scholarly journals Imposing accurate wall boundary conditions in corrective‐matrix‐based moving particle semi‐implicit method for free surface flow

2020 ◽  
Vol 93 (1) ◽  
pp. 148-175 ◽  
Author(s):  
Guangtao Duan ◽  
Takuya Matsunaga ◽  
Akifumi Yamaji ◽  
Seiichi Koshizuka ◽  
Mikio Sakai
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Implicit Method ◽  
Wall Boundary ◽  
Wall Boundary Conditions ◽  
Moving Particle

scholarly journals Meshless particle modelling of free surface flow over spillways

2015 ◽  
Vol 18 (2) ◽  
pp. 354-370 ◽  
Author(s):  
Ehsan Jafari-Nodoushan ◽  
Khosrow Hosseini ◽  
Ahmad Shakibaeinia ◽  
Seyed-Farhad Mousavi
Keyword(s):  
Free Surface ◽  
Surface Profile ◽  
Particle Method ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Weakly Compressible ◽  
Wall Boundary Conditions ◽  
Free Surface Profile ◽  
Moving Particle ◽  
Lagrangian Particle Method

A meshless Lagrangian (particle) method based on the weakly compressible moving particle semi-implicit formulation (WC-MPS) is developed and analysed for simulation of flow over spillways. To improve the accuracy of the model for pressure and velocity calculation, some modifications are proposed and evaluated for the inflow and wall boundary conditions implementation methods. The final model is applied for simulation of flow over the 45° and 60° ogee spillways (with different inflow rates) and also shallow flow over a spillway-like curved bed channel. To evaluate the model, the numerical results of free surface profile and velocity and pressure field are compared with the available experimental measurements. Comparisons show the results’ accuracy of the developed model and proposed improvements. The results of this study will not only provide a reliable numerical tool for modelling of flow over spillways, but also provide an insight for better understating flow pattern over these hydraulic structures.

scholarly journals Numerical analysis of the nonlinear free surface flow around an advancing ship using moving particle semi-implicit method

AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035106
Author(s):  
CholJun Pak ◽  
PokNam Han ◽  
KwangChol Ri ◽  
YongKwang Ri ◽  
InChol Hwang
Keyword(s):  
Free Surface ◽  
Numerical Analysis ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Implicit Method ◽  
Moving Particle ◽  
Nonlinear Free Surface

A Stable Semi-Implicit Method for Free Surface Flows

2005 ◽  
Vol 73 (6) ◽  
pp. 940-947 ◽  
Author(s):  
Cassio M. Oishi ◽  
José A. Cuminato ◽  
Valdemir G. Ferreira ◽  
Murilo F. Tomé ◽  
Antonio Castelo ◽  
...  
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Stokes Equations ◽  
Free Surface Flow ◽  
Free Surface Flows ◽  
Surface Flow ◽  
Navier Stokes ◽  
Variable Order ◽  
Implicit Methods ◽  
Time Lagged

The present work is concerned with a semi-implicit modification of the GENSMAC method for solving the two-dimensional time-dependent incompressible Navier-Stokes equations in primitive variables formulation with a free surface. A projection method is employed to uncouple the velocity components and pressure, thus allowing the solution of each variable separately (a segregated approach). The viscous terms are treated by the implicit backward method in time and a centered second order method in space, and the nonlinear convection terms are explicitly approximated by the high order upwind variable-order nonoscillatory scheme method in space. The boundary conditions at the free surface couple the otherwise segregated velocity and pressure fields. The present work proposes a method that allows the segregated solution of free surface flow problems to be computed by semi-implicit schemes that preserve the stability conditions of the related coupled semi-implicit scheme. The numerical method is applied to both the simulation of free surface and to confined flows. The numerical results demonstrate that the present technique eliminates the parabolic stability restriction required by the original explicit GENSMAC method, and also found in segregated semi-implicit methods with time-lagged boundary conditions. For low Reynolds number flows, the method is robust and very efficient when compared to the original GENSMAC method.

scholarly journals A parallelized algorithm to speed up 1D free-surface flow simulations in irrigation canals

2020 ◽  
Vol 22 (6) ◽  
pp. 1620-1639
Author(s):  
Lucas Bessone ◽  
Joan Soler-Guitart ◽  
Pablo Gamazo
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Internal Boundary ◽  
External Boundary ◽  
Irrigation Canals ◽  
Flow Simulations ◽  
Prediction Horizon ◽  
And Performance

Abstract A parallel algorithm for 1D free-surface flow simulations in irrigation canals is shown. The model is based on the Hartree method applied to Saint-Venant equations. Due to the close-to-steady flow nature in irrigation canals, external and internal boundary conditions are linearized to preserve the parallel character. Gate trajectories, off-take withdrawals, and external boundary conditions are modeled as piece-wise functions of time, so there are discontinuities. To achieve a fully parallelized algorithm, an explicit version of the Hartree method is chosen, and external and internal boundary conditions are linearized around operation point. This approach is used to build a computer simulator, written in C-CUDA language. Two tests by ASCE Committee on Canal Automation Algorithms have been used to evaluate accuracy and performance of the algorithm. The Maricopa Stanfield benchmark has been used to prove its accuracy, and the Corning Canal benchmark to evaluate performance in terms of processing time. Surprisingly, solving a 12 hr-long prediction horizon with a cell size of about Δx= 10 m is less than 1 s on a Nvidia K40 card. Results were compared with a serial and a multi-CPU version of the same algorithm. The implementation that showed the best performance on different platforms is the one that uses GPU.

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