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A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number./
Author:	Chen, Yang.
Description:	1 online resource (155 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-11(E), Section: B.
Subject:	Naval engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9781369902181

A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number.
Chen, Yang.

A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number. - 1 online resource (155 pages)

Source: Dissertation Abstracts International, Volume: 78-11(E), Section: B.

Thesis (Ph.D.)--University of Michigan, 2017.

Includes bibliographical references

A velocity decomposition method is developed for the solution of three-dimensional, unsteady flows. The velocity vector is decomposed into an irrotational component (viscous-potential velocity) and a vortical component (vortical velocity). The vortical velocity is selected so that it is zero outside of the rotational region of the flow field and the flow in the irrotational region can thus be solely described by the viscous- potential velocity. The formulation is devised to employ both the velocity potential and the Navier-Stokes-based numerical methods such that the field discretization required by the Navier-Stokes solver can be reduced to only encompass the rotational region of the flow field and the number of unknowns that are to be solved by the Navier-Stokes solver is greatly reduced. A higher-order boundary-element method is used to solve for the viscous potential by applying a viscous boundary condition to the body surface. The finite-volume method is used to solve for the total velocity on a reduced domain, using the viscous-potential velocity as the boundary condition on the extent of the domain. The viscous-potential velocity and the total velocity are time dependent due to the unsteadiness in the boundary layer and the wake. A two-way coupling algorithm is developed to tightly couple the two solution procedures in time. The velocity-decomposition-coupled solver developed in this work is used to solve three-dimensional, laminar and turbulent unsteady flows. For turbulent flows, the solver is applied for both Unsteady-Reynolds-Averaging-Navier-Stokes and Large-Eddy-Simulation computations. The solver is demonstrated to be capable of solving problems with realistic geometries. Preliminary results for 3D lifting flow are also presented. By using the velocity-decomposition-coupled solver, the solution can be determined on a greatly reduced domain and have the same accuracy as that calculated by a conventional Navier-Stokes solver on a large domain. For some test cases, the number of unknowns in the computational mesh is reduced up to 50%.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369902181Subjects--Topical Terms:

1185951
Naval engineering.
Index Terms--Genre/Form:

554714
Electronic books.

A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number.
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245 1 2 $a A Velocity Decomposition Approach for Three-Dimensional Unsteady Viscous Flow at High Reynolds Number.
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500 $a Source: Dissertation Abstracts International, Volume: 78-11(E), Section: B.
500 $a Adviser: Kevin John Maki.
502 $a Thesis (Ph.D.)--University of Michigan, 2017.
504 $a Includes bibliographical references
520 $a A velocity decomposition method is developed for the solution of three-dimensional, unsteady flows. The velocity vector is decomposed into an irrotational component (viscous-potential velocity) and a vortical component (vortical velocity). The vortical velocity is selected so that it is zero outside of the rotational region of the flow field and the flow in the irrotational region can thus be solely described by the viscous- potential velocity. The formulation is devised to employ both the velocity potential and the Navier-Stokes-based numerical methods such that the field discretization required by the Navier-Stokes solver can be reduced to only encompass the rotational region of the flow field and the number of unknowns that are to be solved by the Navier-Stokes solver is greatly reduced. A higher-order boundary-element method is used to solve for the viscous potential by applying a viscous boundary condition to the body surface. The finite-volume method is used to solve for the total velocity on a reduced domain, using the viscous-potential velocity as the boundary condition on the extent of the domain. The viscous-potential velocity and the total velocity are time dependent due to the unsteadiness in the boundary layer and the wake. A two-way coupling algorithm is developed to tightly couple the two solution procedures in time. The velocity-decomposition-coupled solver developed in this work is used to solve three-dimensional, laminar and turbulent unsteady flows. For turbulent flows, the solver is applied for both Unsteady-Reynolds-Averaging-Navier-Stokes and Large-Eddy-Simulation computations. The solver is demonstrated to be capable of solving problems with realistic geometries. Preliminary results for 3D lifting flow are also presented. By using the velocity-decomposition-coupled solver, the solution can be determined on a greatly reduced domain and have the same accuracy as that calculated by a conventional Navier-Stokes solver on a large domain. For some test cases, the number of unknowns in the computational mesh is reduced up to 50%.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Naval engineering. $3 1185951
655 7 $a Electronic books. $2 local $3 554714
690 $a 0468
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of Michigan. $b Naval Architecture and Marine Engineering. $3 1186102
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10612084 $z click for full text (PQDT)