東華大學圖書館 |

Fluid-Structure Interaction : = Open Siphons, Feynman Sprinkler, and Weather Vane in Thermal Convection.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Fluid-Structure Interaction :/
其他題名:	Open Siphons, Feynman Sprinkler, and Weather Vane in Thermal Convection.
作者:	Wang, Kaizhe.
面頁冊數:	1 online resource (135 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-09, Section: B.
Contained By:	Dissertations Abstracts International84-09B.
標題:	Fluid mechanics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29325221click for full text (PQDT)
ISBN:	9798374418392

Fluid-Structure Interaction : = Open Siphons, Feynman Sprinkler, and Weather Vane in Thermal Convection.
Wang, Kaizhe.

Fluid-Structure Interaction :Open Siphons, Feynman Sprinkler, and Weather Vane in Thermal Convection. - 1 online resource (135 pages)

Source: Dissertations Abstracts International, Volume: 84-09, Section: B.

Thesis (Ph.D.)--New York University, 2023.

Includes bibliographical references

The conventional study of fluid dynamics involves immobile boundaries that separate solid and fluid. However, fluid mechanics and the interaction between fluid and free boundaries are ubiquitous in nature and industrial applications. This thesis aims to address deeper math and physics behind some seemingly simple gadgets and familiar playthings, where the fluid-structure interaction is the essential driver of the dynamics. The issue of reversibility in hydromechanical sprinklers that auto-rotate while ejecting fluid from S-shaped tubes raises fundamental questions that remain unresolved. In Chapter 2, we report on precision experiments that reveal robust and persistent reverse rotation under suction and a model that accounts for the observed motions. We implement an ultra-low friction bearing in an apparatus that allows for free rotation under ejection and suction for a range of flow rates and arbitrarily long times. Flow measurements reveal a rocket-like mechanism shared by the reverse and forward modes that involves angular momentum flux, whose subtle manifestation in the reverse case stems from centrifugal effects for flows in curved conduits. These findings answer Feynman's long-standing question by providing quantitatively accurate explanations of both modes, and they suggest further inquiries into flux-based force generation and the roles of geometry and Reynolds number.In Chapter 3, inspired by the super-rotation of the Earth's solid core, we investigate the dynamics of a free-rotating body as it interacts with the large-scale circulation (LSC) of the Rayleigh-Benard thermal convection in a cylindrical container. A surprising and persistent co-rotation of both the free body and the LSC emerges, breaking the axial symmetry of the system. The co-rotational speed increases monotonically with the intensity of thermal convection, measured by the Rayleigh number Ra, which is proportional to the temperature difference between the heated bottom and cooled top. The rotational direction occasionally and spontaneously reverses, occurring more frequently at higher Ra. The reversal events follow a Poisson process, suggesting the rotation-sustaining mechanism is likely interrupted and reestablished by the background thermal flow fluctuations. It is hoped that our finding provides one feasible solution to the geophysical problem despite the apparent differences in geometry and parameter ranges.In Chapter 4, we experimentally study the Rayleigh-Benard convection of aqueous glycerol solution in a cubic cell with suspensions of rod-like particles made of polydimethylsiloxane. The particles are inertial due to their large thermal expansion coefficient and finite sizes. The thermal expansion coefficient of the particles is three times larger than that of the background fluid. This contrast makes the suspended particles lighter than the local fluid in hot regions and heavier in cold regions. The heat transport is enhanced at relatively large Rayleigh number but reduced at small Ra. We demonstrate that the increase of Nusselt number arises from the particle-boundary layer interactions: the particles act as ``active'' mixers of the flow and temperature fields across the boundary layers.Siphon is widely used as a simple yet effective device to transfer liquid from a high container into a lower container. Flow in the inverted U-shaped tube of a conventional siphon can be established and maintained only if the tube is filled and closed, so that air does not enter. In Chapter 5, we report on siphons that operate entirely open to the atmosphere by exploiting surface tension effects. Such capillary siphoning is demonstrated by paper tissue that bridges two containers and conveys water from the upper to the lower. We introduce a more controlled system consisting of grooves in a wetting solid, formed here by pressing together hook-shaped metallic rods. The dependence of flux on siphon geometry is systematically measured, revealing behavior different from the conventional siphon. The flux saturates when the height difference between the two container's free surfaces is large; it also has a strong dependence on the climbing height from the source container's free surface to the apex. A one-dimensional theoretical model is developed, taking into account the capillary pressure due to surface tension, pressure loss due to viscous friction, and driving by gravity. Numerical solutions are in good agreement with experiments, and the model suggests hydraulic interpretations for the observed flux dependence on geometrical parameters. The operating principle and characteristics of capillary siphoning revealed here can inform biological phenomena and engineering applications related to directional fluid transport. Further, in Chapter 6, we report another open siphon by exploiting soap film. The film is flowing quasi-two-dimensional, running between two supporting parallel metallic strips. The dependence of flow rate on siphon geometry is systematically measured, revealing a nonlinear dependence on the height difference between the source container's free surface and draining point, and a strong dependence on the climbing height. The velocity profile measured over a transverse cross-section is close to a parabolic distribution.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798374418392Subjects--Topical Terms:

528155
Fluid mechanics.
Subjects--Index Terms:

SiphonIndex Terms--Genre/Form:

542853
Electronic books.

Fluid-Structure Interaction : = Open Siphons, Feynman Sprinkler, and Weather Vane in Thermal Convection.
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500 $a Source: Dissertations Abstracts International, Volume: 84-09, Section: B.
500 $a Advisor: Zhang, Jun;Ristroph, Leif.
502 $a Thesis (Ph.D.)--New York University, 2023.
504 $a Includes bibliographical references
520 $a The conventional study of fluid dynamics involves immobile boundaries that separate solid and fluid. However, fluid mechanics and the interaction between fluid and free boundaries are ubiquitous in nature and industrial applications. This thesis aims to address deeper math and physics behind some seemingly simple gadgets and familiar playthings, where the fluid-structure interaction is the essential driver of the dynamics. The issue of reversibility in hydromechanical sprinklers that auto-rotate while ejecting fluid from S-shaped tubes raises fundamental questions that remain unresolved. In Chapter 2, we report on precision experiments that reveal robust and persistent reverse rotation under suction and a model that accounts for the observed motions. We implement an ultra-low friction bearing in an apparatus that allows for free rotation under ejection and suction for a range of flow rates and arbitrarily long times. Flow measurements reveal a rocket-like mechanism shared by the reverse and forward modes that involves angular momentum flux, whose subtle manifestation in the reverse case stems from centrifugal effects for flows in curved conduits. These findings answer Feynman's long-standing question by providing quantitatively accurate explanations of both modes, and they suggest further inquiries into flux-based force generation and the roles of geometry and Reynolds number.In Chapter 3, inspired by the super-rotation of the Earth's solid core, we investigate the dynamics of a free-rotating body as it interacts with the large-scale circulation (LSC) of the Rayleigh-Benard thermal convection in a cylindrical container. A surprising and persistent co-rotation of both the free body and the LSC emerges, breaking the axial symmetry of the system. The co-rotational speed increases monotonically with the intensity of thermal convection, measured by the Rayleigh number Ra, which is proportional to the temperature difference between the heated bottom and cooled top. The rotational direction occasionally and spontaneously reverses, occurring more frequently at higher Ra. The reversal events follow a Poisson process, suggesting the rotation-sustaining mechanism is likely interrupted and reestablished by the background thermal flow fluctuations. It is hoped that our finding provides one feasible solution to the geophysical problem despite the apparent differences in geometry and parameter ranges.In Chapter 4, we experimentally study the Rayleigh-Benard convection of aqueous glycerol solution in a cubic cell with suspensions of rod-like particles made of polydimethylsiloxane. The particles are inertial due to their large thermal expansion coefficient and finite sizes. The thermal expansion coefficient of the particles is three times larger than that of the background fluid. This contrast makes the suspended particles lighter than the local fluid in hot regions and heavier in cold regions. The heat transport is enhanced at relatively large Rayleigh number but reduced at small Ra. We demonstrate that the increase of Nusselt number arises from the particle-boundary layer interactions: the particles act as ``active'' mixers of the flow and temperature fields across the boundary layers.Siphon is widely used as a simple yet effective device to transfer liquid from a high container into a lower container. Flow in the inverted U-shaped tube of a conventional siphon can be established and maintained only if the tube is filled and closed, so that air does not enter. In Chapter 5, we report on siphons that operate entirely open to the atmosphere by exploiting surface tension effects. Such capillary siphoning is demonstrated by paper tissue that bridges two containers and conveys water from the upper to the lower. We introduce a more controlled system consisting of grooves in a wetting solid, formed here by pressing together hook-shaped metallic rods. The dependence of flux on siphon geometry is systematically measured, revealing behavior different from the conventional siphon. The flux saturates when the height difference between the two container's free surfaces is large; it also has a strong dependence on the climbing height from the source container's free surface to the apex. A one-dimensional theoretical model is developed, taking into account the capillary pressure due to surface tension, pressure loss due to viscous friction, and driving by gravity. Numerical solutions are in good agreement with experiments, and the model suggests hydraulic interpretations for the observed flux dependence on geometrical parameters. The operating principle and characteristics of capillary siphoning revealed here can inform biological phenomena and engineering applications related to directional fluid transport. Further, in Chapter 6, we report another open siphon by exploiting soap film. The film is flowing quasi-two-dimensional, running between two supporting parallel metallic strips. The dependence of flow rate on siphon geometry is systematically measured, revealing a nonlinear dependence on the height difference between the source container's free surface and draining point, and a strong dependence on the climbing height. The velocity profile measured over a transverse cross-section is close to a parabolic distribution.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Fluid mechanics. $3 528155
650 4 $a Plasma physics. $3 3175417
653 $a Siphon
653 $a Thermal convection
653 $a Fluid dynamics
653 $a Large-scale circulation
653 $a Flux
653 $a Fluid-structure interaction
653 $a Hydromechanical sprinklers
655 7 $a Electronic books. $2 lcsh $3 542853
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690 $a 0759
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a New York University. $b Physics. $3 3180022
773 0 $t Dissertations Abstracts International $g 84-09B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29325221 $z click for full text (PQDT)