde data obtained during the Storm Transfer and Response Experiment. Synoptic-scale analysis using the Sawyer-Eliassen secondary circulation equation shows that friction and diabatic heating, as well as the geostrophic forcing, are important in accounting for the secondary circulation at the front. A fine-scale analysis, with horizontal resolution of 700m and vertical resolution of 100 m, shows strong relative inflow of warm boundary layer air toward the front from the east and a weaker inflow of cold air from the west. Updraught velocities of greater than 6 m s−1 over a 2 km width were measured at 875 mb near the leading edge of the front. the frontogenetical effects of confluence, turbulent mixing, and tilting of isentropic surfaces are evaluated in the region of the front and compared with the results of previous studies. the high resolution of the thermodynamic fields provides new data for comparison with high resolution numerical models.
57 citations
Patent•
26 Sep 1985
TL;DR: In this article, a process for the production of cold with interposed cold reservoir for the supply of ventilating plants or the like with cold water and a plant for the performance of the process is described.
Abstract: The invention relates to a process for the production of cold with interposed cold reservoir for the supply of ventilating plants or the like with cold water and a plant for the performance of the process This process is characterised in that a primary circulation, with a cold reservoir constructed as a water reservoir with partial ice formation, and a secondary circulation, in heat exchange with the first circulation and with at least one heat exchanger on the consumer side, are used a) a water reservoir with an integrated ice reservoir being used, and the heated return water of the primary circulation, introduced into the water reservoir with partial ice formation, flowing through the water reservoir by forced flow via bypasses, and being taken in again from the water reservoir as feed water of the primary circulation, b) the pumps in the primary circulation conducting the low tempered cold water being controlled and switched by the feed and return temperatures, controlled by the external temperature, in the secondary circulation, with simultaneous maximum limiting of the return temperature of the primary circulation, and c) by regulation of the cold water flow in the secondary circulation while maintaining a minimum quantity of circulation to obtain the control parameters for the secondary and primary circulation pumps, the pumps in the secondary circulation being controlled by the differential pressure required for the heat exchanger(s) on the consumer side s
2 citations