scholarly journals A semi coupled shallow water model for vertical velocity distribution in an open channel with submerged flexible vegetation

2021 ◽  
Author(s):  
Anupal Baruah ◽  
Arup Kumar Sarma ◽  
Gilbert Hinge
Keyword(s):  
Velocity Profile ◽  
Shallow Water ◽  
Vertical Velocity ◽  
Open Channel ◽  
Model Performance ◽  
Free Water ◽  
Water Model ◽  
Splitting Technique ◽  
Flexible Vegetation ◽  
Vertical Velocity Profile

Abstract Flow-vegetation interactions modify the instream roughness and flow characteristics in the river and estuaries. This study proposes a new quasi three-dimensional hydrodynamic framework to compute the vertical velocity profile in an open channel having submerged flexible vegetation. A modified form of two-dimensional depth-averaged shallow water equations coupled with vegetal drag forces is derived and applied in the simulation. The explicit second-order accurate TVD McCormack predictor-corrector finite difference method with operator splitting technique is used to solve the governing equations in MATLAB. The TVD approach is robust and gives accurate results free from numerical oscillations. The bending profile of the flexible stems under various flow events is calculated from the cantilever beam theory. The vertical velocity profile in the vegetation layer and the free water layer is estimated from Reynold's stress equation and Shannon's entropy theory. The present model is used to replicate some popular experimental test cases. Results indicate a conservative and robust model performance under different flow conditions and patch density. Quantitative analysis of the predicted results is carried out using two statistical indices and found satisfactory.

scholarly journals PRELIMINARY STUDY OF HORIZONTAL AND VERTICAL WIND PROFILE OF QUASI-LINEAR CONVECTIVE UTILIZING WEATHER RADAR OVER WESTERN JAVA REGION, INDONESIA

2019 ◽  
Vol 15 (2) ◽  
pp. 177
Author(s):  
Abdullah Ali ◽  
Riris Adrianto ◽  
Miming Saepudin
Keyword(s):  
Velocity Profile ◽  
Vertical Velocity ◽  
Wind Shear ◽  
Vertical Wind Shear ◽  
Convective Cloud ◽  
Vertical Wind ◽  
Squall Line ◽  
Vertical Velocity Profile ◽  
Preliminary Study ◽  
Wind Profiles

One of the weather phenomena that potentially cause extreme weather conditions is the linear-shaped mesoscale convective systems, including squall lines. The phenomenon that can be categorized as a squall line is a convective cloud pair with the linear pattern of more than 100 km length and 6 hours lifetime. The new theory explained that the cloud system with the same morphology as squall line without longevity threshold. Such a cloud system is so-called Quasi-Linear Convective System (QLCS), which strongly influenced by the ambient dynamic processes, include horizontal and vertical wind profiles. This research is intended as a preliminary study for horizontal and vertical wind profiles of QLCS developed over the Western Java region utilizing Doppler weather radar. The following parameters were analyzed in this research, include direction pattern and spatial-temporal significance of wind speed, divergence profile, vertical wind shear (VWS) direction, and intensity profiles, and vertical velocity profile. The subjective and objective analysis was applied to explain the characteristics and effects of those parameters to the orientation of propagation, relative direction, and speed of the cloud system’s movement, and the lifetime of the system. Analysis results showed that the movement of the system was affected by wind direction and velocity patterns. The divergence profile combined with the vertical velocity profile represents the inflow which can supply water vapor for QLCS convective cloud cluster. Vertical wind shear that effect QLCS system is only its direction relative to the QLCS propagation, while the intensity didn’t have a significant effect.

scholarly journals Implications of the form of the Flow Law for Vertical Velocity and Age–Depth Profiles in Polar Ice

1986 ◽  
Vol 32 (112) ◽  
pp. 366-370 ◽  
Author(s):  
E.W. Wolff ◽  
C.S.M. Doake
Keyword(s):  
Velocity Profile ◽  
Depth Profile ◽  
Vertical Velocity ◽  
Experimental Error ◽  
Ice Sheet ◽  
Polar Ice ◽  
Depth Profiles ◽  
Devon Island ◽  
Vertical Velocity Profile ◽  
Flow Law

AbstractTwo situations are studied in relation to the flow law of polar ice. In each case, models are used with a flow-law exponent of one, and with the more traditional exponent of three. The horizontal velocity profile at Devon Island, Arctic Canada, is better fitted byn= 1; for the vertical velocity profile,n= 3 gives a better fit, but both model profiles fall well within experimental error. For the Camp Century age–depth profile, onlyn= 1 gives an acceptable fit when temperature is allowed for. The large discrepancy between isothermal and non-isothermal models forn= 3 shows the importance of allowing for temperature in studies of ice-sheet properties.

Study on the Two Patters of Vertical Velocity Profile of Tidal Current and Their Law in Estuary and Coastal Waters

2009 ◽  
Author(s):  
Zhihui Ni ◽  
Zhiyao Song
Keyword(s):  
Fractal Dimension ◽  
Velocity Profile ◽  
Vertical Velocity ◽  
Coastal Waters ◽  
Tidal Current ◽  
Surface Wind ◽  
Surface Flow ◽  
Sea Surface ◽  
Vertical Velocity Profile ◽  
Cubic Function

Many scholars at home and abroad have studied tidal velocity profile in estuarine and coastal waters. The results show that velocity profile of tidal current often deviated obviously from the traditional logarithmic profile, due to the flow including wind-driven current, wave-driven current, salinity and so on. In estuarine waters, runoff should be included as a component. In this paper, two patters of vertical velocity profile of tidal current are firstly divided, that are monotone increasing I-velocity profile (during flood tide and ebb tide stage) and non-monotone increasing II -velocity profile (during slack tide stage). Then, by use of variable fractal dimension to obtain the law of II-velocity profile, the results show that: (1)The II -velocity vertical profile does express a first-order accumulated variable-dimensional fractal phenomenon. (2) Through of the fractal dimension, the various formula fitting II-velocity profile were compared, and the results showed that, in practical applications of engineering, cubic function formula is the best fit as the measured data have been verified. Finally, the cubic function formula is applied to flow separation of II -velocity measured in Yangtze River. By the easily separation of the measured flow, we can not only get a reasonable surface flow velocity, such as wind-driven current, runoff, salinity, as well as their driving force weight in the hydrodynamic of estuarine and coastal waters, but also gain the data of bed roughness length and sea surface wind speed, providing reasonable border conditions of the seabed and sea surface for the hydrodynamic numerical simulation in estuarine and coastal waters.

scholarly journals Forcing for a Cascaded Lattice Boltzmann Shallow Water Model

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 439 ◽  
Author(s):  
Sara Venturi ◽  
Silvia Di Francesco ◽  
Martin Geier ◽  
Piergiorgio Manciola
Keyword(s):  
Shallow Water ◽  
Lattice Boltzmann ◽  
Model Performance ◽  
Lattice Boltzmann Model ◽  
Water Model ◽  
Two Dimensional ◽  
Shallow Water Model ◽  
Basic Scheme ◽  
Order Scheme ◽  
Boltzmann Model

This work compares three forcing schemes for a recently introduced cascaded lattice Boltzmann shallow water model: a basic scheme, a second-order scheme, and a centred scheme. Although the force is applied in the streaming step of the lattice Boltzmann model, the acceleration is also considered in the transformation to central moments. The model performance is tested for one and two dimensional benchmarks.

Active layer slope movement in a continuous permafrost environment, Garry Island, Northwest Territories, Canada

1981 ◽  
Vol 18 (11) ◽  
pp. 1666-1680 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Velocity Profile ◽  
Active Layer ◽  
Vertical Velocity ◽  
Late Summer ◽  
Organic Layer ◽  
Field Investigations ◽  
Permafrost Environment ◽  
Vertical Velocity Profile ◽  
Ice Wedge ◽  
Ice Content

Field investigations have been carried out at Garry Island, N.W.T. for the 1964–1980 period in order to study downslope active layer movement at sites with two-sided (downward and upward) freezing and active ice-wedge growth. Movements have been determined with reference to semi-flexible plastic tubes inserted vertically into the ground and by deformation of lines of stakes. The results show that the vertical velocity profile on the hillslopes with clayey hummocks is convex downslope; the movement is plug-like and occurs in late summer; the plug-like movement progressively buries the interhummock peat to form a buried organic layer; and most of the plug-like movement can be attributed to frost creep by thaw of an ice-rich layer at the bottom of the active layer. The ice-rich layer forms by upfreezing in winter and the ice content may be augmented by ice lensing in the summer thaw period. In a sedgy drainage swale, the vertical velocity profile is concave downslope. The active layer of ice-wedge polygons shows a net movement outwards from the centres to the troughs. These studies show that active layer movement at sites with two-sided freezing and active ice-wedge polygons may differ substantially from sites with only one-sided freezing and without active ice-wedge polygons.

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