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Computation of Wall-Bounded Flows Using a New Universal Velocity Profile.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Computation of Wall-Bounded Flows Using a New Universal Velocity Profile./
Author:	Subrahmanyam, Matthew Aaron.
Description:	1 online resource (151 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-06, Section: B.
Contained By:	Dissertations Abstracts International85-06B.
Subject:	Friction. -
Online resource:	click for full text (PQDT)
ISBN:	9798381027440

Computation of Wall-Bounded Flows Using a New Universal Velocity Profile.
Subrahmanyam, Matthew Aaron.

Computation of Wall-Bounded Flows Using a New Universal Velocity Profile. - 1 online resource (151 pages)

Source: Dissertations Abstracts International, Volume: 85-06, Section: B.

Thesis (Ph.D.)--Stanford University, 2023.

Includes bibliographical references

Turbulence has applications in countless engineering, energy and natural systems. As such, it is crucial to be able to understand and predict how flows with turbulence behave as this could lead to enhanced understanding of applications such as atmospheric circulation patterns, blood flow, pollution dispersion in the atmosphere and ocean, combustion and vehicle drag to list only a few.At high Reynolds numbers, solutions of turbulent flows, especially those that are bounded by a wall, remain a computational challenge due to the range of scales that need to be accounted for. As such, it is common to use models to alleviate the need to account for the full range of scales near the wall and help bring about wall-bounded turbulent computational solutions at a much more feasible cost.This work focuses on a new wall model that can be used in both the wall and wake layers of a boundary layer. A boundary layer develops over a wall due to the no-slip at the wall. The wall layer of a turbulent boundary layer includes the viscous sublayer, buffer layer and logarithmic layer. This near-wall region is universal to all smooth wall turbulent flows and is where the most dissipative scales of turbulence lie. The wake layer, however, is where the flow is governed far more by the overall forces that govern the flow and is extremely flow dependent. To date, there is no single theory that unifies all these regions. We seek to provide such a theory with the universal velocity profile.The universal velocity profile is uniformly valid from the wall to the edge of a boundary layer. We use direct numerical simulations, large eddy simulations and experimental data to fit it to channel flow and boundary layers with favorable, zero and adverse pressure gradients and provide a new friction law and a shape function that can be used for high Reynolds number computations.The main focus of the universal velocity profile in this work is as a computational wall model in large eddy simulations. Since it is valid in the wake layer, it can be used freely throughout a boundary layer with assurance that it will give an accurate flow prediction. Large eddy simulations for channel flow with and without a periodic hill and external flow around an airfoil are shown and the universal velocity profile is shown to be robust in its modeling capability.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798381027440Subjects--Topical Terms:

596760
Friction.
Index Terms--Genre/Form:

554714
Electronic books.

Computation of Wall-Bounded Flows Using a New Universal Velocity Profile.
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245 1 0 $a Computation of Wall-Bounded Flows Using a New Universal Velocity Profile.
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500 $a Source: Dissertations Abstracts International, Volume: 85-06, Section: B.
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502 $a Thesis (Ph.D.)--Stanford University, 2023.
504 $a Includes bibliographical references
520 $a Turbulence has applications in countless engineering, energy and natural systems. As such, it is crucial to be able to understand and predict how flows with turbulence behave as this could lead to enhanced understanding of applications such as atmospheric circulation patterns, blood flow, pollution dispersion in the atmosphere and ocean, combustion and vehicle drag to list only a few.At high Reynolds numbers, solutions of turbulent flows, especially those that are bounded by a wall, remain a computational challenge due to the range of scales that need to be accounted for. As such, it is common to use models to alleviate the need to account for the full range of scales near the wall and help bring about wall-bounded turbulent computational solutions at a much more feasible cost.This work focuses on a new wall model that can be used in both the wall and wake layers of a boundary layer. A boundary layer develops over a wall due to the no-slip at the wall. The wall layer of a turbulent boundary layer includes the viscous sublayer, buffer layer and logarithmic layer. This near-wall region is universal to all smooth wall turbulent flows and is where the most dissipative scales of turbulence lie. The wake layer, however, is where the flow is governed far more by the overall forces that govern the flow and is extremely flow dependent. To date, there is no single theory that unifies all these regions. We seek to provide such a theory with the universal velocity profile.The universal velocity profile is uniformly valid from the wall to the edge of a boundary layer. We use direct numerical simulations, large eddy simulations and experimental data to fit it to channel flow and boundary layers with favorable, zero and adverse pressure gradients and provide a new friction law and a shape function that can be used for high Reynolds number computations.The main focus of the universal velocity profile in this work is as a computational wall model in large eddy simulations. Since it is valid in the wake layer, it can be used freely throughout a boundary layer with assurance that it will give an accurate flow prediction. Large eddy simulations for channel flow with and without a periodic hill and external flow around an airfoil are shown and the universal velocity profile is shown to be robust in its modeling capability.
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650 4 $a College football. $3 1474806
650 4 $a Kinematics. $3 792042
650 4 $a Energy. $3 784773
650 4 $a Viscosity. $3 641960
650 4 $a Scale models. $3 1472218
650 4 $a Reynolds number. $3 839681
650 4 $a Entropy. $3 596653
650 4 $a Shear stress. $3 1465445
650 4 $a Fluid mechanics. $3 555551
650 4 $a Mechanics. $3 527684
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