Fluid Dynamics Code User Manual
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UCRL-MA-121344 HYDRA ? A Finite Element Computational Fluid Dynamics Code User Manual Mark A. Christon Mechanical Engineering University of California Lawrence Livermore National Laboratory June 1995 DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of Wornia nor any of their employees, makes any warranty, express or implied, or assumes any legal hbility or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents .fiat its use would not infringe privately owned rights. 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DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. HYDRA: j A Finite Element 1 i ‘i Computational Fluid Dynamics Code 5 Mark A. Christon Lawrence Livermore National Laboratory 1I i Livermore, California 94551 USA i t i i June, 1995 i i Ai University of California LamceLiiermore lY National Laboratory Table of Contents Preface .............................................................................................. 1 Chapter 1 ........................................................................................... 3 Introduction ........................................................................................ 3 1.1 History of HYDRA Development ............................................... -3 1.2 HYDRA Capabilities ............................................................... 4 1.2.1 Pre-Processor Interfaces ............................................... 4 1.2.2 Post-Processor Interfaces .............................................. 5 1.2.3 Material Models ......................................................... 7 1.3 Guide to the HYDRA User’s Manual ........................................... -8 Chapter 2 ........................................................................................... 9 Theoretical Overview ............................................................................. 9 2.1 The Navier-Stokes Equations ..................................................... 9 2.2 The Advection-Diffusion Equation ............................................... 11 2.3 Spatial Discretization ............................................................... 11 2.4 Element Technology ............................................................... 12 2.5 Grid Parameters .................................................................... 17 2.6 Explicit Time Integration .......................................................... 20 2.7 The Semi-Implicit Projection ...................................................... 21 2.8 Start-up Procedures ................................................................ 23 2.9 The Pressure Poisson Equation ................................................... 24 2.10 Turbulence Models ............................................................... 28 2.11 Derived Variables ................................................................. 29 2.12 Vectorization. Parallelization. and Performance............................... 29 Chapter 3 ........................................................................................... 33 Running HYDM ................................................................................. 33 3.1 Execution ............................................................................ 33 3.2 Restarts .............................................................................. 34 Chapter 4 ........................................................................................... 35 HYDW Input Data .............................................................................. -35 4.1 HYDRA Control File .............................................................. 35 4.1.1 Mesh Parameters ........................................................ 35 4.1.2 Analysis Parameters ................................................... -37 4.1.3 Momentum Equation-Solver Parameters .......................... -41 4.1.4 Pressure Poisson Equation-Solver Parameters .................... 42 4.1.5 Time History Blocks .................... .............................. 47 ........ ... - 4.1.6 Turbulence Models ..................................................... 48 4.2 HYDRAMeshFile ................................................................. 49 4.2.1 Nodal Coordinates ...................................................... 49 4.2.2 Connectivity-QUPO elements........................................ 49 4.2.3 Velocity Initial Conditions ............................................. 50 4.2.4 Thermal Initial Conditions ............................................ -50 . 4.2.5 Prescribed Turbulence Model Initial Conditions ...................50 4.2.6 Periodic Boundary Conditions ....................................... 51 4.2.7 Prescribed Boundaq Conditions ..................................... 51 4.3 The Advection-Diffusion Equation .............................................. -53 4.3.1 Prescribed Velocity Field .............................................. 53 4.3.2 Temperature Initial Conditions ........................................ 53 4.3.3 Temperature Boundary Conditions ................................... 54 Chapter 5 .......................................................................................... -55 Example Problems ................................................................................ 55 5.1 Entrance Region in a 2-D Duct .................................................... 55 5.2 Lid Driven Cavity .................................................................. 62 5.3 Vortex Shedding.................................................................... 68 5.4. Backward Facing Step ............................................................ 73 5.5 Circular Duct Entrance Region .................................................... 78 5.6 Vortex Shedding.................................................................... 83 5.7 Post & Plate ......................................................................... 88 Bibliography ....................................................................................... 95 1 Preface HYDRA is a finite element code which has been developed specifically to attack the class of transient, incompressible, viscous, computational fluid dynamics problems which are predominant in the world which surrounds us. The goal for HYDRA has been to achieve high performance across a spectrum of supercomputer architectures without sacrificing any of the aspects of the finite element method which make it so flexible and permit application to a broad class of problems. As supercomputer algorithms evolve, the continuing development of HYDRA will strive to achieve optimal mappings of the most advanced flow solution algorithms onto supercomputer architectures. The development of HYDRA has drawn, in part, upon over ten years of research in computational fluid dynamics by Phil Gresho, Stevens Chan and their colleagues. Certainly, the work by Helmut Daniels with the PASTIS code (a research version of the Projection-11 algorithm) has proven valuable, if in only identifying the obvious memory and performance issues to consider. HYDRA has glso drawn upon the many years of finite element expertise constituted by DYNA3D’ and NIKE3D2 Certain key architectural ideas from both DYNA3D and NIKE3D have been adopted and further improved to fit the advanced dynamic memory management and data structures implemented in HYDRA. HYDU, in its implementation, reflects, to a certain degree, my training and experience with supercomputers beginning with the CYBER 205 and progressing through the CRAY UNICOS “friendly user” period at both the National Center for. Supercomputing Applications’and at the Pittsburgh Supercomputer Center to the ongoing parallel efforts with the Meiko CS-2 at LLNL. The philosophy for HYDRA is to focus on mapping flow algorithms to computer architectures to try and achieve a high level of performance, rather than just performing a port-a philosophy I adopted from Dan Pryor and Pat Burns during my days as a graduate student at Colorado State University. I wish to thank Jerry Goudreau and Phil Gresho for their help, encouragement and periodic moral support during the initial development of HYDRA. I would also like to express my appreciation for the help which Brad Maker provided through his discussions with me regarding the Gibbs-Poole-Stockmeyer bandwidth minimization algorithm,