scholarly journals Finite volume simulation of unsteady water pipe flow

2014 ◽  
Vol 7 (2) ◽  
pp. 83-92 ◽  
Author(s):  
J. Fernández-Pato ◽  
P. García-Navarro
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Finite Volume ◽  
Water Pressure ◽  
Laboratory Data ◽  
Network Models ◽  
Finite Volume Methods ◽  
Analytic Solutions ◽  
Surface Flow ◽  
Pipe Networks

Abstract. The most commonly used hydraulic network models used in the drinking water community exclusively consider fully filled pipes. However, water flow numerical simulation in urban pipe systems may require to model transitions between surface flow and pressurized flow in steady and transient situations. The governing equations for both flow types are different and this must be taken into account in order to get a complete numerical model for solving dynamically transients. In this work, a numerical simulation tool is developed, capable of simulating pipe networks mainly unpressurized, with isolated points of pressurization. For this purpose, the mathematical model is reformulated by means of the Preissmann slot method. This technique provides a reasonable estimation of the water pressure in cases of pressurization. The numerical model is based on the first order Roe's scheme, in the frame of finite volume methods. The novelty of the method is that it is adapted to abrupt transient situations, with subcritical and supercritical flows. The validation has been done by means of several cases with analytic solutions or empirical laboratory data. It has also been applied to some more complex and realistic cases, like junctions or pipe networks.

scholarly journals A pipe network simulation model with dynamic transition between free surface and pressurized flow

2014 ◽  
Vol 7 (1) ◽  
pp. 27-57
Author(s):  
J. Fernández-Pato ◽  
P. García-Navarro
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Simulation Model ◽  
Water Pressure ◽  
Laboratory Data ◽  
Finite Volume Methods ◽  
Analytic Solutions ◽  
Pipe Networks ◽  
Network Simulation Model ◽  
Supercritical Flows

Abstract. Water flow numerical simulation in urban pipe systems is one of the topics that shows the need for surface flows and pressurized flows in steady and transient situations. The governing equations for both flow types are different and this must be taken into account in order to get a complete numerical model for solving transients. A numerical simulation model is developed in this work, capable of solving pipe networks mainly unpressurized, with isolated peaks of pressurization. For this purpose, a reformulation of the mathematical model through the Preissmann slot method is proposed. By means of this technique, a reasonable estimation of the water pressure is calculated in cases of pressurization. The numerical model is based on the first order Roe's scheme, in the frame of finite volume methods. It is adapted to abrupt transient situations, with subcritial and supercritical flows. The validation has been done by means of several cases with analytic solutions or empirical laboratory data. It has also been applied to some more complex and realistic cases, like junctions or pipe networks.

NUMERICAL SIMULATION OF FREE SURFACE FLOW USING A THREE-DIMENSIONAL NUMERICAL MODEL

2011 ◽  
pp. 1361-1367
Author(s):  
J. W. LEE ◽  
K.-H. SEO ◽  
Y.-S. CHO
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Numerical Model ◽  
Three Dimensional ◽  
Free Surface Flow ◽  
Surface Flow

Finite volume methods for numerical simulation of the discharge motion described by different physical models

2019 ◽  
Vol 45 (4) ◽  
pp. 2163-2189
Author(s):  
J. Fořt ◽  
J. Karel ◽  
D. Trdlička ◽  
F. Benkhaldoun ◽  
I. Kissami ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Finite Volume ◽  
Finite Volume Methods ◽  
Physical Models

Numerical Simulation of Indirectly Heated Hot Water Heater

2014 ◽  
Vol 875-877 ◽  
pp. 1693-1697 ◽  
Author(s):  
Richard Lenhard ◽  
Katarína Kaduchová ◽  
Jozef Jandačka
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Finite Volume ◽  
Computational Methods ◽  
Finite Volume Methods ◽  
Hot Water ◽  
Geometrical Parameters ◽  
Water Heater ◽  
Cfd Simulations ◽  
Cfd Method

This paper describes a mathematical model of heating hot water for indirectly heated hot water heater. Using the established mathematical model was carried out simulation of the device to change its geometrical parameters. Based on the results of simulations was carried out optimization of indirectly heated hot water heater for hot water. Subsequently been made CFD simulations of the device, and those were compared with a mathematical model to verify the accuracy of the proposed mathematical model of heating hot water for indirectly heated hot water heater. Computational methods based on finite volume methods (CFD method) have proved very useful in optimizing indirectly heated hot water heater.

scholarly journals A Forward Time Stepping Heat Conduction Model for Spot Melt Additive Manufacturing

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
B. Stump ◽  
A. Plotkowski
Keyword(s):  
Finite Element ◽  
Finite Volume ◽  
Analytic Solution ◽  
Dimensional Space ◽  
Mathematical Formulation ◽  
Finite Volume Methods ◽  
Analytic Solutions ◽  
Conduction Model ◽  
Time Stepping ◽  
Speed And Accuracy

Abstract Solidification dynamics are crucial for determining microstructure development in additively manufactured parts. Multiphysics models based on finite element or finite volume methods may help gain insight for complicated phenomena such as fluid flow, keyholing, and porosity but are too computationally expensive to use for simulating actual builds. Recent analytic and semi-analytic solutions for moving heat sources in a semi-infinite three-dimensional space provide a way to accurately estimate the solidification conditions for entire builds. The downside to these methods is that, unlike finite element or finite volume methods, they cannot use the temperature distribution of the previous timesteps to march the solution forward in time. This paper provides the mathematical formulation and implementation of a forward time stepping (FTS) approach to an existing semi-analytic solution. The speed and accuracy of the two methods are then compared for various scan patterns. The result is that, for spot melts, the forward time-stepping model provides improvements in both speed and accuracy. This is especially true for longer simulations, where the simulation can be orders of magnitude faster. The longest simulation analyzed in this paper was roughly 30× faster when using the forward time-stepping model versus the straightforward implementation of the semi-analytic solution.

scholarly journals Development of a numerical simulation model for suction rate using CADMAS-SURF

2018 ◽  
Vol 192 ◽  
pp. 02063
Author(s):  
Kornvisith Silarom ◽  
Yoshimichi Yamamoto ◽  
Syota Yoshizawa ◽  
Nunthawath Charusrojthanadech
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Simulation Model ◽  
Flow Velocity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Wave Pressure ◽  
Elapsed Time ◽  
Shallow Area ◽  
Suction Rate

There are many cases where a coastal dike or a seawall constructed on a very shallow area was broken by a wave of a smaller height than the designed height. In many of these cases, the reason of the destruction was the suction phenomena. This phenomenon happens when waves reaches the front of the dike or the seawall, the wave pressure scours the front soil of the structure until it reaches the lowest edge of the structure followed by sucking of backfilling material of the structure. In this research, the authors proposed the numerical model which can calculate the suction rate with elapsed time by applying the pore water pressure and the flow velocity inside a dike or a seawall using “CADMAS-SURF”. The authors proposed three coefficients for improving the calculated pressure from CADMAS-SURF. The reliability of the model was confirmed by reproducing the suction phenomena in Hirono Coast of Japan.

scholarly journals Coupled Finite Volume Methods and Extended Finite Element Methods for the Dynamic Crack Propagation Modelling with the Pressurized Crack Surfaces

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Shouyan Jiang ◽  
Chengbin Du
Keyword(s):  
Finite Element ◽  
Pressure Distribution ◽  
Finite Volume ◽  
Finite Element Methods ◽  
Water Pressure ◽  
Finite Volume Methods ◽  
Implicit Time ◽  
Dynamic Crack Propagation ◽  
Dynamic Crack ◽  
Extended Finite Element

We model the fluid flow within the crack as one-dimensional flow and assume that the flow is laminar; the fluid is incompressible and accounts for the time-dependent rate of crack opening. Here, we discretise the flow equation by finite volume methods. The extended finite element methods are used for solving solid medium with crack under dynamic loads. Having constructed the approximation of dynamic extended finite element methods, the derivation of governing equation for dynamic extended finite element methods is presented. The implicit time algorithm is elaborated for the time descritisation of dominant equation. In addition, the interaction integral method is given for evaluating stress intensity factors. Then, the coupling model for modelling hydraulic fracture can be established by the extended finite element methods and the finite volume methods. We compare our present numerical results with our experimental results for verifying the proposed model. Finally, we investigate the water pressure distribution along crack surface and the effect of water pressure distribution on the fracture property.

Sign in / Sign up

Export Citation Format

Share Document