The Preissmann box scheme and its modification for transcritical flows

2007 ◽  
Vol 70 (7) ◽  
pp. 791-811 ◽  
Author(s):  
M. A. Freitag ◽  
K. W. Morton
Keyword(s):  
Box Scheme ◽  
Transcritical Flows

Applicability of Preissmann box scheme for calculation of transcritical flow in pipes

2019 ◽  
Vol 19 (5) ◽  
pp. 1429-1437
Author(s):  
Yanmei Wang ◽  
Chengcai Zhang ◽  
Zhansong Li ◽  
Bin Sun ◽  
Haolan Zhou
Keyword(s):  
Numerical Model ◽  
Momentum Equation ◽  
Internal Boundary ◽  
Urban Drainage ◽  
Box Scheme ◽  
Pipe Networks ◽  
Wide Range ◽  
Transcritical Flow ◽  
Transcritical Flows ◽  
Supercritical Flows

Abstract The accurate computer simulation of pipe flow is of great importance in the design of urban drainage. The Preissmann box scheme is usually used to model a wide range of subcritical and supercritical flows. However, care must be taken over the modelling of transcritical flows since, unless the correct internal boundary conditions are imposed, the scheme becomes unstable. In this paper, using the scheme in conjunction with the reduced momentum equation and applying boundary condition structure inherent to subcritical flow to all regimes, is an approach that enables efficient numerical simulation of transcritical flows in pipe networks. The approach includes three steps. First, a unified mathematical model which is based on the Preissmann slot model is derived. Second, the Preissmann box scheme is used to solve the set of equations, by analyzing and discussing the origin of the invalidity of applying the scheme, and a numerical model suitable for transcritical flow is proposed by the method of changing the convection acceleration term. Third, the numerical model is assessed by comparison with analytical, experimental and numerical results. The proposed models verified that this method can make the Preissmann box scheme applicable to the computation of transcritical flow in pipes.

scholarly journals Numerical Simulation of Heat Transfer Flow Subject to MHD of Williamson Nanofluid with Thermal Radiation

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 10
Author(s):  
Muhammad Amer Qureshi
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Single Phase ◽  
Physical Parameters ◽  
Fundamental Symmetry ◽  
Box Scheme ◽  
Mhd Boundary Layer ◽  
Slippery Surface ◽  
Transfer Flow

In this paper, heat transfer and entropy of steady Williamson nanofluid flow based on the fundamental symmetry is studied. The fluid is positioned over a stretched flat surface moving non-uniformly. Nanofluid is analyzed for its flow and thermal transport properties by consigning it to a convectively heated slippery surface. Thermal conductivity is assumed to be varied with temperature impacted by thermal radiation along with axisymmetric magnetohydrodynamics (MHD). Boundary layer approximations lead to partial differential equations, which are transformed into ordinary differential equations in light of a single phase model accounting for Cu-water and TiO2-water nanofluids. The resulting ODEs are solved via a finite difference based Keller box scheme. Various formidable physical parameters affecting fluid movement, difference in temperature, system entropy, skin friction and Nusselt number around the boundary are presented graphically and numerically discussed. It has also been observed that the nanofluid based on Cu-water is identified as a superior thermal conductor rather than TiO2-water based nanofluid.

scholarly journals Numerical Method in Two Dimensional Boundary Layer Theory for Incompressible Viscous Fluid

2013 ◽  
Vol 38 ◽  
pp. 61-73
Author(s):  
MA Haque
Keyword(s):  
Boundary Layer ◽  
Viscous Fluid ◽  
Initial Value Problem ◽  
Shooting Method ◽  
Boundary Layer Equation ◽  
Incompressible Viscous Fluid ◽  
Initial Value ◽  
Box Scheme ◽  
Runge Kutta Method ◽  
Dimensional Boundary

In this paper laminar flow of incompressible viscous fluid has been considered. Here two numerical methods for solving boundary layer equation have been discussed; (i) Keller Box scheme, (ii) Shooting Method. In Shooting Method, the boundary value problem has been converted into an equivalent initial value problem. Finally the Runge-Kutta method is used to solve the initial value problem. DOI: http://dx.doi.org/10.3329/rujs.v38i0.16549 Rajshahi University J. of Sci. 38, 61-73 (2010)

scholarly journals Dissipation Effect On A Free Convection Flow Past A Porous Vertical Plate

1970 ◽  
Vol 6 (1) ◽  
pp. 52-59
Author(s):  
Amena Ferdousi ◽  
MA Alim
Keyword(s):  
Free Convection ◽  
Vertical Plate ◽  
Numerical Study ◽  
Porous Plate ◽  
Convection Flow ◽  
Free Convection Flow ◽  
Box Scheme ◽  
Flow Through ◽  
Implicit Finite Difference ◽  
Boundary Equations

A Numerical study on the effect of dissipation on a steady free convection flow through a porous vertical plate is made. The relevant non-leaner boundary equations are made dimensionless using specific non-dimensional variables. The corresponding non-similar partial differential equations are solved using implicit finite difference method with Keller-Box scheme. The results are then presented graphically and discussed thereafter. Keywords: porous plate; viscous dissipation; natural convection. DOI: http://dx.doi.org/10.3329/diujst.v6i1.9334 DIUJST 2011; 6(1): 52-59

scholarly journals Box-Scheme Based Delivery System of Locally Produced Organic Food: Evaluation of Logistics Performance

2011 ◽  
Vol 04 (03) ◽  
pp. 357-367 ◽  
Author(s):  
T. Bosona ◽  
G. Gebresenbet ◽  
I. Nordmark ◽  
D. Ljungberg
Keyword(s):  
Delivery System ◽  
Organic Food ◽  
Box Scheme
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