Lateral Distributions of Depth-Averaged Velocity in Compound Channels with Submerged Vegetated Floodplains

2014 ◽  
Vol 641-642 ◽  
pp. 288-299
Author(s):  
Ming Wu Zhang ◽  
Chun Bo Jiang ◽  
He Qing Huang
Keyword(s):  
Experimental Data ◽  
Analytical Solution ◽  
Rectangular Channel ◽  
Navier Stokes ◽  
Compound Channel ◽  
Navier Stokes Equation ◽  
Compound Channels ◽  
Vegetated Floodplain ◽  
Vegetation Layer ◽  
Good Agreement

Lateral distributions of depth-averaged velocity in open compound channels with submerged vegetated floodplains are analyzed, based on an analytical solution to the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term included to account for the effects of vegetation. The cases of open channels are: rectangular channel with submerged vegetated corner, and compound channel with submerged vegetated floodplain. The present paper proposes a method for predicting lateral distribution of the depth-averaged velocity with submerged vegetated floodplains. The method is based on a two-layer approach where flow above and through the vegetation layer is described separately. An experiment in compound channel with submerged vegetated floodplain is carried out for the present research. The analytical solutions of the three cases are compared with experimental data. The corresponding analytical depth-averaged velocity distributions show good agreement with the experimental data.

Numerical Modeling of a Static Cavitation Module

2016 ◽  
Vol 817 ◽  
pp. 64-69
Author(s):  
Tatiana Vitenko ◽  
Paweł Droździel ◽  
Nazar Horodysky
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Modelling ◽  
Stokes Equation ◽  
Liquid State ◽  
Software Package ◽  
Navier Stokes ◽  
State Equations ◽  
Navier Stokes Equation ◽  
Good Agreement

This paper presents the results of numerical modelling of cavitation flows in a hydrodynamic module. The simulation was performed using the SolidWorks software package. The computations were made based on the Navier-Stokes equation combined with liquid state equations and empirical dependencies which define liquid parameters. The numerical results are in good agreement with experimental data.

Hydrodynamic Entrance Lengths for Incompressible Laminar Flow in Rectangular Ducts

1960 ◽  
Vol 27 (3) ◽  
pp. 403-409 ◽  
Author(s):  
L. S. Han
Keyword(s):  
Rectangular Channel ◽  
Theoretical Data ◽  
Mathematical Expression ◽  
Smooth Transition ◽  
Navier Stokes ◽  
Entrance Length ◽  
Entire Region ◽  
Navier Stokes Equation ◽  
Pressure Drops ◽  
Aspect Ratios

The problem of determining the hydrodynamic entrance length in a rectangular channel is solved by the method of linearizing the Navier-Stokes equation. The resulting equation is regarded as an equation to generate a mathematical expression for the axial velocity in the entire region, making smooth transition from a uniform profile to the fully developed one. From this expression, the entrance length, defined as where 99 per cent of the fully developed center-line velocity is attained, is calculated for channels of six aspect ratios. The pressure drops are also calculated and presented herein. A comparison is made with the limited amount of experimental and theoretical data.

scholarly journals Simulations of Depth-Averaged Streamwise Velocity of Meandering Compound Channel using TELEMAC Modules

2018 ◽  
Vol 65 ◽  
pp. 07001
Author(s):  
Abdul Haslim Abdul Shukor Lim ◽  
Zulhilmi Ismai ◽  
Mohamad Hidayat Jama ◽  
Md. Ridzuan Makhtar
Keyword(s):  
Stokes Equations ◽  
Computing Time ◽  
Streamwise Velocity ◽  
Main Channel ◽  
Navier Stokes ◽  
Relative Depth ◽  
Compound Channel ◽  
Navier Stokes Equations ◽  
Numerical Tools ◽  
Good Agreement

Capabilities of numerical tools to simulate fluid problems significantly depend on its methods to solve for the Navier-Stokes equations. Different dimensional computing tools using the same horizontal meshes were used to simulate flow conditions inside non- and vegetation meandering compound channel. Both tools give good agreement for simulations of depth-averaged streamwise velocity inside the main channel, but its capabilities vary significantly for simulations on floodplains. Lower relative depth recorded a higher percentage of errors than flow with higher relative depth. Vegetation along the main channel increased the flows complexity especially in the area near the vegetation thus reducing the simulation capabilities of the computing tools. Simulations work by TELEMAC-3D significantly better in the areas with highly dimensional and turbulence conditions. TELEMAC-2D is still useful because of its simplicity and lower computing time and resources required.

Comparison of Partially Averaged Navier–Stokes and Large-Eddy Simulations of the Flow Around a Cuboid Influenced by Crosswind

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Siniša Krajnović ◽  
Per Ringqvist ◽  
Branislav Basara
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Large Eddy Simulations ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Better Than ◽  
Good Agreement ◽  
Near Wall

The paper presents a partially averaged Navier–Stokes (PANS) simulation of the flow around a cuboid influenced by crosswind. The results of the PANS prediction are validated against experimental data and results of a large-eddy simulation (LES) made using the same numerical conditions as PANS. The PANS shows good agreement with the experimental data. The prediction of PANS was found to be better than that of the LES in flow regions where simulations suffered from poor near-wall resolution.

Flow resistance of ice-covered streams

1984 ◽  
Vol 11 (4) ◽  
pp. 815-823 ◽  
Author(s):  
S. P. Chee ◽  
M. R. I. Haggag
Keyword(s):  
Velocity Profile ◽  
Channel Flow ◽  
Flow Resistance ◽  
Ice Cover ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Cross Sectional ◽  
Roughness Elements ◽  
Mixing Length Theory ◽  
Good Agreement

This paper deals with the underlying theory of the hydraulics of channel flow with a buoyant boundary as an ice cover. It commences by developing the velocity distribution in two-dimensional covered channel flow using the Reynolds form of the Navier–Stokes equation in conjunction with the Prandtl – Von Karman mixing length theory. Central to the theory is the division of the channel into two subsections. From the developed velocity profile, the functional relationship for the division surface is obtained. Finally, the composite roughness of the channel is derived.Experimental verification of the developed theory was conducted in laboratory flumes. Seven cross-sectional shapes were utilized. Ice covers were simulated with polyethylene plastic pellets as well as floating plywood boards with roughness elements attached to the underside. Velocity profile and composite roughness measurements made in these flumes were in good agreement with the theoretical equations. The composite roughness relationship derived from the theory is very comprehensive, as it takes into account not only the varying rugosities of the channel and its floating boundary but also the shape of the cross section. Key words: composite roughness, ice cover, flow resistance, velocity profile, buoyant boundary, covered channel.

scholarly journals Analytical Solution of the Time-Dependent Microfluidic Poiseuille Flow in Rectangular Channel Cross-Sections and Its Numerical Implementation in Microsoft Excel

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 67
Author(s):  
Patrick Risch ◽  
Dorothea Helmer ◽  
Frederik Kotz ◽  
Bastian E. Rapp
Keyword(s):  
Analytical Solution ◽  
Cross Section ◽  
Poiseuille Flow ◽  
Exact Analytical Solution ◽  
Rectangular Channel ◽  
Channel Cross Section ◽  
Analysis Tool ◽  
Complex Flow ◽  
Microsoft Excel ◽  
Navier Stokes Equation

We recently demonstrated that the Navier–Stokes equation for pressure-driven laminar (Poiseuille) flow can be solved in any channel cross-section using a finite difference scheme implemented in a spreadsheet analysis tool such as Microsoft Excel. We also showed that implementing different boundary conditions (slip, no-slip) is straight-forward. The results obtained in such calculations only deviated by a few percent from the (exact) analytical solution. In this paper we demonstrate that these approaches extend to cases where time-dependency is of importance, e.g., during initiation or after removal of the driving pressure. As will be shown, the developed spread-sheet can be used conveniently for almost any cross-section for which analytical solutions are close-to-impossible to obtain. We believe that providing researchers with convenient tools to derive solutions to complex flow problems in a fast and intuitive way will significantly enhance the understanding of the flow conditions as well as mass and heat transfer kinetics in microfluidic systems.

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