Entropy-based design approach of threshold alluvial channels

Cao, Shuyou; Knight, Donald W.

doi:10.1080/00221689709498408

Cited by 67 publications

(29 citation statements)

References 12 publications

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“…Consequently, the association of entropy with the energy structure of the flow (with its internal energy U) is realized by means of the Gibbs' TdS equation, and the determination of the state variable and its probability density function (as done in the works of Chiu [10], [11] and Cao and Knight [4]) is thus avoided. The energy-related quantity A* which is minimized during the regime formation of an alluvial stream is shown to be the Froude number, Fr.…”

Section: Discussionmentioning

confidence: 99%

“…The entropy concept has already been used by Chiu [11], [10] and Chiu and Said [9] in their determination of shear stress and velocity fields of the flows in open channels. And more recently it was used by Cao and Knight [4] to formulate the cross-section of a "type-S" channel at the critical stage. However, no attempt has been made so far to reveal the meaning of A, on a thermodynamic basis -and the following is such an attempt.…”

Section: A = (A;mentioning

confidence: 99%

“…It is assumed that the flow commences at the time / = 0 in an Bh) (4) [The uniformity mentioned is justified by the fact that most of the natural streams, which are of interest to an engineer, are "long" (L/h > 10-\ say). The justification of steadiness can be explained as follows.…”

Section: Determination Of a (I) Generalmentioning

confidence: 99%

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Computation of regime channel characteristics on thermodynamic basis

Yalin

Silva

2000

Journal of Hydraulic Research

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The present paper concerns the computation of regime channel characteristics in cohesionless alluvium. The computational method proposed rests on the channel formation criterion derived from the thermodynamic principles, and on the expression of the aspect ratio determined in the earlier works of the authors on the basis of zero cross-transport rate at the regime stage. The thermodynamic considerations are based on the first and second laws, and the Gibbs' TdS equation: the alluvial stream is treated as an isolated, uniform system. The regime channel formation process is determined by the flow rate and the physical nature of the materials involved (alluvium and water): the sediment transport rate is viewed as an outcome of the phenomenon rather than as one of its characteristic parameters. The regime channel characteristics computed from the suggested method are compared with field and laboratory data of various sources. RÉSUMÉLa présente publication est relative au calcul des caractéristiques de lits en régime dans les alluvions non cohésives. La methode de calcul que nous proposons repose sur Ie critère de formation du lit derive des principes de la thermodynamique, et sur l'expression du rapport de forme determine par les auteurs dans leurs travaux antérieurs, sur la base d'un taux de transport transversal nul pour Ie niveau de régime. Les considerations thermodynamiques sont basées sur la première et la seconde loi et sur l'équation de Gibbs: Ie cours d'eau alluvial est considéré comme un système isolé et uniforme. Le processus de formation du régime du lit est determine par Ie débit liquide et la nature physique des matériaux constitutifs (les alluvions et l'eau): on considère que le débit solide est un résultat du phénomène plutöt que l'un de ses paramètres caractéristiques. Les caractéristiques de lits en régime calculées selon cette methode sont comparées a des données de terrain et expérimentales d'origines diverses.

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Section: Discussionmentioning

confidence: 99%

Section: A = (A;mentioning

confidence: 99%

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Computation of regime channel characteristics on thermodynamic basis

Yalin

Silva

2000

Journal of Hydraulic Research

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“…Chiu (1987Chiu ( -1989Chiu ( , 1991, Chiu et al (1992Chiu et al ( , 1995a, Cao (1995), Cao and Knight (1995a, b, 1996, 1997a and Araujo and Chaudhry (1998), to name but a few. All of the papers written on the subject follow the same path and have the same starting point as that of Shannon (1948).…”

Section: Introductionmentioning

confidence: 97%

An attempt at using the entropy approach to predict the transverse distribution of boundary shear stress in open channel flow

Sterling

Knight

2002

Stochastic Environmental Research and Risk Assessment (SERRA)

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This paper highlights the similarities between a number of studies which have applied the concept of Shannon's entropy to Hydraulic Engineering. The entropy concept is further developed in an attempt to predict the transverse distribution of boundary shear stress in circular open channels. The approach is also extended and applied to circular channels with a flat bed and trapezoidal channels, and the Lagrange multipliers, k, found by recourse to empirical equations. Doubts are expressed concerning the value of the entropy approach to such problems.

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“…An alternative approach is to use the equilibrium hypsometry relationships for channels (Cao and Knight, 1997) and tidal flats (Friedrichs and Aubrey, 1996) to define the form of the estuary crosssection (see Fig. 2).…”

Section: Idealised Cross-section As a Function Of Tidal Prismmentioning

confidence: 99%

Development and extension of an aggregated scale model: Part 1 – Background to ASMITA

et al. 2016

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Whilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorphological elements such as a tidal flat and tidal channel). Such aggregated or lumped models tend not to represent the processes in detail but rather capture the behaviour at the scale of interest. One such model developed using the concept of an equilibrium concentration is the Aggregated Scale Morphological Interaction between Tidal basin and Adjacent coast (ASMITA). In this paper we provide some new insights into the concepts of equilibrium, and horizontal and vertical exchange that are key components of this modelling approach. In a companion paper, we summarise a range of developments that have been undertaken to extend the original model concept, to illustrate the flexibility and power of the conceptual framework. However, adding detail progressively moves the model in the direction of the more detailed process-based models and we give some consideration to the boundary between the two. Highlights The concept of aggregating model scales is explored and the basis of the ASMITA model is outlined in detail;  The relationship between dispersion as used in fast-scale process-based models and the horizontal exchange used in aggregated models is explored;  The basis for formulating suitable equilibrium relationships is explained;  Alternative ways to include advection and dispersion are examined.

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Entropy-based design approach of threshold alluvial channels

Cited by 67 publications

References 12 publications

Computation of regime channel characteristics on thermodynamic basis

Computation of regime channel characteristics on thermodynamic basis

An attempt at using the entropy approach to predict the transverse distribution of boundary shear stress in open channel flow

Development and extension of an aggregated scale model: Part 1 – Background to ASMITA

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