chimera grid tools user's manual

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Chimera Grid Tools User's Manual

Version 2.1

March, 2010

William M. Chan, Stuart E. Rogers, Shishir A. Pandya, David L. Kao, Pieter G. Buning,

Robert L. Meakin, David A. Boger, Steven M. Nash

RESTRICTIONS - read this before proceeding

NOTICES AND DISCLAIMERS - read this before proceeding

INSTALLATION

Contents

Introduction

Components of Chimera Grid Tools

Authors Information

Bugs

Search for Keywords

References

Article on Chimera Grid Tools

Sponsors

Software Request ProcedureRelease Notes: 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1

Authors' Change Log

Introduction

Chimera Grid Tools (CGT) is a software package containing a variety of tools for the Chimera overset grid

approach [1] for solving complex configuration problems. Several examples of recent computations that used

Chimera Grid Tools for the creation of the grid systems are shown on Figure 1. The current procedure for

performing overset CFD analysis on such configurations is outlined in Figure 2. A typical starting point is a

description of the surface geometry in CAD format, while typical outputs from the process are force and

moment coefficients, pressure distributions, etc. of the configuration under certain specified freestream

conditions. The complete suite of tools necessary to perform such a process includes CAD tools for geometry

manipulation, and geometry defects elimination, Chimera Grid Tools for grid generation and post-processing

[2,3], PEGASUS [4,5], DCF-Xrays [6], (or other equivalent tool) for domain connectivity, OVERFLOW [7]

for solution computation, and FOMOCO Utilities [8,9,10], or USURP [11] for force and moment

computation. Individual tools used in various parts of the process are illustrated in red in Figure 2.

Figure 1: Recent Applications of Chimera Grid Tools

era Grid Tools User's Manual http://people.nas.nasa.gov/~rogers/cgt/doc/

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Space Shuttle Launch Vehicle and Attached Hardware

(Reynaldo J. Gomez, et. al., NASA Johnson Space Center)

Space Shuttle Launch Vehicle and Debris Trajectory Analyses

(Reynaldo J. Gomez, et. al., NASA Johnson Space Center)

Space Shuttle Flowliner Analysis

(Cetin Kiris, NASA Ames Research Center)

Launch Site Flame Trench Analysis


Subsonic Transport with Propulsion and High Lift Devices

(Stuart E. Rogers., NASA Ames Research Center)

X-38 V-131R Crew Return Vehicle

(James S. Greathouse, NASA Johnson Space Center)


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RLV Baseline Turbopump


V-22 Tiltrotor

(Robert L. Meakin, Army Aeroflightdynamics Directorate)

Comanche

(Robert L. Meakin, Army Aeroflightdynamics Directorate)

Figure 2: Overset CFD Process and Tools


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Tools in CGT can be grouped into the following categories: surface grid generation tools, volume grid

generation tools, grid utilities, configuration automation scripts, utility scripts, and post-processing tools. SeeTable 1 below for a brief description of each tool, the category for which it resides, and access to more

detailed documentation. The package is organized with the following directories:

doc/- documentation files and sample input files for grid tools.

examples/- examples suite for most of the tools.

gui/- files for the OVERGRID graphical user interface.

smart/- files for the OVERSMART solution convergence analysis tool.

include/- header files to be included into source codes.

lib/- FORTRAN and C libraries of common routines.


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scriptbin/- scripts used to help automate the overset grid process.

scriptlib/- Tcl script library of low level procedures.

src/- FORTRAN source codes for the high level batch-mode tools.

The docdirectory contains documentation and sample input files for the various grid tools and scripts, as well

as a log of the changes made for each release of CGT.

The examplesdirectory contains a suite of examples to test the tools, and also includes a self-verification tool

named verifyto check that the tools are running properly.

The guidirectory contains files for a graphical user interface called OVERGRID [12,13] that can be used to

access the various grid tools. For a user facing a new problem, it is much easier to perform grid generation

with the assistance of a graphical tool for the first time. Once the gridding strategy has been identified, scripts

can be constructed to generate grids for similar configurations.

The smartdirectory contains files for the solution monitoring and analysis reporting tool OVERSMART

[14].

The includedirectory contains header files that are included into various source code files through use of the

preprocessor.

The libdirectory contains libraries of FORTRAN and C routines that are common to many of the grid tools.

These routines include computation of stretching functions, computation of grid normals, projections of

grids, grid topology determination and enforcement, and many others.

The scriptbindirectory contains a number of Tcl scripts which can automate the building of an overset grid

system following the process illustrated in Figure 2. These scripts will build input files, execute, and provide

error checking for a number of programs, including: volume grid generation (HYPGEN[15,16] and

LEGRID), volume grid smoothing (SMOGRD), domain connectivity using PEGASUS 5.0 (complete input

file) or PEGSUS 4.1 (partial input file) [5], surface fringe point projection (PROGRD), hybrid surface gridgeneration for force and moment computation [8,9,10], flow solution computation using OVERFLOW [7].

See the scriptsmanual for more details. Such scripts have been used to create complex grid systems for

high-lift configurations [16].

The scriptlibdirectory contains a library of Tcl language script procedures that are called by some of the

scripts in the scriptbindirectory, and are available to the user by using the lappend auto_path scriptlib

command. These procedures are also highly useful when building specific grid generation scripts.

The srcdirectory contains the source code for the high-level batch-mode FORTRAN codes that can be run by

the user.

Below is a figure showing the hierarchy of the various modules in the Chimera Grid Tools package:

Figure 3: CGT Hierarchy


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Components of Chimera Grid Tools

Software modules in Chimera Grid Tools consist of a main graphical interface called OVERGRID, and a

number of independent tools in the form of Fortran programs or Tcl scripts that can be called in batch mode.

A brief description of each tool and access to further information is given in Table 1.

Table 1: GUI and Batch Modules in Chimera Grid Tools

OVERGRID- Graphical user interface for visualization and processing of

geometry and grids, grid generation, domain connectivity and flow solver

input preparation

Legend

Color Category Color Category

- Surface Grid Generation - Volume Grid Generation

- Grid Utility - Configuration Automation Script


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gridinf Computes basic grid information

hypgen Generation of a hyperbolic volume grid from a single surface grid [14,15]

hypin Generation of normal spacing function for volume grids

intchk Interpolation stencil quality check using fringe point coordinates

intgrd Generation of a new surface grid onto a reference grid via interpolation

loadis Computation of sectional force coefs on components

lsectFind intersection curve between one intersector surface grid and multiple

intersectee surface grids

makevolCreates a volume grid via HYPGEN/LEGRID, and runs SMOGRD using

OVERFLOW input file

minterp Interpolation of single/multiple grid and solution files

mixsur Generation of hybrid surface grid for force/moment computation

oversmart Generation of solution convergence plot matrices from OVERFLOW history files

overhist Extraction of residual and flow coefficients data from OVERFLOW history files

overint Integration of force/moment and mass flow rate coefficients

overplot GUI for plotting flow coefficients and sectional Cp cuts on components

pip Mass properties calculator

plothole Creates PLOT3D command file for PEGSUS 4.1 boundaries

PreVol Builds OVERFLOW input files, config.tcl, inputs.tcl from surface grid file

p3dConvertConvert PLOT3D grid and q files and OVERFLOW-2 q files between big and

little endian formats

p3dtransConversion of PLOT3D format for curve grids to/from 2/3-column xyz data

format

progrd Projection of points onto a collection of reference grids

qinfo Report OVERFLOW and PLOT3D solution-file information

recurv Grid-point redistribution

reord Grid-point re-ordering for a single grid-line

RunPeg Runs BuildIngrid, pegsus41, and PROGRD using configuration information

sblock Partial surface domain decomposition and grid generation [18]

ScriptClean Cleans up .srf, .vol, .mvlog, etc. files for an entire configuration


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scriptlib Script library containing many Tcl procedures for grid scripts

seamcr Automatic seam curve extraction and spider web grid generation [19]

seamcrt Surface curves creation on surface triangulations

setzeta Generate normal grid-spacing file zetastr.i for HYPGEN program

shftgrd Shifting/translating grid coordinates of a specified subset

smogrdPerform elliptic smoothing in selected grid subset to spread out region of fine

spacing

smooth Smooth grid by performing second order smoothing

smosurf Perform grid spacing smoothing in one direction for volume grids

splitmx Extraction of arbitrary grid subsets from PLOT3D multiple grid file

splitmq Extraction of arbitrary q subsets from PLOT3D multiple grid q file

srap Perform splining, grid point redistribution and projection on curves/surfaces

str2triConvert PLOT3D multiple structured surface panels to CART3D surface

triangulation

strchk Computation and display of local stretching ratio info for grids

stretch Evaluation and display of 1D stretching functions

srf2cad Project structured surface grid back to native solid CAD part

surgrd Generation of a new surface grid onto a collection of reference grids viahyperbolic/algebraic surface grid generation [20]

Tscan Computation of cross sectional area of a triangulated object versus x, y or z

triged Compilation of a variety of grid editing functions for surface triangulations

triload Generation of line loads from surface triangulation grid and solution file

usurpIntegration of force/moment and mass flow rate coefficients on overset surface

grids using polygon clipping

vpro Interpolate velocity profiles from a grid and solution at specified surface normalsor lines

wingcap Generation of surface grid in tip region of wing

wkcut Generation of surface grid in wake region

xinted Perform various combination functions to grid, XINTOUT and INS3D bc files

xrayed Split and combine multiple Xray files with multiple Xrays in each


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Authors Information

Many people have contributed to the different parts of Chimera Grid Tools. A summary of the tools/scripts

and their application is shown in Table 1. See the documentation for the individual tool to determine

authorship. Questions and suggestions can be directed to the corresponding authors (see Table 2).

Table 2: Authors Contact Information

Name Affiliation E-mail address

William M. Chan # NASA Ames Research Center, TNA Branch [email protected]

Stuart E. Rogers # NASA Ames Research Center, TNA Branch [email protected]

Shishir A. Pandya # NASA Ames Research Center, TNA Branch [email protected]

David L. Kao # NASA Ames Research Center, TNR Branch [email protected]

Pieter G. Buning # NASA Langley Research Center [email protected]

Robert L. Meakin * Army Aeroflightdynamics Directorate -

David A. Boger Penn State University Applied Research Laboratory [email protected]

Steven M. Nash * ELORET, NASA Ames Research Center, INA Branch -

# Contributors to version 2.1

* No longer working on project

Bugs

SBLOCK is in alpha test mode and may contain unexpected bugs.

Search for Keywords

Enter keywords for searching:

References

Steger, J. L., Dougherty, F. C. and Benek, J. A., "A Chimera Grid Scheme," Advances

in Grid Generation, K. N. Ghia and U. Ghia, eds., ASME FED-Vol. 5, June, 1983.

1.

Chan, W. M.,"Advances in Software Tools for Pre-processing and Post-processing of2.


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Overset Grid Computations," in Proceedings of the 9th International Conference on

Numerical Grid Generation in Computational Field Simulations, San Jose, California,

June, 2005.

Chan, W. M., CAD Interface, Strand Grid Technology, and Other New Developments in

Chimera Grid Tools 2.0, Proceedings of the 8th Symposium on Overset Composite Grids

and Solution Technology, Houston, Texas, October, 2006.

24.

Rogers, S. E., Suhs, N. E., Dietz, W. E., "PEGASUS 5: An Automated Preprocessor for

Overset-Grid Computational Fluid Dynamics," AIAA Journal, Vol. 41, No. 6, pp.

1037-1045, 2003.

25.

Suhs, N. E., Dietz, W. E., Rogers, S. E., Nash, S. M. and Onufer, J. T., "PEGASUS

User's Guide," Version 5.1c, NASA Ames Research Center, July, 2000.

26.

Meakin, R. L., "Object X-rays for Cutting Holes in Composite Overset Structured

Grids," AIAA Paper 2001-2537, 2001.

27.

Nichols, R. H., Buning, P. G., "User's Manual for OVERFLOW 2.1," University of

Alabama and NASA Langley Research Center, 2008.

28.

Chan, W. M.,"Enhancements to the Hybrid Mesh Approach to Surface Loads Integration

on Overset Structured Grids," AIAA Paper 2009-3990, June, 2009.

29.

Chan, W. M. and Buning, P. G., "Zipper Grids for Force and Moment Computation onOverset Grids," AIAA Paper 95-1681, in Proceedings of the AIAA 12th Computational

Fluid Dynamics Conference, 1995.

30.

Chan, W. M. and Buning, P. G.,"User's Manual for FOMOCO Utilities - Force and Moment

Computation Tools for Overset Grids," NASA TM~110408, July, 1996.

31.

Boger, D. and Dreyer, J., "Prediction of Hydrodynamic Forces and Moments for

Underwater Vehicles Using Overset Grids," AIAA Paper 2006-1148, 44th AIAA Aerospace

Sciences Meeting and Exhibit, Reno, Nevada, Jan., 2006.

32.

Chan, W. M.,"The OVERGRID Interface for Computational Simulations on Overset Grids,"

AIAA Paper 2002-3188, 32nd AIAA Fluid Dynamics Conference, St. Louis, Missouri, June,

2002.

33.

Chan, W. M.,"Innovative Software Streamlines Overset Grid Generation," NAS News,

Vol. 3, No. 3, May-June, 1998.

34.

Kao, D. L., Chan, W. M.,"OVERSMART - A Solution Monitoring and Reporting Tool for

the OVERFLOW Flow Solver," AIAA Paper 2009-3998, June, 2009.

35.

Chan, W. M. and Steger, J. L., "Enhancements of a Three-Dimensional Hyperbolic Grid

Generation Scheme," Appl. Math. and Comput. 51, 181--205, 1992.

36.

Chan, W. M., Chiu, I.-T., and Buning, P. G., "User's Manual for the HYPGEN

Hyperbolic Grid Generator and the HGUI Graphical User Interface," NASA TM 108791,

October, 1993.

37.

Rogers, S. E., Roth, K., Nash, S. M., Baker, M. D., Slotnick, J. P., Whitlock, M.,and Cao, H. V.,"Advances in Overset CFD Processes Applied to Subsonic High-Lift

Aircraft," AIAA Paper 2000-4216, AIAA 18th Applied Aerodynamics Conference, Denver,

Colorado, August, 2000.

38.

Parks, S. J., Buning, P. G., Steger, J. L., and Chan, W. M., "Collar Grids for

Intersecting Geometric Components Within the Chimera Overlapped Grid Scheme,"

AIAA-91-1587, Proceedings of the AIAA 10th Computational Fluid Dynamics Conference,

Honolulu, HI, June 24-26, 1991.

39.

Chan, W. M. and Meakin, R. L.,"Advances Towards Automatic Surface Domain

Decomposition and Grid Generation for Overset Grids," AIAA Paper 97-1979, Proceedings

of the AIAA 13th Computational Fluid Dynamics Conference, Snowmass, Colorado, 1997.

40.


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Chan, W. M. and Gomez, R. J.,"Advances in Automatic Overset Grid Generation Around

Surface Discontinuities," AIAA Paper 99-3303, Proceedings of the AIAA 14th

Computational Fluid Dynamics Conference, Norfolk, Virginia, 1999.

41.

Chan, W. M. and Buning, P. G., "Surface Grid Generation Methods for Overset Grids,"

Computers and Fluids, 24, No. 5, 509--522, 1995.

42.

Chan, W. M., Gomez, R. J., Rogers, S. E. and Buning, P. G., "Best Practices in

Overset Grid Generation," AIAA Paper 2002-3191, 32nd AIAA Fluid Dynamics Conference,

St. Louis, Missouri, June, 2002.

43.

Pandya, S. A., Chan, W. M., Kless, J.,"Automation of Structured Overset Mesh

Generation for Rocket Geometries," AIAA Paper 2009-3993, June, 2009.

44.

Sponsors

Funding for this work has been provided by the NASA Constellation Program under the Ares, Ground

Operations, and Simulation-Assisted Risk Assessment (SARA) projects; and the DOD HIARMS project. Past

sponsors include the NASA CICT/CNIS Program the NASA High Performance Computing and

Communications Program, the DOD High Performance Computing Modernization Program under the CHSSI

CFD-4 Project, the Advanced Subsonic Technology Program, and the Space Shuttle Program.

Software Request Procedure

This software package can be requested and used by U.S. citizens and permanent residents belonging to a

U.S. organization. The request can be made from

"https://www.nas.nasa.gov/cgi-bin/software/start "

Follow the links for Chimera Grid Tools and fill out an appropriate Software Usage Agreement form

depending on the user's affiliation, and fax the form back to the Ames Software Release Authority (FAX:

650-604-7486).

Notices and Disclaimers

The following notices and disclaimers apply to all modules and libraries of the Chimera Grid Tools software

package.

NOTICES

Chimera Grid Tools, Copyright 2004, 2007, 2010 United States Government as represented by the

Administrator of the National Aeronautics and Space Administration. No copyright is claimed in the United

States under Title 17, U.S. Code. All Other Rights Reserved.

Unique Surface Using Ranked Polygons (USURP) distributed under license by the Pennsylvania State

Research Foundation. Portions of USURP created by David Boger are Copyright 2005 The Pennsylvania

State University. All Rights Reserved.

This software may be used, copied, and provided to others only as permitted under the terms of the contract


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or other agreement under which it was acquired from the U.S. Government. If you have received this

software for use under a Government Contract, Cooperative Agreement or Grant the software is for federal

government research purposes only, and may not be further distributed to third parties. Neither title to nor

ownership of the software is hereby transferred. This notice shall remain on all copies of the software.

DISCLAIMERS

THE SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY KIND, EITHER

EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY

THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF

MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR FREEDOM FROM

INFRINGEMENT, ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE, OR ANY

WARRANTY THAT DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SOFTWARE. IN

NO EVENT SHALL THE UNITED STATES GOVERNMENT, OR ITS CONTRACTORS OR

SUBCONTRACTORS, BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO,

DIRECT, INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING

FROM, OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON

WARRANTY, CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED

BY PERSONS OR PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINEDFROM, OR AROSE OUT OF THE RESULTS OF, OR USE OF, THE SOFTWARE or services provided

hereunder. THE UNITED STATES GOVERNMENT DISCLAIMS ALL WARRANTIES AND

LIABILITIES REGARDING THIRD PARTY SOFTWARE, IF PRESENT IN THE NASA GENERATED

SOFTWARE, AND DISTRIBUTES IT "AS IS."

RECIPIENT AGREES TO WAIVE ANY AND ALL CLAIMS AGAINST THE UNITED STATES

GOVERNMENT AND ITS CONTRACTORS AND SUBCONTRACTORS, AND SHALL INDEMNIFY

AND HOLD HARMLESS THE UNITED STATES GOVERNMENT AND ITS CONTRACTORS AND

SUBCONTRACTORS FOR ANY LIABILITIES, DEMANDS, DAMAGES, EXPENSES OR LOSSES

THAT MAY ARISE FROM RECIPIENT'S USE OF THE SOFTWARE, INCLUDING ANY DAMAGESFROM PRODUCTS BASED ON, OR RESULTING FROM, THE USE THEREOF.

IF FURTHER RELEASE OR DISTRIBUTION OF THIS SOFTWARE OR TECHNICAL DATA DERIVED

FROM THIS SOFTWARE IS PERMITTED, RECIPIENT AGREES TO OBTAIN THIS IDENTICAL

WAIVER OF CLAIMS, INDEMNIFICATION AND HOLD HARMLESS AGREEMENT WITH ANY

ENTITIES THAT ARE PROVIDED WITH THE SOFTWARE OR TECHNICAL DATA DERIVED FROM

THE SOFTWARE.

Last modified: Tue March 09 16:26:00 2010


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