scholarly journals Theoretical perspective on the route to turbulence in a pipe

2016 ◽  
Vol 803 ◽  
Author(s):  
D. Barkley
Keyword(s):  
Pipe Flow ◽  
Theoretical Perspective ◽  
Transition Process ◽  
Turbulent Pipe Flow ◽  
Rapid Expansion ◽  
Clear Understanding ◽  
Percolation Transition ◽  
Spatiotemporal Process ◽  
Physical Features ◽  
The Relationship

The route to turbulence in pipe flow is a complex, nonlinear, spatiotemporal process for which an increasingly clear understanding has emerged in recent years. This paper presents a theoretical perspective on the problem, focusing on what can be understood from relatively few physical features and models that encompass these features. The paper proceeds step-by-step with increasing detail about the transition process, first discussing the relationship to phase transitions and then exploiting an even deeper connection between pipe flow and excitable and bistable media. In the end a picture emerges for all stages of the transition process, from transient turbulence, to the onset of sustained turbulence in a percolation transition, to the modest and then rapid expansion of turbulence, ultimately leading to fully turbulent pipe flow.

Post-Soviet Privatization in the Light of the Coase Theorem (Transaction Costs and Governance Costs)

2003 ◽  
pp. 120-136 ◽  
Author(s):  
V. Andreff
Keyword(s):  
Property Rights ◽  
Transaction Costs ◽  
Theoretical Perspective ◽  
Transition Process ◽  
Initial Distribution ◽  
Coase Theorem ◽  
Early Years ◽  
Firm Boundaries ◽  
Governance Costs ◽  
The Relationship

A Coasian theoretical perspective is assumed to be in the background of most post-Soviet economies' privatization drives. The assumption of zero transaction costs underlying the Coase theorem guarantees an efficient reallocation of property rights whatever is their initial distribution. Once this assumption is relaxed, the result predicted by the Coase theorem is less certain and clashes with the nature of the firm as it has been analyzed earlier by Coase himself. This preliminary presentation is used as a critical driver to provide a non-mainstream assessment of privatization objectives in Russia that became so obviously high in the early years of the transition process. A Coasian analysis also helps to figure out the post-privatization firm boundaries and to design in-house restructuring as well as industrial restructuring - between industrial branches. The issue of the firm boundaries is crucial in the relationship between privatization and restructuring. Finally, we come to terms with the analysis of post-privatization property rights and corporate governance and their possible (governance) costs for in-house restructuring. The last section is devoted to an evaluation of standard and non-standard methods of privatization.

Do more structural holes lead to more risk propagation in R&D networks?

2020 ◽  
Vol 58 (1) ◽  
pp. 39-57 ◽  
Author(s):  
Yue Song ◽  
Naiding Yang ◽  
Yanlu Zhang ◽  
Jingbei Wang
Keyword(s):  
Social Capital ◽  
Risk Perception ◽  
Risk Sharing ◽  
Theoretical Perspective ◽  
Tie Strength ◽  
Clear Understanding ◽  
Specific Context ◽  
Structural Holes ◽  
Content Type ◽  
The Relationship

Purpose The purpose of this paper is twofold: first, to explore how the number of structural holes influences the possibility of risk propagation in R&D networks; and second, to investigate how the specific context of tie strength and common cognition moderate the association between structural holes and risk propagation. Design/methodology/approach This study focuses on how structural holes influence risk propagation under the specific context of relationship and cognitive dimension by drawing on social capital theory. Risk sharing and risk perception as mediating variables are employed in the proposed conceptual model. The authors issued questionnaires to managers and R&D personnel participating in R&D projects and collaboration in Shanghai and Jiangsu province through e-mail and face to face. The data were used to carry out multiple regression analysis to test hypotheses. Findings The results show that relationship between structural holes and risk propagation of R&D network is U-shaped. Risk perception and risk sharing partially mediate the relationship between structural holes and risk propagation. Tie strength significantly moderates the relationship between structural holes and risk sharing, but insignificantly moderates the association between structural holes and risk perception. Common cognition significantly moderates the associations between structural holes and risk sharing, and structural holes and risk perception, respectively. Originality/value This study provides a distinctive theoretical perspective for social capital and risk management. It also offers managers a clear understanding of how to reduce or to avoid risk propagation by jointly leveraging the number of structural holes, tie strength and common cognition.

Challenging the Terms of Order: Representations of the Detroit Rebellions, 1967–1968

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Jordan T. Camp
Keyword(s):  
State Violence ◽  
Rapid Expansion ◽  
Capitalist Development ◽  
Civil Structures ◽  
Us History ◽  
Political Struggles ◽  
Stuart Hall ◽  
The Relationship ◽  
The City ◽  
John Clarke

While many analysts have commented on the representation of 1968 campus events and antiwar demonstrations, less attention has been paid to the global significance of the dramatic struggles in industrial Detroit during the period. The meanings of events in the city were intensely fought over. As Stuart Hall, Chas Critcher, Tony Jefferson, John Clarke, and Brian Roberts observed, the events of 1968 were “an act of collective will, the breaks and ruptures stemming from the rapid expansion in the ideology, culture and civil structures of the new capitalism . . . in the form of a ‘crisis of authority.’” In Detroit the crisis of authority was expressed in the form of popular political struggles against racism, state violence, and the contradictions of life in the industrial capitalist city. This article asks and answers the following research questions about the struggle over the meaning of this decisive turning point in US history: What was the relationship between racial ordering, uneven capitalist development, and mass antiracist and class struggles? How did Black working-class organic intellectuals resist and alter hegemonic definitions of the situation? How are the dialectics of insurgency and counterinsurgency to be best theorized during this precise historical conjuncture? 

Particle Destabilization in Turbulent Pipe Flow

1989 ◽  
Vol 21 (6-7) ◽  
pp. 435-442 ◽  
Author(s):  
B. Döll
Keyword(s):  
Pipe Flow ◽  
Reaction Rate ◽  
Turbulent Pipe Flow ◽  
Cationic Polymers ◽  
Flow Conditions ◽  
Polyelectrolyte Adsorption ◽  
Charge Neutralization ◽  
Silica Suspensions ◽  
Kinetics Of ◽  
Turbulent Flow Conditions

Silica suspensions (pH = 6.8) and three different cationic polymers were used to study the kinetics of charge neutralization by polyelectrolyte adsorption. The experiments were performed in a continuous flow pipe reactor under steady state turbulent flow conditions. The charge neutralization was monitored by electrophoretic mobility (EPM) measurements of the suspended particles as a function of time after polyelectrolyte audition. The results show the dependency of the destabilization reaction rate on flow and polymer characteristics.

scholarly journals Intermediate scaling and logarithmic invariance in turbulent pipe flow

2021 ◽  
Vol 913 ◽  
Author(s):  
Sourabh S. Diwan ◽  
Jonathan F. Morrison
Keyword(s):  
Pipe Flow ◽  
Turbulent Pipe Flow

Abstract

scholarly journals Experimental and theoretical progress in pipe flow transition

2008 ◽  
Vol 366 (1876) ◽  
pp. 2671-2684 ◽  
Author(s):  
A.P Willis ◽  
J Peixinho ◽  
R.R Kerswell ◽  
T Mullin
Keyword(s):  
Pipe Flow ◽  
Quantitative Agreement ◽  
Travelling Wave ◽  
Turbulent Pipe Flow ◽  
Transition To Turbulence ◽  
Reynolds Number Flow ◽  
Threshold Amplitude ◽  
Number Flow ◽  
The Stability ◽  
Laminar State

There have been many investigations of the stability of Hagen–Poiseuille flow in the 125 years since Osborne Reynolds' famous experiments on the transition to turbulence in a pipe, and yet the pipe problem remains the focus of attention of much research. Here, we discuss recent results from experimental and numerical investigations obtained in this new century. Progress has been made on three fundamental issues: the threshold amplitude of disturbances required to trigger a transition to turbulence from the laminar state; the threshold Reynolds number flow below which a disturbance decays from turbulence to the laminar state, with quantitative agreement between experimental and numerical results; and understanding the relevance of recently discovered families of unstable travelling wave solutions to transitional and turbulent pipe flow.

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