Saltwater Flow Research Articles

Spatio-Temporal Patterns of Saltwater Intrusion in A Narrow Meandering Channel

Saltwater intrusion has become a crucial issue for water resources management across the globe. Consequently, this issue leads to problems such as encroachment on water intake zone, loss of freshwater vegetation and also disturbance to aquatic life habitat. Undeniably climate change increases the saline water flow into the river system. The meandering rivers are common, and the hydraulics is more complex than straight rivers. An experimental hydraulic investigation was carried out in the Universiti Teknologi Malaysia to elucidate the hydrodynamic interactions between saline water and freshwater in a narrow meandering channel. The spatio-temporal salinity profiles along the river are discussed in this paper. The findings prevailed a typical characteristic of a salt-wedge estuary and indicated the processes of estuarine mixing. As the saltwater flows upstream, the salinity level drops due to the dilution process. Salinity levels and densimetric Froude number were mainly driven by freshwater discharge in the channel. A variation of dilution rate in a narrow meandering channel were up to 78.9% due to strong velocity forces produced by a high freshwater discharge. Furthermore, the flow resistance induced by the channel boundaries and meander planform itself influenced the salinity intrusion profiles along the channel.

Hydrogeological environments and radon activities of saline geothermal hot spring sites located along eastern and western coastlines of southern Thailand

Hydrogeological settings and natural radionuclides of saline geothermal fields along the coastlines of the Gulf of Thailand and Andaman Sea in Southern Thailand are currently not fully understood. Six saline geothermal springs have been discovered in Surat Thani Province (Southern Thailand's east coast); SR2, SR3, and SR7 sites; Krabi Province (Southern Thailand's west coast); KB2, KB3, and KB4 sites. Based on total dissolved solid contents, we divided the saline geothermal springs into three categories: a) slightly saline geothermal spring had only SR7 (1828 mg/L), b) moderately saline geothermal spring consisted of SR2 (10,196 mg/L) and KB3 (3448 mg/L), and c) very saline geothermal spring comprised SR3 (11,856 mg/L), KB2 (17,014 mg/L) and KB4 (18,070 mg/L). The major ions in the saline geothermal groundwater represent decreasing trends with the distance from the coastline. Stable isotope signatures (δ18O and δ2H) relative to the VSMOW plotted in comparison with the global meteoric water line and local meteoric water line are presumably of meteoric origin and influenced by seawater/brackish water. However, the SR7 and KB3 sites indicated that the isotopic signatures were mainly recharged by rainwater. Significantly, the Na-K-Ca-Mg geothermometer can reasonably estimate the reservoir temperatures for the five saline geothermal springs to be in the range of 120 °C (KB3) to 169 °C (SR2). While the SR7, the silica-quartz geothermometer is proposed of approximately 115 °C. However, the silica-chalcedony and other cation geothermometers fail to estimate suitable reservoir temperatures. On the other hand, the radon concentrations in the saline geothermal groundwater along the Gulf of Thailand and Andaman Sea were assessed by RAD7-H2O, which varied from 18.64 ± 0.96 kBq/m3 (KB2; Andaman Sea side) to 8507.48 ± 1.06 kBq/m3 (SR7; Gulf of Thailand side). A comparison of radon activity with the saltwater intrusion showed that the saline geothermal groundwater on the Gulf of Thailand side had higher levels than that at the Andaman Sea side. The deposition of Quaternary sediments combined with significant saltwater inflow enriched with radon resulted from the decay of uranium from both non-marine and coastal deposits related to granitic mountain weathering along the Gulf of Thailand. Radon concentrations in the geothermal groundwater were highly influenced by the local geological environment and coastal sediments.

Responses of Four Peatland Emergent Macrophytes to Salinity and Short Salinity Pulses

Sea-level rise intensifies saltwater influx into coastal wetlands causing osmotic stress and probably changing vegetation composition. To determine especially the impact of salinity pulses that occur during flooding events, Typha latifolia, Carex acutiformis, Schoenoplectus tabernaemontani and Phragmites australis were exposed to different salinity regimes consisting of control (permanently freshwater and permanently brackish water) and alternating freshwater and brackish water with different exposure durations (2 days brackish – 2 days fresh; 4 days brackish – 4 days fresh; 2 days brackish – 4 days fresh). Plant height, leaf area, chlorophyll fluorescence, root:shoot ratio and photosynthetic pigments were measured. Salinity suppressed the growth of T. latifolia resulting in shorter height, smaller mean leaf area and higher root:shoot ratio. Carex acutiformis had smaller mean leaf area and higher root:shoot ratio. Photosynthetic pigment and chlorophyll fluorescence of both species were not affected. Shorter but frequent salinity pulses (alternate 2 days brackish – 2 days freshwater, and 2 days brackish – 4 days freshwater) decreased the leaf area of T. latifolia while C. acutiformis was not affected. Salinity and salinity pulses did not affect the height and root:shoot ratio of P. australis and S. tabernaemontani. Phragmites australis showed signs of successful acclimation through decreased chlorophyll a:carotenoid ratio and high fluorescence Δyield at low and high irradiance. Our results imply that with increasing seawater influx into coastal peatlands, T. latifolia and C. acutiformis may experience growth retardation or may even be replaced by S. tabernaemontani or P. australis since they are more resilient against salinity and frequent salinity pulses.

The Influence of Water Flow Characteristics on the Physical and Mechanical Qualities of Underwater Wet Welded A36 Marine Steel Plate

Underwater welding has proven to be a successful method of joining two similar or dissimilar metals and takes place underwater. This technique is frequently used for maintenance purposes, such as repairing piping systems, ships, and other marine structures. This study investigates the effect of different water flow types on an underwater weld’s physical and mechanical properties of welded bead on the A36 steel plate. The SMAW method with an E7018 electrode is used for welding A36 steel in saltwater. In this simulation, underwater welding is performed using three types of flow (without flow, non-uniform flow with a baffle plate, and non-uniform flow without a baffle plate) to compare metallography, hardness, tensile, impact, and bending testing results. The findings revealed that the saltwater flow caused more porosity defects. Moreover, the highest penetration depth was observed in specimens with the non-uniform flow with a baffle plate. The heat energy is concentrated due to droplets accumulating in the weld area. The microstructure of welding metals such as acicular ferrite and ferrite with the second phase grows as the water flow becomes non-uniform. Furthermore, as the rate and variability of the water flow increased, the value of the mechanical properties of the specimens increased relatively.

Impact of Coastal Marsh Eco‐Geomorphologic Change on Saltwater Intrusion Under Future Sea Level Rise

AbstractCoastal saltwater intrusion (SWI) is one key factor that affects the hydrology, ecology, and biogeochemistry of coastal ecosystems. Future climate change, especially intensified sea level rise (SLR), is expected to trigger SWI to encroach on coastal freshwater aquifers more intensively. Numerous studies have investigated decadal/century scale SWI under SLR by assuming a static coastal landscape topography. However, coastal landscapes are highly dynamic in response to SLR, and the impact of coastal landscape evolution on SWI has received very little attention. Thus, this study used a coastal marsh landscape as an example and investigated how coastal marsh evolution affects future SWI with a physically‐based coastal hydro‐eco‐geomorphologic model, Advanced Terrestrial Simulator. Our numerical experiments showed that it is very likely that the marsh elevation increases with future SLR due to sediment deposition, and a depression zone is formed due to different marsh accretion rates between the ocean boundary and the inland. We found that marsh accretion may significantly reduce the surface saltwater inflow at the ocean boundary, and the evolved topographic depression zone may prolong the residence time of surface ponded saltwater, affecting subsurface salinity distribution differently. We also predicted that marshlands may become more sensitive to upland freshwater supply under future SLR, compared with previous predictions without marsh evolution. This study demonstrates the importance of coastal evolution to coastal freshwater‐saltwater interaction. The eco‐geomorphologic effect may not be ignored when evaluating coastal SWI under SLR at decadal or century scales.

Climate change in the Baltic Sea region: a summary

Abstract. Based on the Baltic Earth Assessment Reports of this thematic issue in Earth System Dynamics and recent peer-reviewed literature, current knowledge of the effects of global warming on past and future changes in climate of the Baltic Sea region is summarised and assessed. The study is an update of the Second Assessment of Climate Change (BACC II) published in 2015 and focuses on the atmosphere, land, cryosphere, ocean, sediments, and the terrestrial and marine biosphere. Based on the summaries of the recent knowledge gained in palaeo-, historical, and future regional climate research, we find that the main conclusions from earlier assessments still remain valid. However, new long-term, homogenous observational records, for example, for Scandinavian glacier inventories, sea-level-driven saltwater inflows, so-called Major Baltic Inflows, and phytoplankton species distribution, and new scenario simulations with improved models, for example, for glaciers, lake ice, and marine food web, have become available. In many cases, uncertainties can now be better estimated than before because more models were included in the ensembles, especially for the Baltic Sea. With the help of coupled models, feedbacks between several components of the Earth system have been studied, and multiple driver studies were performed, e.g. projections of the food web that include fisheries, eutrophication, and climate change. New datasets and projections have led to a revised understanding of changes in some variables such as salinity. Furthermore, it has become evident that natural variability, in particular for the ocean on multidecadal timescales, is greater than previously estimated, challenging our ability to detect observed and projected changes in climate. In this context, the first palaeoclimate simulations regionalised for the Baltic Sea region are instructive. Hence, estimated uncertainties for the projections of many variables increased. In addition to the well-known influence of the North Atlantic Oscillation, it was found that also other low-frequency modes of internal variability, such as the Atlantic Multidecadal Variability, have profound effects on the climate of the Baltic Sea region. Challenges were also identified, such as the systematic discrepancy between future cloudiness trends in global and regional models and the difficulty of confidently attributing large observed changes in marine ecosystems to climate change. Finally, we compare our results with other coastal sea assessments, such as the North Sea Region Climate Change Assessment (NOSCCA), and find that the effects of climate change on the Baltic Sea differ from those on the North Sea, since Baltic Sea oceanography and ecosystems are very different from other coastal seas such as the North Sea. While the North Sea dynamics are dominated by tides, the Baltic Sea is characterised by brackish water, a perennial vertical stratification in the southern subbasins, and a seasonal sea ice cover in the northern subbasins.

Greenhouse Desalination by Humidification–Dehumidification Using a Novel Green Packing Material

Humidification–dehumidification (HD) is a non-traditional desalination process in which water evaporates from a saline liquid stream and the vapour condenses into purified water. In nature, seawater is heated by solar radiation and evaporates from the air that moistens it. This is known as the rainy cycle. The artificial version of this cycle is called the HD desalination cycle. The latter has received a lot of attention in recent years, and many researchers have studied the complexities of the technology. In the present work, experimental work with a simple configuration was developed and built, consisting of a humidification column followed by a condenser, in which the humidified air is dehumidified to produce fresh water. A novel and unique packaging material was used in the humidifier, consisting of a cellulose plant grown on the banks of the River Nile. In all previous work, the main problem was the type of packaging material that could ensure intimate contact and uniformity between aqueous flow and airflow. Consequently, this new filler material proved extremely suitable in terms of hydrophilicity and interconnectivity. Several variables, including the packing mass of each stage, the number of stages, the flow of air and saltwater, the concentration of saltwater, and the inlet temperature of saltwater and condensation temperature, were examined to determine their influence on the production of fresh water and its salinity. The best results arrived at in this study were wet packing conditions, 0.5 m/s air flowrate, 26 g packing for each of the 6-stage columns, and 500 mL/min water flow rate at 70 °C. It was found that this present setup, which can be coupled with solar heating to make the greenhouse desalination process cost-effective, could produce a high production of fresh water and be competitive compared with other commercial applications.

The Analytical Solution Via Cole-Hopf Transformation of the Unsteady MHD Equations of Salt Water Flow Subjected to Multiple Transport Effects

The Analytical Solution Via Cole-Hopf Transformation of the Unsteady MHD Equations of Salt Water Flow Subjected to Multiple Transport Effects

Intermediate plumes of low oxygen in the southeastern Baltic Sea

Closely spaced CTDO profiling on the pathway of saltwater flow in the southeastern Baltic Sea in August and December 2019 revealed low oxygen intermediate layers-plumes with dissolved oxygen concentration (DOC) less than 2 mg/l under the upper boundary of permanent halocline. At the same time, DOC in the underlying layers was higher and reached 5.0–5.3 mg/l. In order to test the hypotheses about the origin of the intermediate hypoxic plumes, numerical hydrodynamic modelling was performed for time intervals including the measurement periods. The model was validated against bottom current velocity instrumental measurements by a TCM (Tilt Current Meter) moored on the track of the CTDO profiling. Numerical experiments with Lagrangian particles of neutral buoyancy coupled with the operational circulation model showed that sub-halocline hypoxic intermediate layers in the southern part of the Eastern Gotland Basin and in the Gdańsk Basin could be formed as a result of intrusion into the underlying bottom layer of denser, moderately oxygenated water from the Słupsk Furrow, which replaced the old anoxic and hypoxic water of Gotland and Gdańsk origin. It is assumed that cyclonic eddy activity above the saltwater flow along sloping bottom caused fragmentation of the hypoxic intermediate layer into separate plumes. The hypoxic intermediate layers in the Słupsk Furrow, in accordance with the results of monitoring measurements and modelling the motion of particles of neutral buoyancy, could be formed in the Bornholm Basin and moved eastward over the Słupsk Sill.

Effects of River Partial Penetration on the Occurrence of Riparian Freshwater Lenses: Experimental Investigation

AbstractThis study examines the occurrence of riparian lenses adjacent to partially penetrating, gaining rivers under the controlled conditions of a laboratory sand tank. Laboratory experiments and numerical modeling of the freshwater lens extent are used to provide physical verification (in light of limited examples of well‐characterized field cases) of the analytical methodology, thereby evaluating the underlying assumptions. Parameter calibration and uncertainty analysis are applied to assess both the experimental conditions and the benefit of lens observations in applying the analytical approach. The experimental freshwater lens was reproduced by both analytical and numerical models, with the exception of small mismatches (between analytical results and measured data) in the lens thickness in the near‐river region. These are most likely due to vertical flow effects that arise from the partial river penetration and saltwater inflows to the river bottom, and that are only partly accounted for in the analytical approach. Uncertainty analysis highlighted that accurate lens predictions based on the analytical method requires calibration to direct lens measurements; a similar finding from earlier studies of fully penetrating river conditions. Sensitivity analysis highlighted that the saltwater head boundary, freshwater and saltwater densities, and the aquifer depth below the riverbed (in descending order of sensitivity) are the most important factors in controlling freshwater lens occurrence and saltwater discharge. The results provide the first physical verification of the occurrence of stable riparian lenses adjacent to partially penetrating, gaining rivers, and verify a recent analytical solution for lens extent and saltwater discharge.

Influence of Salt Water Flow on Structures and Diversity of Biofilms Grown on 316L Stainless Steel.

Salt water, in addition to being a naturally corrosive environment, also includes factors such as temperature, pressure, and the presence of the microbial community in the environment that influence degradation processes on metal surfaces. The presence or absence of water flow over the metal surfaces is also an important aspect that influences the corrosion of metals. The objective of this study was to evaluate the presence or absence of salt water flow in the formation of biofilms grown in 316L stainless steel coupons. For this, the 316L stainless steel coupons were exposed in two different microcosms, the first being a system with continuous salt water flow, and the second without salt water flow system. The results of the sequencing of the 16S rDNA genes showed a clear difference in structures and diversity between the evaluated biofilms. There was greater abundance and diversity in the "In Flux" system when compared to the "No Flux" biofilm. The analysis of bacterial diversity showed a predominance of the Gammaproteobacteria class in both systems. However, at lower taxonomic levels, there were considerable differences in representativeness. Representatives of Vibrionales, Alteromonadales, Oceanospirillales, and Flavobacteriales were predominant in "No Flux", whereas in "In Flux" there was a greater representation of Alteromonadales, Rhodobacterales, and Saprospirales. These findings help to understand how the flow of water influences the dynamics of the formation of microbial biofilms on metal surfaces, which will contribute to the choice of strategies used to mitigate microbial biofouling.

Numerical Study of the Process of Salt Water Inflow to the Don Mouth from the Taganrog Bay

Purpose. Numerical study based on the model example is aimed at examining the process of the salt water inflow to the Stary Don sleeve from the Taganrog Bay due to the wind water surge. Methods and Results. Complex mathematical model of the flow and salt distribution in the open riverbed is described. The section of the River Don, consisting of the Stary Don sleeve and a part of the main channel was considered. Salt is delivered through the host reservoir – the Taganrog Bay. The model is described by the system of Saint-Venant equations and the convection-diffusion equation. The problem is solved by the finite-difference methods. The results of the numerically studied influence of the sea surface level in the Taganrog Bay both on the flow nature in the Don Delta area and the degree of salt penetration upstream of the river are obtained. It was numerically established that the flow rate did not significantly affect salt concentration in the Don main channel. Conclusions. The computational experiments showed that the decisive factor in the process of the salt water inflow to the Don Delta from the Taganrog Bay consisted in the sea level significant increase resulting from extreme wind surges; and the preceding runoffs enhanced this effect even greater. The represented model gives an idea of the general trend in the process of the Don Delta possible salinization as a result of the surge phenomena.

Chislennoye issledovaniye protsessa proniknoveniya solenykh vod iz Taganrogskogo zaliva v ust'ye Dona

Purpose. Numerical study based on the model example is aimed at examining the process of the salt water inflow to the Stary Don sleeve from the Taganrog Bay due to the wind water surge. Methods and Results. Complex mathematical model of the flow and salt distribution in the open riverbed is described. The section of the River Don, consisting of the Stary Don sleeve and a part of the main channel was considered. Salt is delivered through the host reservoir – the Taganrog Bay. The model is described by the system of Saint-Venant equations and the convection-diffusion equation. The problem is solved by the finite-difference methods. The results of the numerically studied influence of the sea surface level in the Taganrog Bay both on the flow nature in the Don Delta area and the degree of salt penetration upstream of the river are obtained. It was numerically established that the flow rate did not significantly affect salt concentration in the Don main channel. Conclusions. The computational experiments showed that the decisive factor in the process of the salt water inflow to the Don Delta from the Taganrog Bay consisted in the sea level significant increase resulting from extreme wind surges; and the preceding runoffs enhanced this effect even greater. The represented model gives an idea of the general trend in the process of the Don Delta possible salinization as a result of the surge phenomena

ON TWO MODELS RELATED TO THE FLOODING AND DEPOSITION OF THE DON DELTA

The results of modeling changes in the water surface level in the eastern part of the Taganrog Bay and the main Don branches in its delta area are presented. A numerical study of the process of saltwater inflow from the Taganrog Bay to the Don delta has been carried out. The hydrodynamics in the Taganrog Bay, as well as the saltwater transport process, are specified using the corresponding two-layer models. A system of Don arms is presented in the form of a graph, the edges of which correspond to open channels, and the vertices correspond to branching points and end nodes. The flow in the main Don branches is described by the Saint-Venant equation. It is assumed that there is no distributed lateral inflow, and the channel cross-section has a parabolic profile. Saltwater inflow into the arms is described by a one-dimensional transport equation. Boundary conditions are specified for each sleeve. At the branching nodes, conditions are set for the equality of the water levels, as well as the equality of the inflowing and outflowing discharges. The description of the algorithm of the process of flooding/drainage of the Don delta area is given. Considering the values of the depths at the nodes of the flat grid, the cells located in water or on land are determined. A logical array characterizing the type of cells (“water”, “land”) sets the configuration of the entire computational domain. Comparison of the calculation results with the observed values of salinity and water level is carried out.

A Double-Phase High-Frequency Traveling Magnetic Field Developed for Contactless Stirring of Low-Conducting Liquid Materials

The use of low electrically conducting liquids is more and more widespread. This is the case for molten glass, salt or slag processing, ionic liquids used in biotechnology, batteries in energy storage and metallurgy. The present paper deals with the design of a new electromagnetic induction device that can heat and stir low electrically-conducting liquids. It consists of a resistance-capacity-inductance circuit coupled with a low-conducting liquid load. The device is supplied by a unique electric power source delivering a single-phase high frequency electric current. The main working principle of the circuit is based on a double oscillating circuit inductor connected to the solid-state transistor generator. This technique, which yields a set of coupled oscillating circuits, consists of coupling a forced phase and an induced phase, neglecting the influence of the electric parameters of the loading part (i.e., the low-conductivity liquid). It is shown that such an inductor is capable to provide a two-phase AC traveling magnetic field at high frequency. To better understand the working principle, the present work improves a previous existing simplified theory by taking into account a complex electrical equivalent diagram due to the different mutual couplings between the two inductors and the two corresponding induced current sets. A more detailed theoretical model is provided, and the key and sensitive elements are elaborated. Based on this theory, equipment is designed to provide a stirring effect on sodium chloride-salted water at 40 S/m. It is shown that such a device fed by several hundred kiloHertz electric currents is able to mimic a linear motor. A set of optimized operating parameters are proposed to guide the experiment. A pure electromagnetic numerical model is presented. Numerical modelling of the load is performed in order to assess the efficiency of the stirrer with a salt water load. Such a device can generate a significant liquid motion with both controlled flow patterns and adjustable amplitude. Based on the magnetohydrodynamic theory, numerical modeling of the salt water flow generated by the stirrer confirms its feasibility.

Revisiting the Role of Convective Deep Water Formation in Northern Baltic Sea Bottom Water Renewal

AbstractDeep water renewal and ventilation of the Baltic Sea is commonly considered to occur solely via saltwater inflows from the North Sea. However, recent analysis of geophysical and sediment proxy data suggests convective deep water formation during wintertime as a second process that has contributed to the ventilation of the northern and central Baltic Sea bottom waters during cold climate periods. Here, we investigate the role of deep water formation in the northern Baltic Sea in a regional ocean circulation model. Selecting the particularly cold winter 1986/1987 as a reference period, we perform sensitivity experiments in which the atmospheric temperature forcing is changed and/or localized brine rejection on subgrid scales is accounted for through a parameterization. We study the sinking and circulation of water masses via passive tracers introduced into the model. Generally, our model results support the established view that convective deep water formation does not play a major role in Baltic Sea deep water renewal. While a reduction of air temperatures does not qualitatively change the sinking and circulation of water masses in our experiments, brine rejection could potentially lead to localized deep water formation. However, the impact is too weak to possibly change the large‐scale deep water exchange between the Baltic proper and the northern Baltic sub‐basins. Although being in line with established knowledge, through consideration of the model limitations, our results provide insights on how and under which circumstances convective deep water formation could potentially have occurred during cold climate periods.

Process intensification using a novel continuous U-shaped crystallizer for freeze desalination

Ice based Freeze Desalination (FD) offers a potential alternative to recover fresh water from seawater. There has been increased interest over the years in the development of continuous crystallizer configurations to address the combined challenge of ice yield and salinity reduction in FD. In this work, experimental studies have been conducted to establish the potential of a novel continuously operated U-shaped crystallizer for ice based Freeze Desalination (FD). Unlike conventional FD crystallizers researched till date, this crystallizer integrates pre-cooling, chilling and freezing of saline water in a single unit along with in-situ ice removal. Preliminary experiments were carried out using synthetic salt water to investigate the effect of salt water flow rate and coolant temperature on product water yield and salinity. Salinity was found to increase with water yield. The overall phase change heat transfer coefficient has also been estimated. Subsequently test runs were carried out using seawater samples under prescribed operating conditions identified from the synthetic salt water runs. Salinity reduction was observed to increase with an increase in number of washing steps and wash water requirement. The results obtained provide a strong case to promote the use of the U-shaped crystallizer for ice based FD.

Effects of Bottom Obstacle Structure on Density-Induced Flow

Density flows frequently occur in nature and some of them have caused serious consequences, such as sedimentation and saline water intrusion. In order to control density flows, the method like placing an obstacle has been proposed. In this paper, the influence of the height and position of obstacle and the salinity difference on the behaviors of lock-exchange density flow was studied experimentally by using high-speed camera and laser particle image velocimetry (PIV) technique. The experiments were conducted in a plexiglass flume whose height, width and depth were 1.8 m, 0.22 m and 0.3 m respectively. Besides, the bottom of the flume is smooth. The flume was separated by one board and the left side of the flume was filled by fresh water while the right side of the flume was filled by salt water. After the board was lifted, the salt water flow into the fresh water and formed a density flow. Obstacles were placed 0.05 m and 0.25 m away from the gate respectively. The velocity and flow field were measured by using the PIV technique. The results indicated that the existence of obstacles blocked the progress of density flow and the propagation distance of density current in the case without obstacle was much longer than the other one which contained obstacle. Additionally, it was observed that when the density flow was crossing over one obstacle, a re-acceleration process was happening at the head of the current, and the maximum velocity caused by this process was larger than the maximum velocity without obstacles. Besides, by comparing the obstacle and non-obstacle situations, the body velocity of density flow was greatly reduced at the front of obstacle. However, the effect of different obstacle positions on the maximum velocity of the head of density flow is not significant.

Black Sea Intrapycnocline Lenses according to the Results of a Numerical Simulation of Basin Circulation

The exact scenario of the propagation of highly saline Marmora Sea waters in the Black Sea basin is not clear. Together with river runoff, they form the prevailing haline stratification of the basin. One regime of their propagation can be the formation of lenses similar to highly salted and warm lenses of the Mediterranean Sea water in the Atlantic Ocean basin. The purpose of this study is the numerical modeling and subsequent analysis of these dynamic structures that form in the Black Sea due to water exchange through the Bosphorus strait. In this case, the main difficulty is the need for high spatial resolution in the strait. The paper provides a brief description of the NEMO ocean-modeling framework used and the features of configuration that make it possible to reproduce the circulation in the basins of the Azov, Black, and Marmara seas with a spatial resolution of 1.16 km. Fields from the ERA5 atmospheric reanalysis are used as the atmospheric forcing. The numerical experiment carried out by us allows reproducing a typical structure of the seasonal variability of the Black Sea rim current and the features of the vertical structure of the basin waters for the period of 2008–2009. The spatial resolution of the results of numerical modeling made it possible to accomplish a high-quality reconstruction of the saltwater dynamics in the basin and at the exit of the Bosphorus strait. Five lenses formed near the strait and captured by the rim current jet were simulated for the period of 2008–2009. They are well-pronounced in the seawater salinity field for the period of 1–2 months. Using one of the lenses as an example, it is shown that its core is located at a depth of about 75 m. The vertical size of the structure is almost 40 m and its horizontal scale is 15 km. The simulation results demonstrate that lens formation events are associated with the gain in the saltwater inflow after storms in the Sea of Marmara basin. Verifying the results of the study can be done based on a specialized field experiment in the Bosphorus region during the periods of the most probable formation of the Black Sea intrapycnocline lenses.

Evaluación técnica para un sistema de calentamiento de agua a través de tubos evacuados en la producción de sal de grano en el Municipio de Petatlán, Gro

The present work focuses on the technical evaluation of a water heating system for the production of salt grain in the coastal region of the municipality of Petatlán, Guerrero, with the purpose of increasing efficiency in the production process of said same product that is obtained by evaporating the water, taking advantage of the abundant available solar resource. For which a solar collector system is designed that through vacuum glass tubes the fluid is circulated at a low speed, increasing its temperature and accelerating the production process. The system is built using low cost materials and with sustainable criteria which is used in exploratory and field research where statistical data on solar radiation, volumetric flow of available salt water, temperature of the environment, among others have been compiled for later be analyzed and together determine the efficiency of the grain salt production process that will benefit the productive sector of the Costa Grande de Guerrero.