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This paper presents application and tuning of the equilibrated residual method (ERM) of a posteriori error estimation for coupled electromechanical problems of direct, inverse and general piezoelectricity. In these three cases, either electric potential is induced by strains or strains appear due to the applied electric potential or both phenomena occur simultaneously. The mentioned ERM is assigned for the assessment of modeling and approximation errors of the numerical finite element solution. Such error values usually serve as indication for adaptive hierarchical modeling and adaptive mesh changes within thin and/or solid piezoelectric members so as to obtain the solution of assumed accuracy. [ABSTRACT FROM AUTHOR]

We derived a condition under which a coupled system consisting of two finite-dimensional Hamiltonian systems becomes a Hamiltonian system. In many cases, an industrial system can be modeled as a coupled system of some subsystems. Although it is known that symplectic integrators are suitable for discretizing Hamiltonian systems, the composition of Hamiltonian systems may not be Hamiltonian. In this paper, focusing on a property of Hamiltonian systems, that is, the conservation of the symplectic form, we provide a condition under which two Hamiltonian systems coupled with interactions compose a Hamiltonian system. [ABSTRACT FROM AUTHOR]

In this article, we find various kind of solutions of coupled complex modified (KdV) system by using very interesting method binary Darboux transformation. Generally the solutions are classified into zero seed and non-zero seed. In zero seed solutions, we find breather solution and one soliton solution. While in non-zero seed solutions, we obtain bright-bright solitons, w-shaped solitons, bright-dark solitons, periodic and rouge waves solutions. The behavior of these solutions can easily examine from figures. [ABSTRACT FROM AUTHOR]

We observe that a sustained positivity (or negativity) of a system's second-order response will result in a directional change of the system's characteristics under the corresponding random exposure. We identify these changes with improvement (or decline) in the state of a system and introduce the concept of self-improving systems as systems which characteristics can sustainably improve under a random exposure. The resulting framework is of a general phenomenological nature and can be applied to complex systems across different areas of knowledge. [ABSTRACT FROM AUTHOR]

We study a set of coupled oscillators equations describing Alfven's linear coupling and fast magnetosonic waves in a magnetized plasma. Using the methods of asymptotic analysis, we derive analytical expressions for the transformation coefficient, as well as Liouville-Green asymptotic solutions. The obtained results are compared with the mathematically similar Landau-Zener problem in quantum mechanics. [ABSTRACT FROM AUTHOR]

The optical properties of a periodic slit-groove array perforated in a metal film have been studied experimentally and theoretically. Due to the interplay between periodic slits and periodic grooves, a switching from transmission minimum to maximum and the appearance of an additional dip were experimentally observed. To understand the effect, two different theoretical methods, i.e., the phenomenological method and analytical (coupled-mode) method, for studying the peculiar optical properties have been adopted. The results may provide us with new insights into underlying physics of interaction between the sub-wavelength objects and electromagnetic waves. [ABSTRACT FROM AUTHOR]

An implementation of the full explicitly correlated coupled-cluster singles and doubles model CCSD-F12 using a single Slater-type geminal has been obtained with the aid of automated term generation and evaluation techniques. In contrast to a previously reported computer code [T. Shiozaki et al., J. Chem. Phys. 129, 071101 (2008)], our implementation features a reduced dependence on the auxiliary basis set due to the use of a reformulated evaluation of the so-called Z-intermediate rather than straight forward insertion of an auxiliary basis expansion, which allows an unambiguous comparison to more approximate CCSD-F12 models. First benchmark results for total correlation energies and reaction energies indicate an excellent performance of the much cheaper CCSD(F12) model. [ABSTRACT FROM AUTHOR]

With the move to distributed systems and an increasing emphasis on the use of object-orientation for new system design, effective distribution of object-oriented applications is becoming an important concern for designers. Early research in this area has focused on object-clustering schemes for shared memory configurations that have limited value to business applications, which must be distributed over loosely coupled networks. These applications also exhibit the properties of simpler structural relationships and a large number of instances, demanding approaches closer to fragmentation and allocation instead of clustering. This paper develops an approach to distribution of object-oriented applications over geographically dispersed sites in loosely coupled networks---taking account of concerns such as encapsulation, inheritance, messaging, and implicit joins. The approach consists of two phases. First, we develop a scheme for generating class fragments, which ensures that encapsulation is not violated and inheritance is not stretched across sites. Second, considering the message-intensive operation of object-oriented systems, we devise models for allocation of class fragments to sites that minimize inter-site traffic. A nonarbitrary procedure to compile traffic volume estimates exploiting the notion of implicit joins in object-oriented applications provides the natural linkage between the two phases. A research prototype was implemented to establish feasibility of the proposals. We demonstrate usefulness of the approach by its application for distribution of a real-world information system. [ABSTRACT FROM AUTHOR]

Investigates closely related issues regarding potential practical implementation of condensed phase control schemes. Laser control of reactions in solution; Assumption that the laser will not couple to the condensed phase environment; Effect of uncertainty introduced into the controlling pulse; Challenges facing attempts at condensed phase chemical reaction control.

We study, in this paper, a stochastic version of a coupled Allen–Cahn–Navier–Stokes model in a two-dimensional (2D) bounded domain. The model consists of the Navier–Stokes equations (NSEs) for the velocity, coupled with a Allen–Cahn model for the order (phase) parameter. We prove the existence and the uniqueness of a variational solution. [ABSTRACT FROM AUTHOR]

Abstract The three-dimensional (3D) numerical modelling of laminated glass (LG) plate subjected to coupled thermomechanical loading is in the scope of this paper. The method called FEM23 is applied, in which a 2D in-plane mesh is used, however full 3D results are obtained. In any LG plate glass panes are bonded by very thin polymer films. This layered structure consists of subsequent thick and thin layers of glass and polymer, respectively. Additionally, the thermal and mechanical properties of the glass and the bonding polymer are significantly different. FEM23 is suitable for analyses of such kind of structure. The full 3D results of the coupled problem are obtained following special FEM23 postprocessing. FEM23 is a relatively simple, robust and effective method and 3D thermo-mechanical results obtained are correct for both stationary and non-stationary heat transport. The accuracy of the method has been examined with the use of solutions obtained from the ABAQUS system. The examples presented in the article include two-, three- and four-paned LG plates. [ABSTRACT FROM AUTHOR]

Highlights • Analytical formulation of bridge-pedestrian interaction including inter-variability. • A new SDOF pedestrian model reproduces the human gait and transmits contact forces only through compliant and damped legs. • Finite element method adopted to model the 3D geometry of the bridge. • Bridge-pedestrian coupled equations of motion integrated through an iterative procedure. • Loading scenarios include groups of pedestrians with different spatial distributions. Abstract In this work, an analytical formulation for the vibration response of a bridge due to walking pedestrians is proposed to the aim of modelling the human-structure interaction (HSI) in the vertical direction. Bridge and pedestrians are described as mechanical systems having a finite number of degrees of freedom (DOFs). A new single DOF model of a bipedal pedestrian is proposed, that reproduces the alternation of single and double support phases of human gait and the related ground reaction forces. The finite element method is adopted to model the 3D geometry of the bridge. The coupled equations of motion are derived based on the key assumption that contact points between the pedestrians and the bridge deck are massless. However, the structural matrices of the coupled system are time varying due to the pedestrian motion along the bridge. An uncoupled solution strategy is devised to reduce the computational burden, allowing for the separate integration of the bridge and the pedestrian sub-systems. The coupled formulation is uncoupled and associated with an iterative procedure that restores compatibility and equilibrium at contact points. The pedestrian model and the analytical procedure are implemented in a research code where input data are the bridge structural matrices computed with a commercial FE code. The modelling and analysis procedure is applied to a case study, a lively footbridge in Seriate, Italy. A first validation of the code is obtained by comparison with a closed form solution for a 1D beam. For the loading scenarios analyzed here, a maximum of two iterations per step are necessary to achieve convergence within a prescribed tolerance. Loading scenarios encompassing groups of pedestrians in different transverse positions highlight the importance of the 3D bridge modelling. The comparison with a few experimental results clarifies the role of the modelling assumptions. Conclusions discuss novelties, advantages, limits and future developments of the proposed approach. [ABSTRACT FROM AUTHOR]

Highlights • A mechanism to evaluate the MS's vulnerability under threats is proposed. • The indices of topological structure vulnerability and the functional vulnerability are given. • The multidimensional spatial computing model of vulnerability is build. Abstract The safe operation requirement for an enterprise depends significantly on the uninterrupted and reliable functioning of its manufacturing system (MS). However, this system is frequently subjected to different disturbances and destructions, such as safety accidents, equipment fault, and misoperation. Therefore, a sophisticated evaluation mechanism and an effective alleviation design for the vulnerability of a MS are of great importance for the reliable functioning of the MS. This study proposes a detailed methodology to comprehensively assess the vulnerability of a MS subject to different disturbances by using complex networks and simulation technology. The proposed methodology includes a complex network expression for the MS, a description of the equipment failure scenarios, a method to analyze the vulnerability of the MS, and an evaluation method to quantify the vulnerability value. The vulnerability of a MS is evaluated in terms of its work, including the topological structure vulnerability and function vulnerability. Different vulnerability metrics are described, and the vulnerability information is quantified by the multidimensional spatial computing method. Subsequently, the effectiveness of the proposed method is validated in the engineering assembly manufacturing system (EAMS). [ABSTRACT FROM AUTHOR]

The formal theory is presented for calculating the analytic first derivative of the energy with respect to arbitrary perturbations within the equation-of-motion coupled-cluster (EOM-CC) approximation. Through use of the Dalgarno–Stewart interchange theorem (Z-vector method), terms involving derivatives of the ground state cluster amplitudes are eliminated, leading to the definition of a new quasiparticle de-excitation operator which simplifies the theory and significantly reduces the expected cost associated with studying potential energy surfaces for excited electronic states. For both illustrative and pragmatic reasons, the final equations are cast in a form similar to that developed for ground state CC energy derivatives, involving contraction of effective one- and two-particle density matrices with matrix elements of the differentiated Hamiltonian. Some aspects regarding calculation of the gradient are discussed with particular attention devoted to similarities between the structure of the present formulas and those which have been previously implemented for the ground state problem. [ABSTRACT FROM AUTHOR]

This paper develops a closed-loop coupled fault estimation and a multivariable resilient control for high-speed train traction rectifier with upset conditions. By treating the multidimensional adverse states as changes of a single faults evolution factor, we build a reduced dimensional MIMO evolution model satisfying persistently exciting condition. In the presence of coupled faults, a nominal feed-forward controller guarantees the reliability of the closed-loop stability. Then, a fast proportional integral fault estimator is employed to predict the system resilience within a few microseconds. Under system uncertainties, a fault tolerant control scheme, including a unified robust adaptive controller, is designed to enhance the reliability. Applying the conditions of the globally asymptotically stability, the convergence of the resilient system is rigorously proved. A case study is performed to verify the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: The problem of stable equilibrium of a Bernoulli-Euler beam with both ends fixed positioned in an electrostatic field under the action of a pulse laser is considered. The initial equilibrium position under the action of the electrostatic field has been obtained. It has been shown that there exist either two equilibrium positions of this kind—stable and unstable ones—or none in a sufficiently strong electric field. The temperature field in the beam under the action of a laser pulse has been found. The possibility to lose the stability of equilibrium under heating of the element by a laser pulse is suggested for the first time. Regions corresponding to the stability of the aforesaid equilibrium position in the space of pulse parameters have been determined. [ABSTRACT FROM AUTHOR]

The semi-analytical transient solutions of fully thermomechanical coupling for sliding contact have been deduced by using the plane-point heat source equivalent method, the thermoelastic displacement potential and the central difference method. To improve the calculated efficiency, the discrete convolution and fast Fourier transform are applied. The effects of coupled term, sliding velocity, frictional coefficient and initial temperature on temperature rise and the influence of thermal behavior on stress are studied. Results indicate that the coupled term can significantly affect the temperature rise for high velocity and it can be ignored for low velocity; the temperature rise is sensitive to the sliding velocity and the frictional coefficient; the Mises stress on the contact patch is decreased when considering thermal effect. [ABSTRACT FROM AUTHOR]

In this paper, we study, from the numerical point of view, a porous thermoviscoelastic mixture problem. The mechanical problem is written as a linear coupled system of two hyperbolic partial differential equations for the porosities and a parabolic partial differential equation for the temperature field. An existence and uniqueness result and an energy decay property are stated. Then, fully discrete approximations are introduced by using the finite element method to approximate the spatial variable and the backward Euler scheme to discretize the time derivatives. A priori error estimates are proved from which, under suitable regularity conditions, the linear convergence of the algorithm is derived. Finally, some numerical simulations are presented to demonstrate the accuracy of the approximations in an academical one-dimensional example and the behaviour of the solutions in one- and two-dimensional problems. [ABSTRACT FROM AUTHOR]

Fuzziness or vagueness is an inherent property of decision making process which arises as a result of psychological perspective of human or due to impreciseness in physical nature of problem. Along with this property, another psychological aspect namely non-deterministic nature of decision maker measured by priority index is also closely intrigued with the process of decision making. The purpose of the study is to develop a robust multi-criteria decision making model that considers the non-deterministic nature of decision maker along with the vagueness in decision. In order to capture the both qualities, ratings of alternatives versus criteria are assessed in the form of parametric interval valued intuitionistic fuzzy number (PIVIFN). Moreover, with each decision making model is associated a risk factor for not attaining the global best result. Therefore, in the model, for minimizing the risk associated the decision matrix is converted into relative benefit matrix. In addition to these, an accurate defuzzification method is developed using the Riemann integral method. Different properties, theorems and operators are redefined for PIVIFN. Finally, the model is used for solving a site selection problem. In order to test the feasibility of the proposed model, the same problem is solved by several other established models from the literatures. [ABSTRACT FROM AUTHOR]

Summary: This paper develops the scaled boundary finite element formulation for applications in coupled field problems, in particular, to poroelasticity. The salient feature of this formulation is that it can be applied over arbitrary polygons and/or quadtree decomposition, which is widely employed to traverse between small and large scales. Moreover, the formulation can treat singularities of any order. Within this framework, 2 sets of semianalytical, scaled boundary shape functions are used to interpolate the displacement and the pore fluid pressure. These shape functions are obtained from the solution of vector and scalar Laplacian, respectively, which are then used to discretise the unknown field variables similar to that of the finite element method. The resulting system of equations are similar in form as that obtained using standard procedures such as the finite element method and, hence, solved using the standard procedures. The formulation is validated using several numerical benchmarks to demonstrate its accuracy and convergence properties. [ABSTRACT FROM AUTHOR]

The electrostatically controlled deployable membrane antenna (ECDMA) is a promising space structure due to its low weight, large aperture and high precision characteristics. However, it is an extreme challenge to describe the coupled field between electrostatic and membrane structure accurately. A direct coupled method is applied to solve the coupled problem in this paper. Firstly, the membrane structure and electrostatic field are uniformly described by energy, considering the coupled problem is an energy conservation phenomenon. Then the direct coupled electrostatic-structural field governing equilibrium equations are obtained by energy variation approach. Numerical results show that the direct coupled method improves the computing efficiency by 36% compared with the traditional indirect coupled method with the same level accuracy. Finally, the prototype has been manufactured and tested and the ECDMA finite element simulations show good agreement with the experiment results as the maximum surface error difference is 6%. [ABSTRACT FROM AUTHOR]

The dynamic response of a two-dimensional generalized thermal shock problem is investigated in the context of the fractional order theory of thermoelasticity proposed by Sherief et al. To demonstrate the solution process, a thermoelastic half-space subjected to a thermal shock on its bounding surface is considered in detail. The governing equations for the problem are formulated and then solved by normal mode analysis. The distributions of the considered nondimensional temperature, displacement, and stress are obtained and illustrated graphically. The effect of fractional order parameter on the variations of the considered variables is investigated, and the results show that the fractional order parameter has significant influence on the variations of the considered variables. [ABSTRACT FROM AUTHOR]

Piezoelectric and flexoelectric nanostructures attracted great interest from different research communities for their potential applications as sensors, actuators and energy harvesters. Nevertheless, modeling and analysis of such structures are still under investigation. In fact, strain gradient effects are expected to be nonnegligible at the nanoscale level where they induce substantial variations on the static and dynamic responses of the nanostructure, especially when coupled field behavior are present. Therefore, flexoelectricity which refers to the electromechanical coupling between electrical polarization and mechanical strain gradient, is expected to be dominant at the nanoscale. In this paper, the main focus is to analyze analytically the static and dynamic responses of nanobeams, having different boundary conditions and electrical loads, where gradient elasticity, piezoelectricity and flexoelectricity are taken into account. We develop a complete mathematical model using Hamilton’s principle. The derived governing electromechanical coupled equations and corresponding boundary conditions are solved using a Galerkin procedure based on an assumed mode approach. The principal electromechanical outputs are calculated analytically for actuation and energy harvesting configurations. Bidirectional polarization, electric field and elastic strain gradient effect are taken into account in the developed model. Validation and comparison with previously published results showed that considerable decrease of the performance could be observed because of the introduction of the elastic strain gradient effect. The performance degradation is also more pronounced if the aspect ratio is reduced. [ABSTRACT FROM AUTHOR]

On the basis of a general integral form of the variational principle of the least possible dissipation of energy of the nonequilibrium thermodynamics, we deduce a nonclassical nonsteady heat-conduction equation for multilayer polyreinforced shells of any shape. A method for the determination of the integral heat conductivities of reinforced layers is developed and the effective constitutive equations for the description of its thermoelastic behavior are proposed. A nonclassical model of deformation of the multilayer shell and a nonlinear model of distribution of the heat flux along the thickness of the layer are formulated. This allows us to take into account the transverse shear strains and guarantee the conditions of thermomechanical contact of the layers and the conditions of thermomechanical loading on the face surfaces of the shell. We construct a closed system of differential equations with the corresponding initial and boundary conditions for a coupled problem of thermoelastic deformation of layered composite shells and plates. [ABSTRACT FROM AUTHOR]

We present a brief survey of investigations carried out in recent years by the Lviv scientific school of the mechanics of coupled fields on the problems of construction and generalization of mathematical models and methods aimed at the description, determination, and optimization of the thermomechanical behavior of bodies under the combined action of force, thermal, and electromagnetic loads. [ABSTRACT FROM AUTHOR]

Summary: A methodology for the calculation of gradients with respect to design parameters in general fluid‐structure interaction problems is presented. It is based on fixed‐point iterations on the adjoint variables of the coupled system using algorithmic differentiation. This removes the need for the construction of the analytic Jacobian for the coupled physical problem, which is the usual limitation for the computation of adjoints in most realistic applications. The formulation is shown to be amenable to partitioned solution methods for the adjoint equations. It also poses no restrictions to the nonlinear physics in either the fluid or structural field, other than the existence of a converged solution to the primal problem from which to compute the adjoints. We demonstrate the applicability of this procedure and the accuracy of the computed gradients on coupled problems involving viscous flows with geometrical and material nonlinearities in the structural domain. [ABSTRACT FROM AUTHOR]

Numerical model of combined laser and induction welding is presented and solved. From the physical viewpoint, the process represents a coupled problem of nonlinear and nonstationary interaction of the magnetic and temperature fields respecting the phase change and evaporation of heated molten metal (keyhole effect). A specific algorithm was developed for manipulation with the space and time variation of interface between solid and molten metal. Selected results are compared with the realized experiment. [ABSTRACT FROM AUTHOR]

This article presents a possible inflation scenario as a consequence of non-minimal gravitational couplings in the Conformal Standard Model. The model consists, in comparison to the SM, of additional right-chiral neutrinos and complex scalars coupled to the right-chiral neutrinos but not to the SM particles. The inflation is driven by two non-minimally coupled fields, one being the usual Higgs and the other one of the sterile scalars. It turns out that in this model, the tensor-to-scalar ratio and spectral index can match the current data for a wide range of parameters. [ABSTRACT FROM AUTHOR]

The objective of this paper is to present an original study for optimizing the size of the longitudinal-flux double-sided linear switched reluctance motor (LSRM) under thermal and weight constraints. The performance is evaluated taken into account duty cycle operating conditions and thermal restrictions. The proposed approach couples finite element analysis for magnetic propulsion force computation and lumped-parameter thermal network for thermal transient analysis. The LSRMs design parameters are characterized by the number of phases and by their size denoted by the pole stroke. The operating conditions are the current density, the duty cycle and the admissible temperature rise of the insulation system. The grid search algorithm is used for solving the optimization problem. From the results, with the help of a novel multivariable optimization chart, a set of optimal configurations regarding to miniaturizations and downsizing of LSRMs is provided. [ABSTRACT FROM PUBLISHER]

In this paper, the influence of gap consideration on load identification under various Halbach-array-based topologies (HABOs) is investigated while the system is on-duty. The load characteristics of a radial flux generator with closed-slots and the exterior rotor topology is discussed, where the effect of eddy-currents are observed. This comparative study deals with the consideration of the combined moment of inertia calculation that demonstrates how electromagnetic-based post processing calculations are estimated without the aid of nominal machine parameter values. The analysis was performed using a 2-D finite-element simulation of different HABOs with the gap consideration between the segments. Additionally, a comprehensive comparison with no gap is considered. Also, the dynamic analysis using an uncontrolled conventional rectifier model is used to derive effected key output parameters such as torque, output power, power factor, and line-to-line voltage. The major objective of the study is to determine corresponding load results in order to employ the most suitable and capable magnetization topology from the load perspective in the PM synchronous generator (PMSGs). Accordingly, the maximum power (MP) point was carried out to maximize the output DC power. With respect to the combined moment of inertia estimation, the load parameter estimation is verified experimentally on a surface-mounted PMSG using different magnetization topologies. Furthermore, commercial and environmental issues of the project are considered to reduce CO 2 emissions as part of green power generation development. [ABSTRACT FROM AUTHOR]

We analyze a weak formulation of the coupled problem defining the interaction between a free fluid and a poroelastic structure. The problem is governed by the time-dependent incompressible Navier–Stokes equations and the Biot equations. Under a small data assumption, existence and uniqueness results are proved and a priori estimates are provided. [ABSTRACT FROM AUTHOR]

Anomaly matching constrains low-energy physics of strongly-coupled field theories, but it is not useful at finite temperature due to contamination from high-energy states. The known exception is an 't Hooft anomaly involving one-form symmetries as in pure SU( N ) Yang-Mills theory at θ = π. Recent development about large- N volume independence, however, gives us a circumstantial evidence that 't Hooft anomalies can also remain under circle compactifications in some theories without one-form symmetries. We develop a systematic procedure for deriving an 't Hooft anomaly of the circle-compactified theory starting from the anomaly of the original uncompactified theory without one-form symmetries, where the twisted boundary condition for the compactified direction plays a pivotal role. As an application, we consider $$ {\mathbb{Z}}_N $$ -twisted $$ \mathbb{C}{P}^{N-1} $$ sigma model and massless $$ {\mathbb{Z}}_N $$ -QCD, and compute their anomalies explicitly. [ABSTRACT FROM AUTHOR]

In this paper, we propose a spectral element method (SEM) to study guided waves in coupled problems involving thin-walled structures and fluid-acoustic cavities. The numerical method is based on the subdomain decomposition of the fluid-structure system. Two spectral elements are developed to represent the fluid and the structure. A plate element based on a mixed Reissner-Mindlin and Kirchhoff-Love formulation is proposed to represent the thin-walled structure. This element uses C0 approximation functions to overcome the difficulties to formulate elements with arbitrary order from C 1 functions. The proposed element uses a substitute transverse shear strain field resulting free shear locking. The fluid element is derived from the Helmholtz equation. These elements use Lagrange polynomials as shape functions at the Legendre-Gauss-Lobatto (LGL) points. The analysis is carried out by a two-and-a-half dimension (2.5D) approach in the wavenumber-frequency domain. The guided wave in a fluid cavity with a flexible side is analysed. [ABSTRACT FROM AUTHOR]

Liquid loading is a major operational constraint in mature gas fields around the world. It manifests itself as an increasing back pressure on the reservoir due to a rising liquid column in the well, which initially decreases deliverability, then ultimately causes the gas well to cease production. Theoretically, every gas well will experience this debilitating phenomenon in the latter stages of its producing life. In this paper, both laboratory experiments and numerical simulations are presented to shed more light on the physical process of liquid loading, with a focus on reservoir responses. On the one hand, core-flooding experimental setups of different scales were designed and constructed to investigate back pressure effects on transient flow through the near-wellbore region of the reservoir. On the other hand, the modelling of a gas well undergoing controlled flow and shut-in cycles was performed to validate core-scale observations at reservoir scale, using commercial integrated numerical software that connects a transient wellbore model to a transient reservoir model. The simulated transient characteristics of short-term downhole dynamics (e.g. liquid re-injection and co-current/counter-current flows) supported the U-shaped concept observed in the experiments. The detected temporal distribution of pore fluid pressure within the reservoir medium itself (referred to as the U-shaped pressure profile) was observed both experimentally at the core-scale and numerically at the reservoir-scale. This pressure distribution can be used to explain re-injection of the denser phases into the near-wellbore region of the reservoir. [ABSTRACT FROM AUTHOR]