CIP and Parallel Computing Based Numerical Solutions of 3-D Slamming Problems

2015 ◽  
Author(s):  
Peng Wen ◽  
Wei Qiu
Keyword(s):  
Parallel Computing ◽  
Message Passing ◽  
Message Passing Interface ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Simulation Method ◽  
Water Entry ◽  
Computational Domain ◽  
Cip Method ◽  
Constrained Interpolation

This paper presents the further development of numerical simulation method to solve 3-D highly non-linear slamming problems using parallel computing algorithms. The water entry problems are treated as multi-phase problems (solid, water and air) and governed by the Navier-Stokes (N-S) equations. They are solved by the three-dimensional constrained interpolation profile (CIP) method. The interfaces between different phases are captured using density functions. In the computation, the 3-D CIP method is employed for the advection phase of the N-S equations and a pressure-based algorithm is applied for the non-advection phase. The bi-conjugate gradient stabilized method (BiCGSTAB) is utilized to solve the linear equation systems. A Message Passing Interface (MPI) parallel computing scheme was implemented in the computations. For the parallel computations, the three-dimensional Cartesian decomposition of the computational domain was used. The speed-up performance of various decomposition schemes were studied. Validation studies were carried out for the water entry of a 3-D wedge and a 3-D ship section with prescribed velocities. The computed slamming force, pressure distribution and free-surface elevations are compared with experimental results and numerical results by other methods.

Numerical Solution of 2-D Water Entry Problems Based on a CIP Method and a Parallel Computing Algorithm

2015 ◽  
Author(s):  
Peng Wen ◽  
Wei Qiu
Keyword(s):  
Parallel Computing ◽  
Message Passing ◽  
Message Passing Interface ◽  
Water Entry ◽  
Navier Stokes ◽  
Cip Method ◽  
Constrained Interpolation ◽  
Decomposition Scheme ◽  
Computing Algorithm ◽  
Speed Up

A constrained interpolation profile (CIP) method has been developed to solve 2-D water entry problems. This paper presents the further development of the numerical method using staggered grids and a parallel computing algorithm. In this work, the multi-phase slamming problems, governed by the Navier-Stokes (N-S) equations, are solved by a CIP-based finite difference method. The interfaces between different phases (solid, water and air) are captured using density functions. A parallel computing algorithm based on the Message Passing Interface (MPI) method and the domain decomposition scheme was implemented to speed up the computations. The effect of decomposition scheme on the solution and the speed-up were studied. Validation studies were carried out for the water entry of various 2-D wedges and a ship section. The predicted slamming force, pressure distribution and free surface elevation are compared with experimental results and other numerical results.

A Simulation of Domain Decomposition Method for Smoothed Particle Hydrodynamics

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Taehyo Park ◽  
Shengjie Li ◽  
Mina Lee ◽  
Moonho Tak
Keyword(s):  
Parallel Computing ◽  
Smoothed Particle Hydrodynamics ◽  
Message Passing ◽  
Message Passing Interface ◽  
Domain Decomposition Method ◽  
Computational Domain ◽  
Sph Method ◽  
Multiple Data ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Nowadays, the numerical method has become a very important approach for solving complex problems in engineering and science. Some grid-based methods such as the finite difference method (FDM) and finite element method (FEM) have already been widely applied to various areas; however, they still suffer from inherent difficulties which limit their applications to many problems. Therefore, a strong interest is focused on the meshfree methods such as smoothed particle hydrodynamics (SPH) to simulate fluid flow recently due to the advantages in dealing with some complicated problems. In the SPH method, a great number of particles will be used because the whole domain is represented by a set of arbitrarily distributed particles. To improve the numerical efficiency, parallelization using message-passing interface (MPI) is applied to the problems with the large computational domain. In parallel computing, the whole domain is decomposed by the parallel method for continuity of subdomain boundary under the single instruction multiple data (SIMD) and also based on the procedure of the SPH computations. In this work, a new scheme of parallel computing is employed into the SPH method to analyze SPH particle fluid. In this scheme, the whole domain is decomposed into subdomains under the SIMD process and it composes the boundary conditions to the interface particles which will improve the detection of neighbor particles near the boundary. With the method of parallel computing, the SPH method is to be more flexible and perform better.

scholarly journals Parallelizing a serial code: open–source module, EZ Parallel 1.0, and geophysics examples

2020 ◽  
Author(s):  
Jason Louis Turner ◽  
Samuel N. Stechmann
Keyword(s):  
Parallel Computing ◽  
Finite Difference ◽  
Message Passing ◽  
Message Passing Interface ◽  
Three Dimensional ◽  
Computer Architectures ◽  
Strong Scaling ◽  
Pseudo Spectral ◽  
Fortran Programming Language ◽  
Single Processor

Abstract. Parallel computing can offer substantial speedup of numerical simulations in comparison to serial computing, as parallel computing uses many processors simultaneously rather than a single processor. However, it typically also requires substantial time and effort to convert a serial code into a parallel code. Here, a new module is developed to reduce the time and effort required to parallelize a serial code. The tested version of the module is written in the Fortran programming language,while the framework could also be extended to other languages (C++, Python, Julia, etc.). The Message Passing Interface is used to allow for either shared-memory or distributed-memory computer architectures. The software is designed for solving partial differential equations on a rectangular two-dimensional or three-dimensional domain, using finite difference, finite volume, pseudo-spectral, or other similar numerical methods. Examples are provided for two idealized models of atmospheric and oceanic fluid dynamics: the two-level quasi-geostrophic equations, and the stochastic heat equation as a model for turbulent advection–diffusion of either water vapor and clouds or sea surface height variability. In tests of the parallelized code, the strong scaling efficiency for the finite difference code is seen to be roughly 80 % to 90 %, which is achieved by adding roughly only 10 new lines to the serial code. Therefore, EZ Parallel provides great benefits with minimal additional effort.

Simulation-Based Scheduling of Waterway Projects Using a Parallel Genetic Algorithm

2015 ◽  
pp. 334-347 ◽  
Author(s):  
Ning Yang ◽  
Shiaaulir Wang ◽  
Paul Schonfeld
Keyword(s):  
Genetic Algorithm ◽  
Parallel Computing ◽  
Message Passing ◽  
Message Passing Interface ◽  
Computation Time ◽  
Parallel Genetic Algorithm ◽  
Simulation Based ◽  
Multiple Processors ◽  
Simulation Based Optimization ◽  
Speed Up

A Parallel Genetic Algorithm (PGA) is used for a simulation-based optimization of waterway project schedules. This PGA is designed to distribute a Genetic Algorithm application over multiple processors in order to speed up the solution search procedure for a very large combinational problem. The proposed PGA is based on a global parallel model, which is also called a master-slave model. A Message-Passing Interface (MPI) is used in developing the parallel computing program. A case study is presented, whose results show how the adaption of a simulation-based optimization algorithm to parallel computing can greatly reduce computation time. Additional techniques which are found to further improve the PGA performance include: (1) choosing an appropriate task distribution method, (2) distributing simulation replications instead of different solutions, (3) avoiding the simulation of duplicate solutions, (4) avoiding running multiple simulations simultaneously in shared-memory processors, and (5) avoiding using multiple processors which belong to different clusters (physical sub-networks).

Interpretive MPI for Parallel Computing

2008 ◽  
Author(s):  
Yu-Cheng Chou ◽  
Harry H. Cheng
Keyword(s):  
Parallel Computing ◽  
Programming Languages ◽  
Message Passing ◽  
Large Scale ◽  
Message Passing Interface ◽  
Rapid Development ◽  
Web Based ◽  
Heterogeneous Platforms ◽  
C Programs ◽  
Computation Speedup

Message Passing Interface (MPI) is a standardized library specification designed for message-passing parallel programming on large-scale distributed systems. A number of MPI libraries have been implemented to allow users to develop portable programs using the scientific programming languages, Fortran, C and C++. Ch is an embeddable C/C++ interpreter that provides an interpretive environment for C/C++ based scripts and programs. Combining Ch with any MPI C/C++ library provides the functionality for rapid development of MPI C/C++ programs without compilation. In this article, the method of interfacing Ch scripts with MPI C implementations is introduced by using the MPICH2 C library as an example. The MPICH2-based Ch MPI package provides users with the ability to interpretively run MPI C program based on the MPICH2 C library. Running MPI programs through the MPICH2-based Ch MPI package across heterogeneous platforms consisting of Linux and Windows machines is illustrated. Comparisons for the bandwidth, latency, and parallel computation speedup between C MPI, Ch MPI, and MPI for Python in an Ethernet-based environment comprising identical Linux machines are presented. A Web-based example is given to demonstrate the use of Ch and MPICH2 in C based CGI scripting to facilitate the development of Web-based applications for parallel computing.

Parallel Computation of Unsteady Incompressible Viscous Flows Using an Unstructured Multigrid Method

2002 ◽  
Author(s):  
Yong Zhao ◽  
Chin Hoe Tai
Keyword(s):  
Unsteady Flow ◽  
Message Passing ◽  
Message Passing Interface ◽  
Multigrid Method ◽  
Numerical Solutions ◽  
Viscous Flows ◽  
Finite Volume Scheme ◽  
Decomposition Approach ◽  
Incompressible Viscous Flows ◽  
Multigrid Solvers

The development and validation of a parallel unstructured non-nested multigrid method for simulation of unsteady incompressible viscous flow is presented. The Navier-Stokes solver is based on the artificial compressibility method (ACM) [10] and a higher-order characteristics-based finite-volume scheme [8] on unstructured multigrids. Unsteady flow is calculated with an implicit dual time stepping scheme. The parallelization of the solver is achieved by a multigrid domain decomposition approach (MG-DD), using the Single Program Multiple Data (SPMD) programming paradigm and Message-Passing Interface (MPI) for communication of data. The parallel codes using single grids and multigrids are used to simulate steady and unsteady incompressible viscous flows over a circular cylinder for validation and performance evaluation purposes. Speedups and parallel efficiencies obtained by both the parallel single-grid and multigrid solvers are reasonably good for both test cases, using up to 32 processors on the SGI Origin 2000. A maximum speedup of 12 could be achieved on 16 processors for the unsteady flow. The parallel results obtained agree well with those of serial solvers and with numerical solutions obtained by other researchers, as well as experimental measurements.

Study on the Numerical Simulation of Explosion and Impact Processes Using PC Cluster System

2012 ◽  
Vol 433-440 ◽  
pp. 2892-2898
Author(s):  
Guang Lei Fei ◽  
Jian Guo Ning ◽  
Tian Bao Ma
Keyword(s):  
Numerical Simulation ◽  
Operating System ◽  
Parallel Computing ◽  
Message Passing ◽  
Message Passing Interface ◽  
Parallel Program ◽  
Pc Cluster ◽  
Computing Platform ◽  
Impact Processes ◽  
Platform System

Parallel computing has been applied in many fields, and the parallel computing platform system, PC cluster based on MPI (Message Passing Interface) library under Linux operating system is a cost-effectiveness approach to parallel compute. In this paper, the key algorithm of parallel program of explosion and impact is presented. The techniques of solving data dependence and realizing communication between subdomain are proposed. From the test of program, the portability of MMIC-3D parallel program is satisfied, and compared with the single computer, PC cluster can improve the calculation speed and enlarge the scale greatly.

Evaluation of a Parallel Agglomeration Multigrid Finite-Volume Algorithm, Named Galatea-I, for the Simulation of Incompressible Flows on 3D Hybrid Unstructured Grids

2014 ◽  
Author(s):  
Sotirios S. Sarakinos ◽  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Finite Volume ◽  
Message Passing ◽  
Data Exchange ◽  
Message Passing Interface ◽  
Incompressible Flows ◽  
Navier Stokes ◽  
Finite Volume Scheme ◽  
Computational Domain ◽  
Naca0012 Airfoil ◽  
Computational Performance

In this study an academic Computational Fluid Dynamics (CFD) code, named Galatea-I, is described, which employs the Reynolds Averaged Navier–Stokes (RANS) equations along with the artificial compressibility method and the SST (Shear Stress Transport) turbulence model for the prediction of incompressible viscous flows. For the representation of the computational domain unstructured hybrid grids are utilized, composed of tetrahedral, prismatic and pyramidical elements, while for its discretization a node-centered finite-volume scheme is implemented. Galatea-I is enhanced with a parallelization method, which employs spatial domain decomposition, while the data exchange between processors/processes is performed with the use of the Message Passing Interface (MPI) protocol. In addition, a parallel agglomeration multigrid methodology has been incorporated to improve further its computational performance. The proposed code is validated against steady-state flow benchmark test cases, concerning laminar flow over a cubic cavity and a cylindrical surface, as well as turbulent flow over a rectangular wing with a NACA0012 airfoil. The obtained results, compared with these of corresponding reference solvers, reveal Galatea-I’s potential for simulation of inviscid, viscous laminar and turbulent incompressible flows.

Numerical Solution of 3-D Water Entry Problems With a Constrained Interpolation Profile Method

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Qingyong Yang ◽  
Wei Qiu
Keyword(s):  
Numerical Solutions ◽  
Stokes Equations ◽  
Type Equation ◽  
Water Entry ◽  
Navier Stokes ◽  
Time Step ◽  
Constrained Interpolation ◽  
Navier Stokes Equations ◽  
Highly Nonlinear ◽  
Calm Water

This paper presents the numerical solutions of slamming problems for 3D bodies entering calm water with vertical and oblique velocities. The highly nonlinear water entry problems are governed by the Navier-Stokes equations and were solved by a constrained interpolation profile (CIP)-based finite difference method on a fixed Cartesian grid. In the computation, the 3D CIP method was employed for the advection calculations and a pressure-based algorithm was applied for the nonadvection calculations. The solid body and the free surface interfaces were captured by density functions. For the pressure computation, a Poisson-type equation was solved at each time step by using the conjugate gradient iterative method. Validation studies were carried out for a 3D wedge, a cusped body vertically entering calm water, and the oblique entry of a sphere into calm water. The predicted hydrodynamic forces on the wedge, the cusped body, and the sphere were compared with experimental data.

scholarly journals Efficient Message Passing Interface (MPI) for Parallel Computing on Clusters of Workstations

1997 ◽  
Vol 40 (1) ◽  
pp. 19-34 ◽  
Author(s):  
Jehoshua Bruck ◽  
Danny Dolev ◽  
Ching-Tien Ho ◽  
Marcel-Cătălin Roşu ◽  
Ray Strong
Keyword(s):  
Parallel Computing ◽  
Message Passing ◽  
Message Passing Interface
Sign in / Sign up

Export Citation Format

Share Document