Encyclopaedia Index

GENIE (a GENeric Interfacing Environment) for PHOENICS

Contents

  1. General description
  2. PEN
  3. NEP

1. General description

GENIE is a "shell", supplied as part of PHOENICS, which facilitates the linking of PHOENICS (including multiblock) with finite-element-based grid-generators and viewers.

GENIE's subroutines perform the common (ie, generic) tasks which must be performed by an interface to any FE code. In this way the creation of each interface is greatly simplified, since it is necessary to provide only "mini-translators" to handle code- specific tasks.

GENIE consists of two parts:

  1. a set of subroutines used for the conversion of grids and patches from external programs into SATELLITE Q1 and XYZ files, called the PEN (PHOENICS Element Neutral file) system; and
  2. a set of subroutines for the conversion of PHOENICS results, called the NEP ("PEN" spelt backwards) system.

A complete PHOENICS system using GENIE with external codes would be: 


 Grid   -----> Input ------> GENIE's ----> Q1 and ---> --
 Generator     Translator    PEN system    Grid files    |
                                                     |
                                                     |
  ------ <-------------- PHOENICS <----------------- <---
 |
 |
  --> PHI, PATGEO ---> GENIE's  ----> Results ---> Results
      and XYZ          NEP system     Translator   Viewer

The code-specific input and output translators are available from three sources:

  1. As optional add-ons to PHOENICS, CHAM supplies input translators for Patran, Algor and ICEM (boundary conditions can also be input within the ICEM environment). For visualisation of PHOENICS results, CHAM currently supplies translators for TecPlot and Patran.

  2. A number of third-party code vendors offer input and output translators which link directly into the GENIE system. These include FemSys Ltd and Numeca Intl SA who provide translators for their complete grid-generation and results-viewing systems FemGen/FemView and IGG/CFView.

  3. The decision to incorporate GENIE into the standard PHOENICS package means that this environment is now available to all PHOENICS users to facilitate the linking of ANY commercial or in-house finite element based code to PHOENICS. On-line documentation is provided within PHOENICS to assist in the creation of the necessary translators. CHAM will also undertake to write special translators on a contract basis.

Both the PEN and NEP systems can be accessed as FORTRAN libraries or via their associated neutral files. The function of the system is the same whether the data are passed via files or arrays.

2. PEN

The functions performed by the PEN system are:-

  1. Element-based grids are converted into IJK-structured blocks.

  2. PHOENICS links are found for blocks created from element-based grids or read in from IJK-structured grid generators.

  3. The blocks that are linked together are re-oriented so they conform to the PHOENICS blocks stacking rules.

  4. PATCHES for grids from IJK-structured grid generators are reoriented if necessary.

  5. Lists of nodes from element-based grid generators are converted into PHOENICS patches.

  6. Non-geometric commands in an existing Q1 file can be appended to the Q1 files created by the PEN system.

3. NEP

The functions performed by the NEP system are:-

  1. The grids for the constituent blocks of the model are extracted from the single-whole-model grid output by EARTH.

  2. If required, the grid is converted into an element-based grid.

  3. The results for the constituent blocks of the model are extracted from the single-whole-model results blocks output by EARTH.

  4. The PRPS and VPOR flags can be used to reduce the list of cell- centre results to only those that are valid excluding those for blocked cells where appropriate.

  5. Nodally-averaged results can be calculated for scalar results. If a node lies on a material boundary, multiple results for a node will be given. If there is no valid result for a node, no result is given. Nodal averaging is performed across block boundaries if required.

  6. The valid velocities are located and averaged according to their type. Collocated velocities are treated as scalars, all other velocities are treated as cell face values. For polar grids a Cartesian velocity set is created.

(Acknowledgement: GENIE was written by Caroline Young Consulting under subcontract to CHAM)