Chapter 5
FieldConvert

FieldConvert is a utility embedded in Nektar++ with the primary aim of allowing the user to convert the Nektar++ output binary files (.chk and .fld) into a format which can be read by two common visualisation softwares: Paraview/VisIt (.vtu format) or Tecplot/VisIt (.dat or .plt formats). FieldConvert also allows the user to manipulate the Nektar++ output binary files by using some additional modules which can be called with the option -m which stands for module. Note that another flag, -r (which stand for range) allows the user to specify a sub-range of the domain on which the conversion or manipulation of the Nektar++ output binary files will be performed.

Almost all of the FieldConvert functionalities can be run in parallel if Nektar++ is compiled using MPI (see the installation documentation for additional info on how to implement Nektar++ using MPI). 1

 5.1 Convert .fld / .chk files into Paraview, VisIt or Tecplot format
 5.2 Convert field files between XML and HDF5 format
 5.3 Range option -r
 5.4 FieldConvert modules -m
  5.4.1 Smooth the data: C0Projection module
  5.4.2 Calculate Q-Criterion: QCriterion module
  5.4.3 Add composite ID: addcompositeid module
  5.4.4 Sum two .fld files: addFld module
  5.4.5 Combine two .fld files containing time averages: combineAvg module
  5.4.6 Concatenate two files: concatenate module
  5.4.7 Equi-spaced output of data: equispacedoutput module
  5.4.8 Extract a boundary region: extract module
  5.4.9 Compute the gradient of a field: gradient module
  5.4.10 Extract a plane from 3DH1D expansion: homplane module
  5.4.11 Stretch a 3DH1D expansion: homstretch module
  5.4.12 Inner Product of a single or series of fields with respect to a single or series of fields: innerproduct module
  5.4.13 Interpolate one field to another: interpfield module
  5.4.14 Interpolate scattered point data to a field: interppointdatatofld module
  5.4.15 Interpolate a field to a series of points: interppoints module
  5.4.16 Isocontour extraction: iscontour module
  5.4.17 Show high frequency energy of the Jacobian: jacobianenergy module
  5.4.18 Calculate mesh quality: qualitymetric module
  5.4.19 Extract mean mode of 3DH1D expansion: meanmode module
  5.4.20 Project point data to a field: pointdatatofld module
  5.4.21 Print L2 and LInf norms: printfldnorms module
  5.4.22 Computes the scalar gradient: scalargrad module
  5.4.23 Scale a given .fld: scaleinputfld module
  5.4.24 Time-averaged shear stress metrics: shear module
  5.4.25 Boundary layer height calculation: surfdistance module
  5.4.26 Calculate vorticity: vorticity module
  5.4.27 Computing the wall shear stress: wss module
  5.4.28 Manipulating meshes with FieldConvert
 5.5 FieldConvert in parallel
 5.6 Processing large files in serial
  5.6.1 Using the nprocs and procid options
  5.6.2 Using the –part-only and –part-only-overlapping options