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Modeling of Complex Behaviors of Submarine Debris Flows

Title: Modeling of Complex Behaviors of Submarine Debris Flows.
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Name(s): Saha, Bikash C. (Bikash Chandra), author
Ye, Ming, (Professor of scientific computing), professor co-directing dissertation
Niedoroda, Alan W., professor co-directing dissertation
Misra, Vasubandhu, 1970-, university representative
Shanbhag, Sachin, committee member
Wang, Xiaoqiang, committee member
Florida State University, degree granting institution
College of Arts and Sciences, degree granting college
Department of Scientific Computing , degree granting department
Type of Resource: text
Genre: Text
Doctoral Thesis
Issuance: monographic
Date Issued: 2017
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource (121 pages)
Language(s): English
Abstract/Description: Submarine debris flows are hazards when they threaten the facilities that are built on sea floor to facilitate submarine transportation. The dynamics of submarine debris flow is simple once the debris material gets in the flow motion and that it can be represented using simple physics. A two-dimensional model with two-layer Bingham fluid representations, SDFlow2D, was developed by using an Eulerian frame of reference to predict the consequences of complex submarine debris flows. The model was viscoplastic in nature based on depth-averaged approximation to the Shallow Water Equations (SWE), and it assumes that the flow consists of a non-deforming upper layer riding on a deforming layer. The model was verified by comparing the numerical solution with experimental observations as well as with an analytical solution. The comparison shows a good agreement with analytical solution and an acceptable agreement with experimental observations. The model was found to be capable of simulating real-word submarine debris flows. The consequence of bed material entrainment is worth studying as this process adds antecedent sediment to the debris flow mass that in turn increases the intensity of hazard. The modeling code SDFlow2D was enhanced by using simple physics to include the capability of computing bed material entrainment. It was assumed that no inertial force was involved in the process, and that the entrainment was instantaneous. The modified SDFlow2D was applied to two idealized cases and to a prognostic case. A total variation diminishing (TVD) scheme with flux limiter was applied with MacCormack predictor-corrector scheme to smooth out the spurious solution near the source area of debris flow. While the TVD scheme served that purpose to some extent, it was not helpful to make the model robust as the computational time was 15 times greater than that of using the code without TVD scheme. The Bayesian inverse modeling was implemented to quantify the Bingham parameters uncertainty. The technique helps find not only the most probable pair of Bingham parameters but also the distribution of the parameters by conducting a small number of model simulations. The overall outcome of the study benefits the deep sea explorers as well as the designers and planners in charge of designing the submarine structures.
Identifier: FSU_2017SP_Saha_fsu_0071E_13595 (IID)
Submitted Note: A Dissertation submitted to the Department of Scientific Computing in partial fulfillment of the Doctor of Philosophy.
Degree Awarded: Spring Semester 2017.
Date of Defense: April 04, 2017.
Keywords: Bayesian Inversion, Deep Sea Geohazard Modeling, Modeling Bed Sediment Entrainment, Sub-Aerial Debris Flow Modeling, Submarine Debris Flow Modeling, Two Layer Bingham Fluid
Bibliography Note: Includes bibliographical references.
Advisory Committee: Ming Ye, Professor Co-Directing Dissertation; Alan W. Niedoroda, Professor Co-Directing Dissertation; Vasubandhu Misra, University Representative; Sachin Shanbhag, Committee Member; Xiaoqiang Wang, Committee Member.
Subject(s): Civil engineering
Ocean engineering
Petroleum -- Geology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_2017SP_Saha_fsu_0071E_13595
Owner Institution: FSU

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Saha, B. C. (B. C. ). (2017). Modeling of Complex Behaviors of Submarine Debris Flows. Retrieved from http://purl.flvc.org/fsu/fd/FSU_2017SP_Saha_fsu_0071E_13595