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  Subjects -> GEOGRAPHY (Total: 493 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
40 [degrees] South     Full-text available via subscription   (Followers: 1)
AAG Review of Books     Hybrid Journal   (Followers: 2)
AbeÁfrica : Revista da Associação Brasileira de Estudos Africanos     Open Access  
ACME : An International Journal for Critical Geographies     Open Access   (Followers: 1)
Acta Universitatis Lodziensis : Folia Geographica Socio-Oeconomica     Open Access   (Followers: 1)
Adam Academy : Journal of Social Sciences / Adam Akademi : Sosyal Bilimler Dergisi     Open Access   (Followers: 3)
Advances in Cartography and GIScience of the ICA     Open Access   (Followers: 3)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Statistical Climatology, Meteorology and Oceanography     Open Access   (Followers: 11)
Africa Insight     Full-text available via subscription   (Followers: 16)
Africa Spectrum     Open Access   (Followers: 16)
African Geographical Review     Hybrid Journal   (Followers: 2)
Afrika Focus     Open Access   (Followers: 1)
AGORA Magazine     Open Access   (Followers: 1)
Agronomía & Ambiente     Open Access   (Followers: 1)
AGU Advances     Open Access   (Followers: 1)
All Earth     Open Access   (Followers: 3)
American Journal of Geographic Information System     Open Access   (Followers: 14)
American Journal of Human Ecology     Open Access   (Followers: 11)
American Journal of Rural Development     Open Access   (Followers: 5)
Amerika     Open Access   (Followers: 1)
Anales de Geografía de la Universidad Complutense     Open Access  
Anatoli     Open Access  
Annales Universitatis Paedagogicae Cracoviensis / Studia de Cultura     Open Access  
Annals of GIS     Open Access   (Followers: 32)
Annals of the American Association of Geographers     Hybrid Journal   (Followers: 43)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 13)
Antipode     Hybrid Journal   (Followers: 65)
Anuario     Open Access  
Applied Geography     Hybrid Journal   (Followers: 39)
Applied Geomatics     Hybrid Journal   (Followers: 4)
Ar@cne     Open Access  
Arctic     Open Access   (Followers: 2)
Arctic Science     Open Access   (Followers: 7)
Area Development and Policy     Hybrid Journal   (Followers: 1)
Asia Policy     Full-text available via subscription   (Followers: 6)
Asian Geographer     Hybrid Journal   (Followers: 5)
Asian Journal of Geographical Research     Open Access   (Followers: 2)
Ateneo Korean Studies Conference Proceedings     Open Access  
Atmospheric Measurement Techniques (AMT)     Open Access   (Followers: 19)
Atmospheric Measurement Techniques Discussions (AMTD)     Open Access   (Followers: 9)
Aurora Journal     Full-text available via subscription  
Australian Antarctic Magazine     Free   (Followers: 5)
Australian Geographer     Hybrid Journal   (Followers: 6)
Bandung : Journal of the Global South     Open Access   (Followers: 1)
Barn : Forskning om barn og barndom i Norden     Open Access  
Baru : Revista Brasileira de Assuntos Regionais e Urbanos     Open Access  
Belgeo     Open Access   (Followers: 2)
Biblio3W : Revista Bibliográfica de Geografía y Ciencias Sociales     Open Access  
Biogeographia : The Journal of Integrative Biogeography     Open Access   (Followers: 2)
BioRisk     Open Access   (Followers: 2)
Boletim Campineiro de Geografia     Open Access  
Boletim de Ciências Geodésicas     Open Access  
Boletim Gaúcho de Geografia     Open Access  
Boletim Goiano de Geografia     Open Access  
Boletín de Estudios Geográficos     Open Access  
Boletín de la Asociación de Geógrafos Españoles     Open Access  
Brill Research Perspectives in Map History     Full-text available via subscription   (Followers: 1)
Buildings & Landscapes: Journal of the Vernacular Architecture Forum     Full-text available via subscription   (Followers: 13)
Bulletin de la Société Géographique de Liège     Open Access  
Bulletin de l’association de géographes français     Open Access   (Followers: 1)
Bulletin of Geography. Physical Geography Series     Open Access   (Followers: 4)
Bulletin of Geography. Socio-economic Series     Open Access   (Followers: 3)
Bulletin of Geosciences     Open Access   (Followers: 12)
Bulletin of the Ecological Society of America     Open Access   (Followers: 4)
Bulletin of the Serbian Geographical Society     Open Access  
Caderno de Geografia     Open Access  
Cahiers Balkaniques     Open Access   (Followers: 2)
Cahiers Charlevoix : Études franco-ontariennes     Full-text available via subscription  
Cahiers franco-canadiens de l'Ouest     Full-text available via subscription   (Followers: 2)
California Italian Studies Journal     Full-text available via subscription   (Followers: 7)
Canadian Journal of Latin American and Caribbean Studies     Hybrid Journal   (Followers: 10)
Canadian Journal of Soil Science     Full-text available via subscription   (Followers: 11)
Cardinalis     Open Access  
Carnets de géographes     Open Access  
Cartographic Journal     Hybrid Journal   (Followers: 9)
Cartographic Perspectives     Open Access   (Followers: 2)
Cartographica : The International Journal for Geographic Information and Geovisualization     Full-text available via subscription   (Followers: 17)
Cartography and Geographic Information Science     Hybrid Journal   (Followers: 31)
Check List : The Journal of Biodiversity Data     Open Access   (Followers: 2)
China : An International Journal     Full-text available via subscription   (Followers: 20)
Climate and Development     Hybrid Journal   (Followers: 34)
Climate Change Economics     Hybrid Journal   (Followers: 50)
Comparative Cultural Studies : European and Latin American Perspectives     Open Access   (Followers: 5)
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Urban Science     Open Access   (Followers: 1)
Confins     Open Access  
Conjuntura Austral : Journal of the Global South     Open Access   (Followers: 2)
Coolabah     Open Access  
Creativity Studies     Open Access   (Followers: 5)
Critical Romani Studies     Open Access  
Crossings : Journal of Migration & Culture     Hybrid Journal   (Followers: 16)
Cuadernos de Desarrollo Rural     Open Access  
Cuadernos de Geografía : Revista Colombiana de Geografía     Open Access  
Cuadernos de Geografía de la Universitat de València     Open Access  
Cuadernos de Investigación Geográfica / Geographical Research Letters     Open Access  
Cuadernos Inter.c.a.mbio sobre Centroamérica y el Caribe     Open Access   (Followers: 1)
Current Research in Geoscience     Open Access   (Followers: 5)
Dela     Open Access  
Dialogues in Human Geography     Hybrid Journal   (Followers: 20)
Didáctica Geográfica     Open Access  
DIE ERDE : Journal of the Geographical Society of Berlin     Open Access   (Followers: 1)
Documenti Geografici     Open Access  
Documents d'Anàlisi Geogràfica     Open Access  
Doğu Coğrafya Dergisi : Eastern Geographical Review     Open Access  
DRd - Desenvolvimento Regional em debate     Open Access  
Earth System Governance     Open Access   (Followers: 1)
Earth Systems and Environment     Hybrid Journal   (Followers: 3)
East/West : Journal of Ukrainian Studies     Open Access  
Eastern European Countryside     Open Access   (Followers: 2)
Economic and Regional Studies / Studia Ekonomiczne i Regionalne     Open Access  
Economic Geography     Hybrid Journal   (Followers: 42)
Économie rurale     Open Access   (Followers: 3)
Ecosystems and People     Open Access   (Followers: 4)
Entorno Geográfico     Open Access  
Environment & Ecosystem Science     Open Access   (Followers: 3)
Environmental and Sustainability Indicators     Open Access   (Followers: 7)
Environmental Science : Atmospheres     Open Access   (Followers: 1)
Environmental Science and Sustainable Development : International Journal Of Environmental Science & Sustainable Development     Open Access   (Followers: 13)
Environmental Smoke     Open Access  
Ería : Revista Cuatrimestral de Geografía     Open Access  
Espacio y Desarrollo     Open Access  
Espacios : Revista de |Geografía     Open Access  
Espaço & Economia : Revista Brasileira de Geografia Econômica     Open Access  
Espaço Aberto     Open Access  
Espaço e Cultura     Open Access  
Espaço e Tempo Midiáticos     Open Access  
Estudios Geográficos     Open Access   (Followers: 1)
Estudios Socioterritoriales : Revista de Geografía     Open Access  
Ethnobiology Letters     Open Access  
Ethnoscientia : Brazilian Journal of Ethnobiology and Ethnoecology     Open Access  
eTropic : electronic journal of studies in the tropics     Open Access  
Études internationales     Full-text available via subscription   (Followers: 1)
Études rurales     Open Access   (Followers: 2)
Études/Inuit/Studies     Full-text available via subscription  
European Bulletin of Himalayan Research     Open Access   (Followers: 6)
European Countryside     Open Access   (Followers: 1)
European Spatial Research and Policy     Open Access   (Followers: 9)
Evolutionary Human Sciences     Open Access   (Followers: 5)
Fennia : International Journal of Geography     Open Access   (Followers: 1)
Finisterra : Revista Portuguesa de Geografia     Open Access  
Fire Ecology     Open Access   (Followers: 3)
Florida Geographer     Open Access   (Followers: 1)
Focus on Geography     Partially Free   (Followers: 5)
Forum Geografi     Open Access  
Frontera Norte     Open Access  
GEM - International Journal on Geomathematics     Hybrid Journal   (Followers: 1)
Genre & histoire     Open Access   (Followers: 4)
Geo : Geography and Environment     Open Access   (Followers: 8)
Geo UERJ     Open Access  
Geo-Image     Open Access   (Followers: 1)
Geo-spatial Information Science     Open Access   (Followers: 7)
GeoArabia     Hybrid Journal  
Géocarrefour     Open Access  
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 34)
Geochronometria     Open Access   (Followers: 1)
Geoderma Regional : The International Journal for Regional Soil Research     Full-text available via subscription   (Followers: 4)
Geodesy and Cartography     Open Access   (Followers: 2)
Geoforum Perspektiv     Open Access   (Followers: 1)
Geofronter     Open Access  
Geografares     Open Access  
Geografisk Tidsskrift-Danish Journal of Geography     Hybrid Journal   (Followers: 3)
Geografiska Annaler, Series A : Physical Geography     Hybrid Journal   (Followers: 4)
Geographia     Open Access   (Followers: 1)
Geographica Helvetica     Open Access   (Followers: 13)
Geographical Analysis     Hybrid Journal   (Followers: 11)
Geographical Education     Full-text available via subscription   (Followers: 2)
Geographical Journal of Nepal     Open Access  
Geographical Research     Hybrid Journal   (Followers: 11)
Geographical Review     Hybrid Journal   (Followers: 13)
Geographicalia     Open Access  
Géographie et cultures     Open Access   (Followers: 3)
Geography and Natural Resources     Hybrid Journal   (Followers: 10)
Geography and Sustainability     Open Access   (Followers: 2)
Geography Compass     Hybrid Journal   (Followers: 18)
GeoHumanities     Hybrid Journal   (Followers: 2)
GeoInformatica     Hybrid Journal   (Followers: 7)
Geoinformatics & Geostatistics     Hybrid Journal   (Followers: 14)
Geoinformatics FCE CTU     Open Access   (Followers: 8)
Geoingá : Revista do Programa de Pós-Graduação em Geografia     Open Access  
GeoJournal     Hybrid Journal   (Followers: 11)
GEOMATICA     Hybrid Journal   (Followers: 1)
Geomatics, Natural Hazards and Risk     Open Access   (Followers: 14)
GEOmedia     Open Access   (Followers: 1)
Geopauta : Revista de Geografia da Universidade Estadual do Sudoeste da Bahia     Open Access  
Geophysical Research Letters     Full-text available via subscription   (Followers: 183)
Geoplanning : Journal of Geomatics and Planning     Open Access   (Followers: 5)
GeoScape     Open Access  
Geosciences Journal     Hybrid Journal   (Followers: 11)
Geosphere     Open Access   (Followers: 2)
GEOUSP : Espaço e Tempo     Open Access  
Ghana Journal of Geography     Open Access   (Followers: 11)
Ghana Studies     Full-text available via subscription   (Followers: 15)
GIScience & Remote Sensing     Open Access   (Followers: 54)
Global Challenges     Open Access   (Followers: 1)
Global Sustainability     Open Access   (Followers: 5)
Globe, The     Full-text available via subscription   (Followers: 4)
GPS Solutions     Hybrid Journal   (Followers: 28)
Grafo Working Papers     Open Access  
HiN : Alexander von Humboldt im Netz. Internationale Zeitschrift für Humboldt-Studien     Open Access  

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Similar Journals
Journal Cover
GEM - International Journal on Geomathematics
Journal Prestige (SJR): 0.321
Citation Impact (citeScore): 1
Number of Followers: 1  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1869-2672 - ISSN (Online) 1869-2680
Published by Springer-Verlag Homepage  [2469 journals]
  • A comparative study of integral and coupled approaches for modeling
           hydraulic exchange processes across a rippled streambed

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      Abstract: Abstract Although both are crucial parts of the hydrological cycle, groundwater and surface water had traditionally been addressed separately. In recent decades, considering them as a single hydrological continuum in light of their continuous interaction has become well established in the scientific community through the development of numerous measurement and experimental techniques. Nevertheless, numerical models, as necessary tools to study a wide range of scenarios and future event predictions, are still based on outdated concepts that consider groundwater and surface water separately. This study compares these “coupled models”, which result from the successive execution of a surface water model and a groundwater model, to a recently developed “integral model”. The integral model uses a single set of equations to model both groundwater and surface water simultaneously, and can account for the continuous interaction at their interface. For comparison, we investigated small-scale flow across a rippled porous streambed. Although we applied identical model domain details and flow conditions, which resulted in very similar water tables and pressure distributions, comparing the integral and coupled models yielded very dissimilar velocity values across the groundwater–surface water interface. These differences highlight the impact of continuous exchange across the interface in the integral model, which imitates such flow processes more realistically than the coupled model. A few decimeters away from the interface, modeled velocity fields are very similar. Since the integral model and the surface water component of the coupled model are both CFD-based (computational fluid dynamics), they require very similar computational resources, namely access to cluster computers. Unfortunately, replacing the surface water component of the coupled model with the widely used shallow water equations model, which indeed would reduce the computational resources required, produces inaccuracy.
      PubDate: 2022-09-13
       
  • A self-similar solution for transient Darcy–Forchheimer flow in an
           aquifer

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      Abstract: Abstract In this study we examine the classical problem of fluid flow in an aquifer, obeying the transient Darcy–Forchheimer law. This problem is solved by using the symmetry properties of the governing equations (e.g. the mass balance equation and the transient Darcy–Forchheimer momentum equation) which enable us to transform the time and the space coordinates into one independent coordinate. According to our study the flow in the aquifer may be divided into two main components. One component is the steady part of the flow discharge and the other one is the transient part of the flow discharge. The obtained solution shows that the reduction in the above-mentioned transient part leads to the creation of three zones: (1) the “near zone” located near the inlet face to the aquifer and is characterized by a positive flow; (2) the “far zone” in the aquifer lying at an infinite distance from the inlet face where the flow is also positive and (3) the “intermediate backflow zone”, which is lying among the above-mentioned zones and is characterized by reverse flow. The results obtained in this study may be useful for understanding the transient flow process in the aquifer, stemming from the Darcy–Forchheimer flow, and for the prediction of the discharge and head distribution in the aquifer.
      PubDate: 2022-08-19
       
  • Generation of SH-wave in a medium of welded two-quarter spaces with a
           uniform layer on one quarter space

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      Abstract: Abstract This paper examines the generation of elastic SH-waves in a medium of two-quarter spaces in welded contact with a layer of uniform thickness overlying one of the quarter spaces. Impulsive surface tractions on the surface generate the waves. Transform methods are employed to obtain the functional integral equation in the general case. Approximations are made when a layer overlies a halfspace to obtain the solution. The displacement at the surface of the layer is obtained as a series of definite integrals representing the different pulses reflected at the interface between the layer and the halfspace.
      PubDate: 2022-08-02
       
  • A forecasting model for the porosity variation during the carbonation
           process

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      Abstract: Abstract In this paper we introduce a mathematical model of concrete carbonation Portland cement specimens. The main novelty of this work is to describe the intermediate chemical reactions, occurring in the carbonation process of concrete, involving the interplay of carbon dioxide with the water present into the pores. Indeed, the model here proposed, besides describing transport and diffusion processes inside the porous medium, takes into account both fast and slow phenomena as intermediate reactions of the carbonation process. As a model validation, by using the mathematical based simulation algorithm we are able to describe the effects of the interaction between concrete and CO \(_2\) on the porosity of material as shown by the numerical results in substantial accordance with experimental results of accelerated carbonation taken from literature. We also considered a further reaction: the dissolution of calcium carbonate under an acid environment. As a result, a trend inversion in the evolution of porosity can be observed for long exposure times. Such an increase in porosity results in the accessibility of solutions and pollutants within the concrete leading to an higher permeability and diffusivity thus significantly affecting its durability.
      PubDate: 2022-07-25
       
  • The geophysical KdV equation: its solitons, complexiton, and conservation
           laws

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      Abstract: Abstract The main goal of the current paper is to analyze the impact of the Coriolis parameter on nonlinear waves by studying the geophysical KdV equation. More precisely, specific transformations are first adopted to derive one-dimensional and operator forms of the governing model. Solitons and complexiton of the geophysical KdV equation are then retrieved with the help of several well-established approaches such as the Kudryashov and Hirota methods. In the end, the new conservation theorem given by Ibragimov is formally employed to extract conservation laws of the governing model. It is shown that by increasing the Coriolis parameter, based on the selected parameter regimes, less time is needed for tending the free surface elevation to zero.
      PubDate: 2022-07-24
       
  • Propagation of hydropeaking waves in heterogeneous aquifers: effects on
           flow topology and uncertainty quantification

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      Abstract: Topological flow properties are proxies for mixing processes in aquifers and allow us to better understand the mechanisms controlling transport of solutes in the subsurface. However, topological descriptors, such as the Okubo–Weiss metric, are affected by the uncertainty in the solution of the flow problem. While the uncertainty related to the heterogeneous properties of the aquifer has been widely investigated in the past, less attention has been given to the one related to highly transient boundary conditions. We study the effect of different transient boundary conditions associated with hydropeaking events (i.e., artificial river stage fluctuations due to hydropower production) on groundwater flow and the Okubo–Weiss metric. We define deterministic and stochastic modeling scenarios applying four typical settings to describe river stage fluctuations during hydropeaking events: a triangular wave, a sine wave, a complex wave that results of the superposition of two sine waves, and a trapezoidal wave. We use polynomial chaos expansions to quantify the spatiotemporal uncertainty that propagates into the hydraulic head in the aquifer and the Okubo–Weiss. The wave-shaped highly transient boundary conditions influence not only the magnitude of the deformation and rotational forces of the flow field but also the temporal dynamics of dominance between local strain and rotation properties. Larger uncertainties are found in the scenario where the trapezoidal wave was imposed due to sharp fluctuation in the stage. The statistical moments that describe the propagation of the uncertainty highly vary depending on the applied boundary condition. Highlights Deterministic and stochastic scenarios to describe the groundwater flow field under river stage fluctuations during hydropeaking. Propagation of uncertainty of highly transient boundary conditions in the Okubo–Weiss metric. Highly transient boundary conditions can significantly affect mixing potential.
      PubDate: 2022-07-22
       
  • Permeability extraction from multiple well logs using particle swarm
           optimization based factor analysis

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      Abstract: Abstract In this paper, we present an innovative factor analysis algorithm for hydrocarbon exploration to estimate the intrinsic permeability of reservoir rocks from well logs. Unlike conventional evaluation methods that employ a single or a limited number of data types, we process simultaneously all available data to derive the first statistical factor and relate it to permeability by regression analysis. For solving the problem of factor analysis, we introduce an improved particle swarm optimization method, which searches for the global minimum of the distance between the observed and calculated data and gives a quick estimation for the factor scores. The learning factors of the intelligent computational technique such as the cognitive and social constants are specified as hyperparameters and calculated by using simulated annealing algorithm as heuristic hyperparameter estimator. Instead of the arbitrary fixation of these hyperparameters, we refine them in an iterative process to give reliable estimation both for the statistical factors and formation permeability. The estimated learning parameters are consistent with literature recommendations. We demonstrate the feasibility of the proposed well-log analysis method by a Hungarian oilfield study involving open-hole wireline logs and core data. We determine the spatial distribution of permeability both along a borehole and between more wells using the factor analysis approach, which serves as efficient and reliable multivariate statistical tool for advanced formation evaluation and reservoir modeling.
      PubDate: 2022-06-25
      DOI: 10.1007/s13137-022-00200-x
       
  • Recovery of wave speeds and density of mass across a heterogeneous smooth
           interface from acoustic and elastic wave reflection operators

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      Abstract: Abstract We revisit the problem of recovering wave speeds and density across a curved interface from reflected wave amplitudes. Such amplitudes have been exploited for decades in (exploration) seismology in this context. However, the analysis in seismology has been based on linearization and mostly flat interfaces. Here, we present an analysis without linearization and allow curved interfaces, establish uniqueness and provide a reconstruction, while making the notion of amplitude precise through a procedure rooted in microlocal analysis.
      PubDate: 2022-05-13
      DOI: 10.1007/s13137-022-00199-1
       
  • On the existence of Parker’s ideal bodies

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      Abstract: Abstract After a short introduction on the historical context, the paper deals with the existence of the solution of Parker’s ideal body problem, namely the body of minimum constant density generating a given external potential. A crucial element of the proof is the use of a recently introduced topological space of closed sets, closed and compact with the distance defined as the Lebesgue measure of the symmetric difference of a couple of sets. Such a space is indeed smaller than that of all closed sets of a given B, but larger than that of star-shaped Lipschitz domains, where previous studies of the inverse gravimetric problem (with constant density) have been conducted. However, with the present knowledge, it is only in this class that a uniqueness theorem holds.
      PubDate: 2022-05-11
      DOI: 10.1007/s13137-022-00198-2
       
  • Optimal experiment design for a bottom friction parameter estimation
           problem

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      Abstract: Abstract Calibration with respect to a bottom friction parameter is standard practice within numerical coastal ocean modelling. However, when this parameter is assumed to vary spatially, any calibration approach must address the issue of overfitting. In this work, we derive calibration problems in which the control parameters can be directly constrained by available observations, without overfitting. This is achieved by carefully selecting the ‘experiment design’, which in general encompasses both the observation strategy, and the choice of control parameters (i.e. the spatial variation of the friction field). In this work we focus on the latter, utilising existing observations available within our case study regions. We adapt a technique from the optimal experiment design (OED) literature, utilising model sensitivities computed via an adjoint-capable numerical shallow water model, Thetis. The OED method uses the model sensitivity to estimate the covariance of the estimated parameters corresponding to a given experiment design, without solving the corresponding parameter estimation problem. This facilitates the exploration of a large number of such experiment designs, to find the design producing the tightest parameter constraints. We take the Bristol Channel as a primary case study, using tide gauge data to estimate friction parameters corresponding to a piecewise-constant field. We first demonstrate that the OED framework produces reliable estimates of the parameter covariance, by comparison with results from a Bayesian inference algorithm. We subsequently demonstrate that solving an ‘optimal’ calibration problem leads to good model performance against both calibration and validation data, thus avoiding overfitting.
      PubDate: 2022-04-30
      DOI: 10.1007/s13137-022-00196-4
       
  • Semi-analytical solutions for the problem of the electric potential set in
           a borehole with a highly conductive casing

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      Abstract: Abstract Highly conductive thin casings pose a great challenge in the numerical simulation of well-logging instruments. Witty asymptotic models may replace the presence of casings by impedance transmission conditions in those numerical simulations. The accuracy of such numerical schemes can be tested against benchmark solutions computed semi-analytically in simple geometrical configurations. This paper provides a general approach to construct those benchmark solutions for three different models: one reference model that indeed considers the presence of the casing; one asymptotic model that avoids computations in the casing domain; and one asymptotic model that reduces the presence of the casing to an interface. Our technique uses a Fourier representation of the solutions, where special care has been taken in the analytical integration of singularities to avoid numerical instabilities.
      PubDate: 2022-04-29
      DOI: 10.1007/s13137-022-00197-3
       
  • Rayleigh wave propagation in a nonlocal isotropic magneto-thermoelastic
           solid with multi-dual-phase lag heat transfer

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      Abstract: Abstract The present paper deals with Rayleigh wave propagation in a homogeneous isotropic nonlocal magneto-thermoelastic solid with hall current and rotation. The considered thermoelastic solid is subjected to multi-dual-phase lag heat transfer. The Secular equations of Rayleigh waves are derived mathematically at the stress-free and thermally insulated boundaries. The values of stress components, temperature change, phase velocity, attenuation coefficient, penetration depth and specific loss have been computed numerically and depicted graphically. The effects of hall current and nonlocal parameter have been depicted on the various wave quantities. Some particular cases have also been deduced from the present investigation.
      PubDate: 2022-04-01
      DOI: 10.1007/s13137-022-00195-5
       
  • Variational principle for some nonlinear problems

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      Abstract: Abstract A variational principle is established by the semi-inverse method and used to solve approximately a nonlinear problem by the Ritz method. In this process,it may be difficult to solve a large system of algebraic equations,the Groebner bases theory (Buchberger’s algorithm) is applied to solve this problem. The results show that the variational approach is much simpler and more efficient.
      PubDate: 2022-02-04
      DOI: 10.1007/s13137-022-00194-6
       
  • A study of moisture content in unsaturated porous medium by using homotopy
           perturbation method (HPM) and variational iteration method (VIM)

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      Abstract: Abstract Vertical infiltration of water plays an important role in the recharged of contaminated water and enhanced moisture content in the unsaturated porous media. The mathematical model used for such type of phenomenon is Burger's equation. Unsaturated porous media are analyzed by solving Burger's equation using the variational iterative modeling and homotopy perturbation method. When considering all moisture contents, it appears that the cumulative coefficient is unchanged. It is also shown that the soil's moisture content decreases with depth (y) and time (t). The results indicate that this method is very efficient and can be useful to solve large-scale problems that arise in civil engineering, geology, material science, and fossil fuel problems.
      PubDate: 2022-01-06
      DOI: 10.1007/s13137-021-00193-z
       
  • Multi-scale hydro-morphodynamic modelling using mesh movement methods

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      Abstract: Abstract Hydro-morphodynamic modelling is an important tool that can be used in the protection of coastal zones. The models can be required to resolve spatial scales ranging from sub-metre to hundreds of kilometres and are computationally expensive. In this work, we apply mesh movement methods to a depth-averaged hydro-morphodynamic model for the first time, in order to tackle both these issues. Mesh movement methods are particularly well-suited to coastal problems as they allow the mesh to move in response to evolving flow and morphology structures. This new capability is demonstrated using test cases that exhibit complex evolving bathymetries and have moving wet-dry interfaces. In order to be able to simulate sediment transport in wet-dry domains, a new conservative discretisation approach has been developed as part of this work, as well as a sediment slide mechanism. For all test cases, we demonstrate how mesh movement methods can be used to reduce discretisation error and computational cost. We also show that the optimum parameter choices in the mesh movement monitor functions are fairly predictable based upon the physical characteristics of the test case, facilitating the use of mesh movement methods on further problems.
      PubDate: 2021-12-09
      DOI: 10.1007/s13137-021-00191-1
       
  • A gradient based resolution strategy for a PDE-constrained optimization
           approach for 3D-1D coupled problems

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      Abstract: Abstract Coupled 3D-1D problems arise in many practical applications, in an attempt to reduce the computational burden in simulations where cylindrical inclusions with a small section are embedded in a much larger domain. Nonetheless the resolution of such problems can be non trivial, both from a mathematical and a geometrical standpoint. Indeed 3D-1D coupling requires to operate in non standard function spaces, and, also, simulation geometries can be complex for the presence of multiple intersecting domains. Recently, a PDE-constrained optimization based formulation has been proposed for such problems, proving a well posed mathematical formulation and allowing for the use of non conforming meshes for the discrete problem. Here an unconstrained optimization formulation of the problem is derived and an efficient gradient based solver is proposed for such formulation, along with a suitable preconditioner to speed up the iterative solver. Some numerical tests on quite complex configurations are discussed to show the viability of the method .
      PubDate: 2021-12-08
      DOI: 10.1007/s13137-021-00192-0
       
  • Solitary waves of the fractal Whitham–Broer–Kaup equation in
           shallow water

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      Abstract: Abstract In the current work, we propose the fractal Whitham–Broer–Kaup equation which can well describe the propagation of shallow water travelling along unsmooth boundary (such as the fractal seabed). By the Semi-inverse method, we establish its fractal variational principle, which is proved to have a strong minimum condition by He–Weierstrass theorem. Then the fractal variational method is used to seek its solitary wave solution. The impact of the fractal order on the behaviors of the solitary wave is presented through the 3-D plots and 2-D curves. The finding in this paper is important for the coast protection and expected to bring a light to the study of the fractal theoretical basis in the geosciences.
      PubDate: 2021-10-22
      DOI: 10.1007/s13137-021-00189-9
       
  • Effects of temperature- and pressure-dependent viscosity and internal
           heating on mantle convection

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      Abstract: Abstract A mathematical model is considered for Rayleigh–Bénard convection of mantle where the viscosity depends strongly on both temperature and pressure defined in an Arrhenius form. The model is solved numerically for extremely large viscosity variations across a unit aspect ratio cell using a modified cut-off viscosity law, and steady solutions are obtained. The aim is to investigate the convection pattern with internal heating at a very high viscosity variation in the presence of high Rayleigh number. The study also investigates the relation between temperature dependent parameter and pressure dependent parameter in a basally heated convection cell. The numerical simulation is performed using the finite element method based PDE solver and the results are presented through figures, tables and graphs.
      PubDate: 2021-10-22
      DOI: 10.1007/s13137-021-00190-2
       
  • The use of B-splines to represent the topography of river networks

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      Abstract: Abstract This work presents a new extension to B-Splines that enables them to model functions on directed tree graphs such as non-braided river networks. The main challenge of the application of B-splines to graphs is their definition in the neighbourhood of nodes with more than two incident edges. Achieving that the B-splines are continuous at these points is non-trivial. For both, simplification reasons and in view of our application, we limit the graphs to directed tree graphs. To fulfil the requirement of continuity, the knots defining the B-Splines need to be located symmetrically along the edges with the same direction. With such defined B-Splines, we approximate the topography of the Mekong River system from scattered height data along the river. To this end, we first test and validate successfully the method with synthetic water level data, with and without added annual signal. The quality of the resulting heights is assessed besides others by means of root mean square errors (RMSE) and mean absolute differences (MAD). The RMSE values are 0.26 m and 1.05 m without and with added annual variation respectively and the MAD values are even lower with 0.11 m and 0.60 m. For the second test, we use real water level observations measured by satellite altimetry. Again, we successfully estimate the river topography, but also discuss the short comings and problems with unevenly distributed data. The unevenly distributed data leads to some very large outliers close to the upstream ends of the rivers tributaries and in regions with rapidly changing topography such as the Mekong Falls. Without the outlier removal the standard deviation of the resulting heights can be as large as 50 m with a mean value of 15.73 m. After the outlier removal the mean standard deviation drops to 8.34 m.
      PubDate: 2021-09-22
      DOI: 10.1007/s13137-021-00188-w
       
  • Polynomial surrogates for Bayesian traveltime tomography

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      Abstract: Abstract This paper tackles the issue of the computational load encountered in seismic imaging by Bayesian traveltime inversion. In Bayesian inference, the exploration of the posterior distribution of the velocity model parameters requires extensive sampling. The computational cost of this sampling step can be prohibitive when the first arrival traveltime prediction involves the resolution of an expensive number of forward models based on the eikonal equation. We propose to rely on polynomial chaos surrogates of the traveltimes between sources and receivers to alleviate the computational burden of solving the eikonal equation during the sampling stage. In an offline stage, the approach builds a functional approximation of the traveltimes from a set of solutions of the eikonal equation corresponding to a few values of the velocity model parameters selected in their prior range. These surrogates then substitute the eikonal-based predictions in the posterior evaluation, enabling very efficient extensive sampling of Bayesian posterior, for instance, by a Markov Chain Monte Carlo algorithm. We demonstrate the potential of the approach using numerical experiments on the inference of two-dimensional domains with layered velocity models and different acquisition geometries (microseismic and seismic refraction contexts). The results show that, in our experiments, the number of eikonal model evaluations required to construct accurate surrogates of the traveltimes is low. Further, an accurate and complete characterization of the posterior distribution of the velocity model is possible, thanks to the generation of large sample sets at a low cost. Finally, we discuss the extension of the current approach to more realistic velocity models and operational situations.
      PubDate: 2021-09-21
      DOI: 10.1007/s13137-021-00184-0
       
 
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