CGNS Extensions

Reno, 2002

Introduction

• New extensions:
  • Links
  • User Defined data
  • Chemistry & species
• Implemented by Intelligent Light (under contract with NASA Langley)

Links

• Capability has always been there, but only possible to create them with ADF calls
• New API routines have been written:
  • cg_link_write (nodename, filename, name_in_file)
  • cg_link_read (filename, link_path)
  • cg_is_link (path_length)

Example of creating a link

While you are in file 1:

   filename='file 2'
   name_in_file='GridBase/Zone 1/GridCoordinates'
   call cg_goto_f(index,ibase,ier,'Zone_t',1,'end')
   call cg_link_write_f('GridCoordinates',filename,name_in_file,ier)

User-defined data

• Currently difficult to add arbitrary data (not covered by SIDS) to CGNS file when using API
• Needed, e.g., to hold required code-specific information that is not intended to be used by others
• Identified by the tag: UserDefinedData_t
• Is supported under most existing nodes
• Arbitrary dimensions and dimension values are supported
• Arbitrary number of UserDefinedData_t nodes allowed under each node
• Arbitrary number of DataArrays allowed under each UserDefinedData_t node
• New API routines have been written:
  • cg_user_data_write (user_data_name, index)
  • cg_user_data_read (index, user_data_name)
  • cg_nuser_data (nuserdata)

Example of writing user-defined data

   real*8 data1(3)
   real*4 data2(3,3)
   call cg_goto_f(index,ibase,ier,...,'end')
   call cg_user_data_write_f('Extra',index,ier)
   call cg_goto_f(index,ibase,ier,...,'UserDefinedData_t',index,'end')
   call cg_array_write_f('MyData1',RealDouble,1,3,data1,ier)
   indx(1)=3
   indx(2)=3
   call cg_array_write_f('MyData2',RealSingle,2,indx,data2,ier)

Chemistry & species

• Still in process, but nearing completion
• Summary of changes:
  • Under FlowSolution, define new field quantity data-name identifiers (e.g.: MassFractionH2O)
  • Under FlowEquationSet, modify GasModel to allow several additional types (e.g., CaloricallyPerfect, RedlichKwong)
  • Under FlowEquationSet, allow new node ThermalRelaxationModel_t (e.g., type = Frozen, ThermalEquilib)
  • Under FlowEquationSet, allow new node ChemicalKineticsModel_t:
    • e.g., type = Frozen, ChemicalEquilibCurveFit
    • define several data-name identifiers for DataArray_t nodes (e.g., MolecularWeightH2O)
• If needed, other FlowEquationSet information to be stored in Descriptor nodes