A new model of turbulent flow and of two-temperature heat transfer in a highly porous medium is evaluated numerically for a layer of regular packed particles. The layer can have heat exchange from the defining surfaces. The commonly used models of variable morphology functions for porosity and specific surface were used to obtain comparisons with other works in a relatively high Reynolds number range. A few outstanding features of the closure models for additional integral terms in equations of flow and heat transfer are advanced. Closures were developed for capillary and globular medium morphology models. It is shown that the approach taken to close the integral resistance terms in the momentum equation for a regular structure can be obtained in a way that allows the second order terms for laminar and turbulent regimes to naturally occur. These terms are taken to be close to the Darcy term or Forchheimer terms for different flow velocities. The two-temperature model was compared with a one-temperature model using thermal diffusivity coefficients and effective coefficients from various authors. Calculated pressure drop along a layer showed very good agreement with experiment for a porous structure of spherical beads. A simplified model with constant coefficients was compared with analytical solutions.
We calculate the depth of winter convection in the Lofoten Basin in the Norwegian Sea using the oceanic reanalysis GLORYS12V1 data for the period 1993 to 2018. Two independent methods are used to estimate the depth of the mixed layer depth (MLD). We call the first method as the Kara method and the second one as the Montegut method. We build the monthly average maps of the MLD for the period from
December to April. The maximum values of the MLD are observed in the area of the Lofoten Vortex. The MLD is maximal in March reaching 400-500 m, and 200 to 400 m in the other months. The MLD tends to increase in the northern and northwestern parts of the study area. We show the estimates of the MLD obtained by the Montegut method to be underestimated in comparison with the estimates by the Kara method. We estimate coefficients of the linear trend for monthly averaged MLD values from December to April for the period 1993 to 2018. We demonstrate in the interannual variability that the winter convection decreases in December, January, and February at the end of the study period, but it increases in March and April. This means a shift in the periods of maximum development of winter convection to a later date. This shift may be due to the processes of global warming. There is a significant intra-monthly variability when the values
of the MLD can differ by 1.5-2 times during a month. Since the methods by Kara and Montegut are based both on empirical criteria, the estimates of MLD in the Lofoten Basin differ from each other. However, the empirical approaches for MLD estimates make it impossible to determine the advantages of one method relative to another
The Lofoten Basin in the Norwegian Sea is the area where the warm Atlantic Water exhibits the greatest loss of heat than anywhere else in the Nordic Seas. It is called a "hot spot" of the Nordic Seas because of its high intense mesoscale eddy activity. Mesoscale eddies contribute significantly to the total oceanic heat and salt transport by advective trapping, stirring and mixing, and thus play an important role in the heat and salt balance of the region. A purpose of this study is to examine seasonal variability of mesoscale eddies in the Lofoten Basin using satellite altimetry data and GLORYS reanalysis. Satellite altimetry is used to track individual eddies, and co-located vertical profiles based on GLORYS data allow to study thermohaline characteristics inside the eddy cores. We analyze numbers of cyclonic and anticyclonic eddies in the Lofoten Basin using an eddy identification and tracking algorithm and demonstrate that the occurrences of eddies depend strongly on the season. We analyze seasonal variability of temperature, salinity, and potential density anomalies in zonal sections across the core of the Lofoten Vortex and explore spatial variability of thermohaline characteristics of mesoscale eddies at the depth of 450 m in different seasons.
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