A Runge Kutta Discontinuous Galerkin-Direct Ghost Fluid (RKDG-DGF) Method to Near-field Early-time Underwater Explosion (UNDEX) Simulations

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dc.contributor.authorPark, Jinwonen
dc.contributor.committeechairBrown, Alan J.en
dc.contributor.committeememberTafti, Danesh K.en
dc.contributor.committeememberHughes, Owen F.en
dc.contributor.committeememberKapania, Rakesh K.en
dc.contributor.committeememberMcCue-Weil, Leigh S.en
dc.contributor.departmentAerospace and Ocean Engineeringen
dc.date.accessioned2014-03-14T20:16:02Zen
dc.date.adate2008-09-22en
dc.date.available2014-03-14T20:16:02Zen
dc.date.issued2008-08-28en
dc.date.rdate2008-09-22en
dc.date.sdate2008-09-08en
dc.description.abstractA coupled solution approach is presented for numerically simulating a near-field underwater explosion (UNDEX). An UNDEX consists of a complicated sequence of events over a wide range of time scales. Due to the complex physics, separate simulations for near/far-field and early/late-time are common in practice. This work focuses on near-field early-time UNDEX simulations. Using the assumption of compressible, inviscid and adiabatic flow, the fluid flow is governed by a set of Euler fluid equations. In practical simulations, we often encounter computational difficulties that include large displacements, shocks, multi-fluid flows with cavitation, spurious waves reflecting from boundaries and fluid-structure coupling. Existing methods and codes are not able to simultaneously consider all of these characteristics. A robust numerical method that is capable of treating large displacements, capturing shocks, handling two-fluid flows with cavitation, imposing non-reflecting boundary conditions (NRBC) and allowing the movement of fluid grids is required. This method is developed by combining numerical techniques that include a high-order accurate numerical method with a shock capturing scheme, a multi-fluid method to handle explosive gas-water flows and cavitating flows, and an Arbitrary Lagrangian Eulerian (ALE) deformable fluid mesh. These combined approaches are unique for numerically simulating various near-field UNDEX phenomena within a robust single framework. A review of the literature indicates that a fully coupled methodology with all of these characteristics for near-field UNDEX phenomena has not yet been developed. A set of governing equations in the ALE description is discretized by a Runge Kutta Discontinuous Galerkin (RKDG) method. For multi-fluid flows, a Direct Ghost Fluid (DGF) Method coupled with the Level Set (LS) interface method is incorporated in the RKDG framework. The combination of RKDG and DGF methods (RKDG-DGF) is the main contribution of this work which improves the quality and stability of near-field UNDEX flow simulations. Unlike other methods, this method is simpler to apply for various UNDEX applications and easier to extend to multi-dimensions.en
dc.description.degreePh. D.en
dc.identifier.otheretd-09082008-132416en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09082008-132416/en
dc.identifier.urihttp://hdl.handle.net/10919/28905en
dc.publisherVirginia Techen
dc.relation.haspartJinwonPark_phd.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectUnderwater Explosion (UNDEX)en
dc.subjectGhost Fluid Method (GFM)en
dc.subjectLevel Set Method (LSM)en
dc.subjectBubbleen
dc.subjectRunge Kutta Discontinuous Galerkin (RKDG)en
dc.subjectMulti-fluiden
dc.subjectCavitationen
dc.titleA Runge Kutta Discontinuous Galerkin-Direct Ghost Fluid (RKDG-DGF) Method to Near-field Early-time Underwater Explosion (UNDEX) Simulationsen
dc.typeDissertationen
thesis.degree.disciplineAerospace and Ocean Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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