HR: 0800h
AN: V31D-0642    [Abstracts]
TI: GMFIX validation studies of supersonic, turbulent multiphase jets for igneous consequences predictions in the Yucca Mountain Project
AU: * Dartevelle, S
EM: sdart@lanl.gov
AF: Los Alamos National Laboratory, Earth and Environmental Sciences, Los Alamos, NM 87545 United States
AB: Supersonic and multiphase flows are very complex transient flows at all scales (from large geophysical to small laboratory-engineering scales), which make them inherently difficult to both numerically and experimentally model. Hence well-constrained experimental analog data usable for validating numerical models are sparse. However this validation step is critical for modelers to gain confidence in their results, even more so if these results are used for performance assessment of radioactive waste disposal such as at the Yucca Mountain (YM) nuclear waste repository. GMFIX is a multiphase code that has been recently redeveloped to meet the strict quality assurance and validation requirements of YM Project. GMFIX relies on the Implicit Multiphase Formalism in which each phase is modeled as continuum. It solves Navier-Stokes and energy partial differential equations for each phase with appropriate turbulence and interfacial coupling between phases. The turbulence model couples production and dissipation of turbulence between the dispersed and the gas phase in merging together RANS approach of gas turbulence with a kinetic-collisional model for the dusty phase. GMFIX has been validated against analog experiments of supersonic underexpanded gas jets from Ladenburg et al. [1949, Physical Review, 76, 662-677] and matched multiphase turbulent jets from Hishida et al. [1985, Trans. Japan Society of Mechanical Engineers, 51, 2330-2337]. For the supersonic underexpanded jet case, GMFIX displays within 10% (within 1 mm) the exact position of the first Mach disc. In addition, GMFIX displays all the features found in these jets, such as expansion fans, incident and reflected shocks, and subsequent downstream mach discs, which make this code ideal for further investigations of equivalent volcanological phenomena. One of the most challenging aspects is the multiphase nature of turbulence. We also validated GMFIX in comparing the velocity profiles and turbulence quantities against the analog experiments from Hishida.The velocity profiles agree with the analog ones as well as these of production of turbulent quantities. Overall, these validation experiments -although inherently challenging- suggest GMFIX captures the most essential dynamical properties of multiphase and supersonic flows and jets.
DE: 0550 Model verification and validation
DE: 4445 Nonlinear differential equations
DE: 4490 Turbulence (3379, 4568, 7863)
DE: 8400 VOLCANOLOGY
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005