The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform

Majid S Hassanizadeh - One of the best experts on this subject based on the ideXlab platform.

  • a unifying framework for watershed thermodynamics balance Equations for Mass momentum energy and entropy and the second law of thermodynamics
    Advances in Water Resources, 1998
    Co-Authors: Paolo Reggiani, Murugesu Sivapalan, Majid S Hassanizadeh
    Abstract:

    Abstract The basic aim of this paper is to formulate rigorous conservation Equations for Mass, momentum, energy and entropy for a watershed organized around the channel network. The approach adopted is based on the subdivision of the whole watershed into smaller discrete units, called representative elementary watersheds (REW), and the formulation of conservation Equations for these REWs. The REW as a spatial domain is divided into five different subregions: (1) unsaturated zone; (2) saturated zone; (3) concentrated overland flow; (4) saturated overland flow; and (5) channel reach. These subregions all occupy separate volumina. Within the REW, the subregions interact with each other, with the atmosphere on top and with the groundwater or impermeable strata at the bottom, and are characterized by typical flow time scales. The balance Equations are derived for water, solid and air phases in the unsaturated zone, water and solid phases in the saturated zone and only the water phase in the two overland flow zones and the channel. In this way REW-scale balance Equations, and respective exchange terms for Mass, momentum, energy and entropy between neighbouring subregions and phases, are obtained. Averaging of the balance Equations over time allows to keep the theory general such that the hydrologic system can be studied over a range of time scales. Finally, the entropy inequality for the entire watershed as an ensemble of subregions is derived as constraint-type relationship for the development of constitutive relationships, which are necessary for the closure of the problem. The exploitation of the second law and the derivation of constitutive Equations for specific types of watersheds will be the subject of a subsequent paper.

Sergiy Skurativskyi - One of the best experts on this subject based on the ideXlab platform.

  • stability and dynamical features of solitary wave solutions for a hydrodynamic type system taking into account nonlocal effects
    Communications in Nonlinear Science and Numerical Simulation, 2014
    Co-Authors: Vsevolod Vladimirov, Czeslaw Ma Czka, Artur Sergyeyev, Sergiy Skurativskyi
    Abstract:

    Abstract We consider a hydrodynamic-type system of balance Equations for Mass and momentum closed by the dynamical equation of state taking into account the effects of spatial nonlocality. We study higher symmetry admitted by this system and establish its non-integrability for the generic values of parameters. A system of ODEs obtained from the system under study through the group theory reduction is investigated. The reduced system is shown to possess a family of the homoclinic solutions describing solitary waves of compression and rarefaction. The waves of compression are shown to be unstable. On the contrary, the waves of rarefaction are likely to be stable. Numerical simulations reveal some peculiarities of solitary waves of rarefaction, and, in particular, the recovery of their shape after the collisions.

Paolo Reggiani - One of the best experts on this subject based on the ideXlab platform.

  • Coupled Equations for Mass and momentum balance in a stream network: theoretical derivation and computational experiments
    Proceedings of the Royal Society of London. Series A: Mathematical Physical and Engineering Sciences, 2001
    Co-Authors: Paolo Reggiani, Murugesu Sivapalan, S.m Hassanizadeh, William G. Gray
    Abstract:

    In previous work by the authors a rigorous procedure for the derivation of global watershedscale balance laws for Mass, momentum, energy and entropy has been pursued. To complement these, a set of ...

  • a unifying framework for watershed thermodynamics balance Equations for Mass momentum energy and entropy and the second law of thermodynamics
    Advances in Water Resources, 1998
    Co-Authors: Paolo Reggiani, Murugesu Sivapalan, Majid S Hassanizadeh
    Abstract:

    Abstract The basic aim of this paper is to formulate rigorous conservation Equations for Mass, momentum, energy and entropy for a watershed organized around the channel network. The approach adopted is based on the subdivision of the whole watershed into smaller discrete units, called representative elementary watersheds (REW), and the formulation of conservation Equations for these REWs. The REW as a spatial domain is divided into five different subregions: (1) unsaturated zone; (2) saturated zone; (3) concentrated overland flow; (4) saturated overland flow; and (5) channel reach. These subregions all occupy separate volumina. Within the REW, the subregions interact with each other, with the atmosphere on top and with the groundwater or impermeable strata at the bottom, and are characterized by typical flow time scales. The balance Equations are derived for water, solid and air phases in the unsaturated zone, water and solid phases in the saturated zone and only the water phase in the two overland flow zones and the channel. In this way REW-scale balance Equations, and respective exchange terms for Mass, momentum, energy and entropy between neighbouring subregions and phases, are obtained. Averaging of the balance Equations over time allows to keep the theory general such that the hydrologic system can be studied over a range of time scales. Finally, the entropy inequality for the entire watershed as an ensemble of subregions is derived as constraint-type relationship for the development of constitutive relationships, which are necessary for the closure of the problem. The exploitation of the second law and the derivation of constitutive Equations for specific types of watersheds will be the subject of a subsequent paper.

Vsevolod Vladimirov - One of the best experts on this subject based on the ideXlab platform.

  • stability and dynamical features of solitary wave solutions for a hydrodynamic type system taking into account nonlocal effects
    Communications in Nonlinear Science and Numerical Simulation, 2014
    Co-Authors: Vsevolod Vladimirov, Czeslaw Ma Czka, Artur Sergyeyev, Sergiy Skurativskyi
    Abstract:

    Abstract We consider a hydrodynamic-type system of balance Equations for Mass and momentum closed by the dynamical equation of state taking into account the effects of spatial nonlocality. We study higher symmetry admitted by this system and establish its non-integrability for the generic values of parameters. A system of ODEs obtained from the system under study through the group theory reduction is investigated. The reduced system is shown to possess a family of the homoclinic solutions describing solitary waves of compression and rarefaction. The waves of compression are shown to be unstable. On the contrary, the waves of rarefaction are likely to be stable. Numerical simulations reveal some peculiarities of solitary waves of rarefaction, and, in particular, the recovery of their shape after the collisions.

William G. Gray - One of the best experts on this subject based on the ideXlab platform.