{"id":91084,"date":"2009-08-01T00:00:00","date_gmt":"2009-08-01T00:00:00","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/simulation-and-calibration-of-density-dependent-flow-problems-in-porous-media\/"},"modified":"2009-08-01T00:00:00","modified_gmt":"2009-08-01T00:00:00","slug":"simulation-and-calibration-of-density-dependent-flow-problems-in-porous-media","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/politecnica-de-catalunya\/simulation-and-calibration-of-density-dependent-flow-problems-in-porous-media\/","title":{"rendered":"Simulation and calibration of density-dependent flow problems in porous media"},"content":{"rendered":"<h2>Tesis doctoral de <strong> Juan  Jos\u00e9 Hidalgo Gonz\u00e1lez <\/strong><\/h2>\n<p>Groundwater models have become an irreplaceable tool in hydrology. Density-dependent flow and transport simulation is specially challenging for  numerical models because of its non linear coupled nature. Density dependence affects many groundwater problems, e.G., Saltwater intrusion in coastal  aquifers, heat storage or contaminant remediation. This thesis deals with four open issues in density-dependent flow and transport in groundwater  problems. first, boundary and internal salt sources are usually neglected in the fluid mass balance. Here, they are formally introduced. Their effect is quantified on  two examples. These show that neglecting salt sources causes head to decrease, which contradicts basic physical principles. As a result, an inversion  in the flow direction is observed. Discrepancies in concentrations are mild, except when the prescribed salt mass fraction is close to one. However, it  can be concluded that pure salt sources, when present, need to be included in the flow equation whenever detailed descriptions of flow or accurate  mass balances are sought. second, injection of dioxc in saline aquifers is often studied under a number of simplifications. Dispersion is neglected and the dioxc-brine interface  is treated as a prescribed concentration boundary by analogy with a thermal convection problem. In this thesis, the effect of accounting for the dioxc  mass flux across the prescribed concentration boundary and hydrodynamic dispersion on the onset of convection during dioxc injection is studied. It  was found that accounting for the dioxc mass flux does not change qualitatively the time for the onset of the convective regime but accounting for  dispersion causes a significant reduction on the time it takes for convection to become the dominant transport mechanism. This implies that dioxc  dissolution can be accelerated by activating dispersion as a transport mechanism, which can be achieved by adopting a fluctuating injection regime. spatial variability of hydraulic conductivity is known to cause dispersion. However, the use of a dispersion term in addition to thermal conductivity is not  widely accepted. The third objective addressed in this thesis is to investigate the dispersion of a heat plume generated by a groundwater heat  exchanger under steady state conditions. To that end, a three-dimensional model of  a groundwater heat exchanger is studied under a stochastic  approach. Density effects are not included in the model because they are considered of smaller order compared to those of heterogeneity in the  hydraulic conductivity. Results show that heterogeneity in aquifer conductivity increases transverse dispersion near the heat source. Then, it decreases  with the distance from the heat source. Despite the influence in the plume dispersion, no relevant effects in the performance of the thermal device were  found. finally, a new algorithm for the calibration of density-dependent flow and transport models is presented. The algorithm takes advantage of the newton  method and the analytical computation of the sensitivity matrix. A synthetic saltwater intrusion model is calibrated to test the efficiency of the algorithm.  its performance is compared with the usual combination of picard method and parameter perturbation for the computation of sensitivities.  computational performance tests showed a reduction in the cpu time needed for calibration. Moreover, it was found that the cost per additional  calibrated parameter was significantly lower using the new algorithm. This allows modellers to increase the number of parameters to calibrate, i.E., The  complexity of the model, without substantially increasing the cost of the calibration process.<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Simulation and calibration of density-dependent flow problems in porous media<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Simulation and calibration of density-dependent flow problems in porous media <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Juan  Jos\u00e9 Hidalgo Gonz\u00e1lez <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Polit\u00e9cnica de catalunya<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 08\/01\/2009<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>Jes\u00fas Carrera Ram\u00edrez<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: philippe Ackerer <\/li>\n<li>rub\u00e9n Juan es (vocal)<\/li>\n<li>xavier S\u00e1nchez vila (vocal)<\/li>\n<li>orlando Silva rojas (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Juan Jos\u00e9 Hidalgo Gonz\u00e1lez Groundwater models have become an irreplaceable tool in hydrology. Density-dependent flow and transport [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[15596],"tags":[15765,188805,126389,30536,188806,30533],"class_list":["post-91084","post","type-post","status-publish","format-standard","hentry","category-politecnica-de-catalunya","tag-jesus-carrera-ramirez","tag-juan-jose-hidalgo-gonzalez","tag-orlando-silva-rojas","tag-philippe-ackerer","tag-ruben-juan-es","tag-xavier-sanchez-vila"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/91084","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/comments?post=91084"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/91084\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=91084"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=91084"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=91084"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}