Effects of sea bottom topography on hydrothermal circulation: Study on LLucky strike hydrothermal

The waters draining underground from any point of the earth are heated by the hot rock environment warmed by the influence of the magman and they warm up and reach the surface through a route which is different from the way that they are caused by the expansion. These waters emerge on the ground as steam or hot water depending on the temperature of the environment they are in. The environments with this type of cycling are called hydrothermal sources. Generally, hydrothermal sources are located at the points where volcanism is dominant, faults and similar fractures and cracks. The position of magma, which is one of the basic components of hydrothermal systems, is an important factor for the morphology of the separated ridges. The closer the magma chamber is to the top of the sea basin, the faster the spread of the center of the ocean, the farther away from the seabed and the slower the spreading rate in the back will be. Geophysical methods are the most effective way to find hydrothermal areas that are currently active or have lost their activity. It is very difficult to find inactive hydrothermal areas by direct observation. Especially geophysical methods are needed in this section. The important point in the research is to be able to reveal the structural formations. This is the basic parameter for the interstitial search, the sudden changes in the thicknesses of the interlayers, the temperature variation, the fluid movements and the mineralization. The main geophysical methods used to find these formations are seismic, gravitational, magnetic and microscopic. In order to be able to say that an environment is porous, first, the medium must contain small and interconnected gaps in its reservoir when compared to its dimensions, and second, the fluid body must be able to travel from one end of the medium to another. In hollow structures, there are a number of parameters that need to be taken into account in the study of these flows, and porosity is at the top of these. Permeability is another important variable affecting this flow. It is a parameter of the fluid passing through the porous medium, but a property of the porous medium, not of the fluid. In other words, the volume per time is inversely proportional to the length of the flow path, with the flow loss of the fluid over the course of the path. In order for the theorem functions to be applied to liquid fluids, the boundary conditions of the system must be defined by mathematical values. Hence, even if an algebraic expression of flow in a porous environment is established, this theory must be a statistical theory or a theory of laws that only refers to the properties of flow. However, the motion of the fluid in the porous environment can be represented by different functions such as the Oberback-Boussinesq formulation, the flow function formulation, or the non-dimensional formulation. In the models created in the thesis work, both the temperature distributions and the Darcy velocity vectors of the in-situ fluid are evaluated and evaluated by the dimensionless formulation. The Rayleigh number is a dimensionless number that determines how the heat transfer in the fluid will take place. If the value of the Rayleigh number is higher than the critical value, the heat transfer phenomenon takes place by convection, and if it is lower than the critical value, by conduction. Numerical methods and algorithms for analyzing and solving fluid mechanics problems are called computational fluid dynamics (HAD). The finite volume method (SHY) is a widely used approach to computational fluid dynamics, especially since it has advantages over large-scale problems, memory use for high turbulence flows, and solution speed. Ansys Fluent is a program that helps solve the problems of computational fluid dynamics using the finite volume method. Modeling exercises in the shortest sense is to obtain close-up images that are real. The hardest part of modeling is that even the smallest difference that can be computed in the calculation of the parameters can lead to enormous changes to the result, as well as a minimum level of error in the acceptable level. The modeling works in the present thesis study are made in the porous media determined by certain geometric limits, to determine the velocity and direction of the fluid and the underground temperature condition. These studies were conducted in the context of ANSYS FLUENT software, a computational fluid dynamics program that uses the finite volume technique. A set of test models has been developed to check the physical parameters of the fluid in the porous medium prior to a modeling study, which will be generated from the seismic sections and suitable for the in situ shape. The parameters used were determined in accordance with the Lucky Strike hydrothermal field, the study area. Within this context, the topography of the seafloor was modeled to form single and multiple ascents. In addition, the effects of topography were investigated by changing width and height values in single bathymetric elevations. In multiple bathymetric elevations, synthetic modeling studies have been completed by entering different values for elevation, elevation and width. Modeling has been done for various elevations in the sea basin topography, which shows elevation from a single point. The magma chamber is deep in the middle parts of the model. This vent point progresses towards the peak of bathymetric uplift over time and eventually becomes steady-state. The time elapsed since the beginning of the displacement situation during this time and the time required to complete the migration without reaching the steady state depend on the height and width of the prescribed bathymetric height. The results of our modeling studies show that over time, the displacement state of the fluid is inversely proportional to the width of the topographic elevation and is directly dependent on height. As it is known, the topography of the sea basin does not have a regular structure. There are a number of irregularities that occur due to the different fluid movements in the location and the annual opening times of the ocean-centered backs. As a result of this, in the next part of the modeling study, the cases that can occur when the bathymetric rise is multiple are examined. The area where the modeling work is done is the Lucky Strike hydrotermal area, which has 21 hydrothermal vent points and about 150 km2 area in the Azor archipelago, a region of Portugal connected to the Atlantic Ocean. Mapping of the faults and fracture geometry is done only by the reflection seismic method. For this reason, in order to start the modeling works by moving, seismic reflections studies made in the region have been examined. In the result of literature study, stratigraphic interpretation and reflection power sections were used in modeling studies. In this study, the effects of hydrothermal circulation on the seafloor topography were researched and modeled and applied to the field of Lucky Strike Hydrotermal as a study area. First of all, the difference between the widths and lengths of the single bathymetric elevation was investigated and then the case of the magma chamber to the right and left of the topographic elevation was investigated. Following these studies, the effects of batimetrin on hydrothermal circulation in the case of multiple bathymetric ascension have been investigated. At the same time, four models with different heights and widths were created and modeled. In the last part of the work, a modeling study was carried out in the field of Lucky Strike Hydrothermal which is irregular but has a symmetrical structure from the middle of the basin.