Michael A. Sprague

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Spectral elements based on Legendre polynomials are used to improve an existing finite-element method for simulating a highly nonlinear field phenomenon: fluid cavitation in an underwater-shock environment. Further improvement is provided by separation of the total field into its equilibrium, incident, and scattered components. These enhancements promise to(More)
In an underwater-shock environment, cavitation, i.e., boiling, occurs as a result of reflection of the shock wave from the free surface and/or wetted structure that causes the pressure in the water to fall below its vapor pressure. If the explosion is sufficiently distant from the structure, the motion of the fluid surrounding the structure may be assumed(More)
In an underwater-shock environment, cavitation (boiling) occurs as a result of reflection of the shock wave from the free surface and/or wetted structure causing the pressure in the water to fall below its vapour pressure. If the explosion is sufficiently distant from the structure, the motion of the fluid surrounding the structure may be assumed small,(More)
with radial throughflow Eric Serre, Michael A. Sprague, and Richard M. Lueptow LMSNM, CNRS—Universités d’Aix-Marseille, IMT, La Jetée-Technopôle de Chtâteau-Gombert, 38 rue Frédéric Joliot-Curie, 13451 Marseille Cedex 20, France School of Natural Sciences, University of California, Merced, California 95344, USA Department of Mechanical Engineering,(More)
When simulating underwater shock problems near a free surface where the charge is sufficiently removed from the structure, the fluid can be modeled with Cavitating Acoustic Finite Elements (CAFE) [1] that are coupled to a finite-element model of the structure. However, it has been demonstrated that the CAFE approach is too computationally expensive for(More)
In this paper we examine the stability and accuracy of numerical algorithms for coupling time-dependent multi-physics modules relevant to computer-aided engineering (CAE) of wind turbines. This work is motivated by an in-progress major revision of FAST, the National Renewable Energy Laboratory’s (NREL’s) premier aero-elastic CAE simulation tool. We employ(More)
A theoretically exact computational boundary is introduced, that is based on modal residual potentials for the spherical geometry. The boundary produces a set of first-order, uncoupled ordinary differential equations for nodal boundary responses, and a set of uncoupled time-stepping equations for modal boundary responses. The two sets are coupled through(More)
Cost-effective production of fuels and chemicals from lignocellulosic biomass often involves enzymatic saccharification, which has been the subject of intense research and development. Recently, a mechanistic model for the enzymatic saccharification of cellulose has been developed that accounts for distribution of cellulose chain lengths, the accessibility(More)
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