Abstract
Cooling and dynamics of lava flowing in a rectangular channel driven by the gravity force is numerically modeled. The purpose is to evaluate the thermal process as a function of time involving the liquid lava in contact with the solid boundary that flanks lava. Lava rheology is dependent on temperature and strain rate according to a power law function. The model couples dynamics and thermodynamics inside the lava channel and describes the thermal evolution of the solid boundary enclosing the channel. Numerical tests indicate that the solution of the thermo-dynamical problem is independent of the mesh. The boundary condition at the ground and at the levees is treated assuming a solid boundary around the lava flow across which lava can exchange heat by conduction. A far field thermal boundary condition allows to overcome the assumption of constant temperature or constant heat flow as boundary conditions, providing more realistic results. The effect of viscous heating is evaluated and discussed .
Highlights
IntroductionLaboratory studies have extensively demonstrated that lava rheology under certain conditions including vesicularity [Stein and Spera, 1992; Badgassarov and Pinkerton, 2004], crystalline concentration [Pinkerton and Stevenson, 1992; Smith, 2000; Sonder et al, 2006; Champallier et al, 2008] and in a certain temperature range [Shaw et al, 1968] assumes non-Newtonian pseudoplastic properties
Laboratory studies have extensively demonstrated that lava rheology under certain conditions including vesicularity [Stein and Spera, 1992; Badgassarov and Pinkerton, 2004], crystalline concentration [Pinkerton and Stevenson, 1992; Smith, 2000; Sonder et al, 2006; Champallier et al, 2008] and in a certain temperature range [Shaw et al, 1968] assumes non-Newtonian pseudoplastic properties.When the problem of lava flowing under the effect of gravity is resolved, the power law rheology introduces a non-linearity in the diffusion term of the momentum equation and an analytical solution of the differential equations governing the motion does not exist
The purpose of this work is to investigate how the choice of boundary conditions may affect the results of a model of a channeled lava flow, in particular by evaluating the importance of the viscous dissipation term
Summary
Laboratory studies have extensively demonstrated that lava rheology under certain conditions including vesicularity [Stein and Spera, 1992; Badgassarov and Pinkerton, 2004], crystalline concentration [Pinkerton and Stevenson, 1992; Smith, 2000; Sonder et al, 2006; Champallier et al, 2008] and in a certain temperature range [Shaw et al, 1968] assumes non-Newtonian pseudoplastic properties. When the problem of lava flowing under the effect of gravity is resolved, the power law rheology introduces a non-linearity in the diffusion term of the momentum equation and an analytical solution of the differential equations governing the motion does not exist. The need to solve numerically the thermo-dynamic equations describing the flows of a fluid as complex as lava. Despite the great progress made in numerical modeling, it is necessary to assume some simplifying hypotheses
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
