Flow Characteristics of Lava Flow and Evaluation of Diversion Barriers by Numerical Simulation

DOI Web Site

Bibliographic Information

Other Title
  • Flow Characteristics of Lava Flow and E

Search this article

Description

Although there had been almost no previous studies of simulation methods relating to the planar spread of lava flow, either in Japan or abroad, based on the research results obtained by Ishihara et al.a numerical simulation model has been established as a standard model. This consists of the use as simultaneous equations of the continuous equation for liquids with the equation of motion for a two dimensional unsteady flow to which the law of resistance for Bingham liquids is applied. Numerical simulation assuming the existence of a Bingham liquid requires that the yield stress and viscosity of the liquid be included in the law of resistance. As a result, the accuracy of a simulation largely depends on the accuracy of the estimation of the changes in lava flow viscosity, yield stress, and chemical composition, etc. which will occur in accordance with temperature decline.<br>In the present study, domestic and foreign materials about the physical properties of lava were collected in order to examine the relationships between temperature and viscosity and between temperature and yield stress in lava flow. Two Andrade-type expressions were then introduced, using the liquidus point as a boundary for both the temperature-viscosity and the temperature-yield stress relationships. Using these relational expressions, a simulation was conducted of the LBI lava flow on Izu Oshima Island (1986) to verify the simulation model. In the next step, examples from overseas of countermeasures against lava flow were examined. The existence of a diversion barrier as a countermeasure was then postulated for the above LBI lava flow, and its effectiveness was evaluated while changing its crown height and its angle against the lava flow.

Journal

  • Sabo Gakkaishi

    Sabo Gakkaishi 44 (3), 3-11, 1991

    Japan Society of Erosion Control Engineering

Details 詳細情報について

Report a problem

Back to top