scholarly journals Horizontal mixing in shallow flows

2012 ◽  
pp. 51-64
Keyword(s):  
Shallow Flows ◽  
Horizontal Mixing

scholarly journals Horizontal Mixing in Shallow Flows

2005 ◽  
pp. 55-68 ◽  
Author(s):  
Bram C. van Prooijen ◽  
Wim S.J. Uijttewaal
Keyword(s):  
Shallow Flows ◽  
Horizontal Mixing

Grid turbulence in shallow flows

2003 ◽  
Vol 489 ◽  
pp. 325-344 ◽  
Author(s):  
W. S. J. UIJTTEWAAL ◽  
G. H. JIRKA
Keyword(s):  
Grid Turbulence ◽  
Shallow Flows

scholarly journals Shallow Flows Over a Permeable Medium: The Hydrodynamics of Submerged Aquatic Canopies

2008 ◽  
Vol 78 (2) ◽  
pp. 309-326 ◽  
Author(s):  
Marco Ghisalberti ◽  
Heidi Nepf
Keyword(s):  
Shallow Flows

Godunov-type quadtree model of species dispersion in shallow flows

Shallow Flows ◽  
2004 ◽  
pp. 439-448
Author(s):  
A Borthwick ◽  
P Taylor ◽  
J Huang ◽  
Q Liang
Keyword(s):  
Shallow Flows

scholarly journals Impacts of Stochastic Mixing in Idealized Convection-Permitting Simulations of Squall Lines

2020 ◽  
Vol 148 (12) ◽  
pp. 4971-4994
Author(s):  
McKenna W. Stanford ◽  
Hugh Morrison ◽  
Adam Varble
Keyword(s):  
Squall Line ◽  
Weather Research And Forecasting ◽  
Cold Pool ◽  
Multiplicative Factor ◽  
Mesoscale Structure ◽  
Squall Lines ◽  
Mixing Coefficients ◽  
Horizontal Mixing ◽  
Upper Level ◽  
Inflow Jet

AbstractThis study investigates impacts of altering subgrid-scale mixing in “convection-permitting” kilometer-scale horizontal-grid-spacing (Δh) simulations by applying either constant or stochastic multiplicative factors to the horizontal mixing coefficients within the Weather Research and Forecasting Model. In quasi-idealized 1-km Δh simulations of two observationally based squall-line cases, constant enhanced mixing produces larger updraft cores that are more dilute at upper levels, weakens the cold pool, rear-inflow jet, and front-to-rear flow of the squall line, and degrades the model’s effective resolution. Reducing mixing by a constant multiplicative factor has the opposite effect on all metrics. Completely turning off parameterized horizontal mixing produces bulk updraft statistics and squall-line mesoscale structure closest to an LES “benchmark” among all 1-km simulations, although the updraft cores are too undilute. The stochastic mixing scheme, which applies a multiplicative factor to the mixing coefficients that varies stochastically in time and space, is employed at 0.5-, 1-, and 2-km Δh. It generally reduces midlevel vertical velocities and enhances upper-level vertical velocities compared to simulations using the standard mixing scheme, with more substantial impacts at 1- and 2-km Δh compared to 0.5-km Δh. The stochastic scheme also increases updraft dilution to better agree with the LES for one case, but has less impact on the other case. Stochastic mixing acts to weaken the cold pool but without a significant impact on squall-line propagation. It also does not affect the model’s overall effective resolution unlike applying constant multiplicative factors to the mixing coefficients.

Raindrop Size and Flow Depth Control Sediment Sorting in Shallow Flows on Steep Slopes

2018 ◽  
Vol 54 (12) ◽  
pp. 9978-9995 ◽  
Author(s):  
L. Wang ◽  
N. F. Fang ◽  
Z. J. Yue ◽  
Z. H. Shi ◽  
L. Hua
Keyword(s):  
Flow Depth ◽  
Control Sediment ◽  
Shallow Flows ◽  
Depth Control ◽  
Sediment Sorting ◽  
Raindrop Size ◽  
Steep Slopes

Numerical Simulating Open-Channel Flows with Regular and Irregular Cross-Section Shapes Based on Finite Volume Godunov-Type Scheme

2020 ◽  
pp. 2050047
Author(s):  
Xiaokang Xin ◽  
Fengpeng Bai ◽  
Kefeng Li
Keyword(s):  
Finite Volume ◽  
Cross Section ◽  
Cross Sections ◽  
Open Channel ◽  
Arbitrary Cross Section ◽  
Second Order ◽  
Cross Sectional ◽  
Shallow Flows ◽  
Natural Streams ◽  
Saint Venant Equations

A numerical model based on the Saint-Venant equations (one-dimensional shallow water equations) is proposed to simulate shallow flows in an open channel with regular and irregular cross-section shapes. The Saint-Venant equations are solved by the finite-volume method based on Godunov-type framework with a modified Harten, Lax, and van Leer (HLL) approximate Riemann solver. Cross-sectional area is replaced by water surface level as one of primitive variables. Two numerical integral algorithms, compound trapezoidal and Gauss–Legendre integrations, are used to compute the hydrostatic pressure thrust term for natural streams with arbitrary and irregular cross-sections. The Monotonic Upstream-Centered Scheme for Conservation Laws (MUSCL) and second-order Runge–Kutta methods is adopted to achieve second-order accuracy in space and time, respectively. The performance of the resulting scheme is evaluated by application in rectangular channels, trapezoidal channels, and a natural mountain river. The results are compared with analytical solutions and experimental or measured data. It is demonstrated that the numerical scheme can simulate shallow flows with arbitrary cross-section shapes in practical conditions.

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