Journal ArticleDOI
On inducing equations for vegetation resistance
Martin J. Baptist,Vladan Babovic,J. Rodríguez Uthurburu,Maarten Keijzer,R.E. Uittenbogaard,Arthur E. Mynett,A. Verwey +6 more
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In this paper, the authors describe the process of induction of equations for the description of vegetation-induced roughness from several angles, and present a numerical 1-DV k-e turbulence model which includes several important features related to the influence plants exhibit on the flow.Abstract:
The paper describes the process of induction of equations for the description of vegetation-induced roughness from several angles. Firstly, it describes two approaches for obtaining theoretically well-founded analytical expressions for vegetation resistance. The first of the two is based on simplified assumptions for the vertical flow profile through and over vegetation, whereas the second is based on an analytical solution to the momentum balance for flow through and over vegetation. In addition to analytical expressions the paper also outlines a numerical 1-DV k–e turbulence model which includes several important features related to the influence plants exhibit on the flow. Last but not least, the paper presents a novel way of applying genetic programming to the results of the 1-DV model, in order to obtain an expression for roughness based on synthetic data. The resulting expressions are evaluated and compared with an independent data set of flume experimentsread more
Citations
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Journal ArticleDOI
Hydrodynamics of vegetated channels
TL;DR: In this article, the authors highlight some recent trends in vegetation hydrodynamics, focusing on conditions within channels and spanning spatial scales from individual blades, to canopies or vegetation patches, to the channel reach.
Journal ArticleDOI
Sorting out river channel patterns.
TL;DR: In this article, the authors have been unable to obtain dynamic meandering in laboratory experiments and in physics-based models that can also produce braiding, which reflects our lack of understanding of what causes the different river patterns.
Journal ArticleDOI
From the blade scale to the reach scale: A characterization of aquatic vegetative drag
Mitul Luhar,Heidi Nepf +1 more
TL;DR: In this paper, a two-layer model is proposed to predict vegetation velocities for fully developed flows through submerged patches of vegetation, where the velocity of the flow is predicted using a constant friction factor.
Journal ArticleDOI
Analytical solution of the depth-averaged flow velocity in case of submerged rigid cylindrical vegetation
Abstract: A new model for the depth-averaged velocity for flow in presence of submerged vegetation is developed. The model is based on a two-layer approach, where flow above and through the vegetation layer is described separately. Vegetation is treated as a homogeneous field of identical cylindrical stems, and the flow field is considered stationary and uniform. It is demonstrated that scaling considerations of the bulk flow field can be used to avoid complications associated with smaller scale flow processes and that still the behavior of depth-averaged flow over vegetation is described accurately. The derived scaling expression of the average flow field is simple in form, it follows fundamental laws of fluid flow, and it shows very good agreement with laboratory flume experiments. The new model can be used for quick evaluation of a river’s hydraulic response in cases where vegetated floodplains are inundated.
Journal ArticleDOI
Floodplain roughness parameterization using airborne laser scanning and spectral remote sensing
TL;DR: In this paper, the authors presented a method of automated roughness parameterization based on manually delineated floodplain vegetation types, schematized as cylindrical elements of which the height (m) and the vertical density (the projected plant area in the direction of the flow per unit volume, m−1) have to be assigned using a lookup table.
References
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Genetic Programming: On the Programming of Computers by Means of Natural Selection
TL;DR: This book discusses the evolution of architecture, primitive functions, terminals, sufficiency, and closure, and the role of representation and the lens effect in genetic programming.
Journal ArticleDOI
The numerical computation of turbulent flows
Brian Launder,D. B. Spalding +1 more
TL;DR: In this paper, the authors present a review of the applicability and applicability of numerical predictions of turbulent flow, and advocate that computational economy, range of applicability, and physical realism are best served by turbulence models in which the magnitudes of two turbulence quantities, the turbulence kinetic energy k and its dissipation rate ϵ, are calculated from transport equations solved simultaneously with those governing the mean flow behaviour.
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The Atmospheric Boundary Layer
TL;DR: In this article, the atmospheric boundary layer (ABLBP) is used to model the ABL and the impact of ABL on climate, including its effect on mean and fluctuating quantities.
Journal ArticleDOI
Flow structure in depth-limited, vegetated flow
Heidi Nepf,Enrique R. Vivoni +1 more
TL;DR: In this paper, the transition between submerged and emergent regimes is described based on three aspects of canopy flow: mean momentum, turbulence, and exchange dynamics, and the observations suggest that flow within an aquatic canopy may be divided into two regions.
Journal ArticleDOI
Mixing layers and coherent structures in vegetated aquatic flows
Marco Ghisalberti,Heidi Nepf +1 more
TL;DR: In this article, the authors demonstrate that the flow structure within and just above an unconfined canopy more strongly resembles a mixing layer than a boundary layer, and demonstrate the applicability of the mixing layer analogy to aquatic systems.