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analytic-solutions
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Analyzing transient heat and moisture transport surrounding a heat source in unsaturated porous media using the Green's function
, Article Geothermics ; Volume 81 , 2019 , Pages 224-234 ; 03756505 (ISSN) ; Ghasemi Fare, O ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Generally, in most areas, groundwater level is deep and heat sources (e.g., energy piles)are embedded in unsaturated soil media. Therefore, in order to accurately analyze the soil response close to heat sources, both heat and moisture transport in unsaturated soil domain should be considered. Thermal loading changes the moisture content in the porous media. In this study, the energy conservation and mass fluid continuity equations derived from hydrothermal analysis of a partially saturated soil medium are considered in cylindrical coordinate system. To make the analytical solution possible, partial differential equations (PDEs)are turned into ordinary differential equations (ODEs), through...
Pressure and rate transient modeling of multi fractured horizontal wells in shale gas condensate reservoirs
, Article Journal of Petroleum Science and Engineering ; Volume 185 , 2020 ; Taghavinejad, A ; Razghandi, M ; Rahimi Rigi, H ; Moeini, K ; Jamshidi, S ; Sharifi, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Gas condensate production using technology of multi-stage hydraulically fracturing in shale gas condensate reservoirs' horizontal wells is a new topic of unconventional resources studies. Thus, shale gas condensate as a new source of energy can be considered as an important issue for development and further studies. In this work, a semi-analytical solution of gas and oil two-phase flow is presented for pressure transient analysis (PTA) and rate transient analysis (RTA) of a shale gas condensate reservoir's production data. Fluid flow assumption here is flow in a pseudo triple-porosity porous media, which are matrix, natural fractures and adsorbed gas. Adsorbed gas is a form of gas in porous...
Reformulation of Mindlin-Reissner governing equations of functionally graded circular plates
, Article Acta Mechanica ; Volume 198, Issue 3-4 , 2008 , Pages 209-233 ; 00015970 (ISSN) ; Fallah, F ; Sharif University of Technology
2008
Abstract
The governing equations of the first-order shear deformation plate theory for FG circular plates are reformulated into those describing the interior and edge-zone problems. Analytical solutions are obtained for axisymmetric and asymmetric behavior of functionally graded circular plates with various clamped and simply-supported boundary conditions under mechanical and thermal loadings. The material properties are graded through the plate thickness according to a power-law distribution of the volume fraction of the constituents. The results, which are in closed form and suitable for design purposes, are verified with known results in the literature. It is shown that there are two...
Optimum nonlinear model predictive controller design for flyback PFC rectifiers
, Article ISIEA 2010 - 2010 IEEE Symposium on Industrial Electronics and Applications, 3 October 2010 through 5 October 2010 ; October , 2010 , Pages 70-75 ; 9781424476473 (ISBN) ; Abedi, M. R ; Rezaei, K ; IEEE Malaysia Section; IEEE Malaysia Power Electron. (PEL)/; Ind. Electron.(IE)/ Ind. Appl. (IA) Jt. Chapter ; Sharif University of Technology
2010
Abstract
Single-phase ac-dc Power Factor Correction (PFC) rectifiers have attracted considerable attention in recent years due to the adoption of increasingly stringent power quality regulations. In this paper a nonlinear model predictive controller design for a single-phase Flyback PFC rectifier is presented. After approximation of the tracking error in the receding horizon by its Taylor-series expansion to a specified order, an analytic solution to the model predictive control (MPC) is developed and a closed-loop nonlinear predictive controller is introduced. The main advantage of this digital control method is that unity power factor can be achieved over wide input voltage, load current range and...
Analytical study of dissipative solitary waves
, Article Physica Scripta ; Volume 77, Issue 2 , 2008 ; 00318949 (ISSN) ; Emamzadeh, M. M ; Khorasani, S ; Bobin, J. L ; Amrollahi, R ; Sodagar, M ; Khoshnegar, M ; Sharif University of Technology
2008
Abstract
In this paper, the analytical solution to a new class of nonlinear solitons is presented with cubic nonlinearity, subject to a dissipation term arising as a result of a first-order derivative with respect to time, in the weakly nonlinear regime. Exact solutions are found using the combination of the perturbation and Green's function methods up to the third order. We present an example and discuss the asymptotic behavior of the Green's function. The dissipative solitary equation is also studied in the phase space in the non-dissipative and dissipative forms. Bounded and unbounded solutions of this equation are characterized, yielding an energy conversation law for non-dissipative waves....