NekToolKit: a light-weight support suite for Nek5000

Author: Kento Kaneko ([email protected])

Date: 2024-05-17

NekToolKit is (currently) a suite of Matlab functions enabling processing of Nek5000-related files. Development is in the early stage and no guarantee of backwards-compatability between commits (alpha). Any feedback / suggestions is welcomed!

Workflow

This project's original motivation was for a fast TTFP (Time-to-first-plot), measured in GUI manipulation time and not compute-time.

First, NekToolKit/matlab should be added to path and then call NekSnaps to create snapshots object which allows easy plotting. An example shown below:

addpath('~/NekToolKit/matlab'); % replace with /path/to/NekTookKit/matlab

% first argument optional if 'SESSION.NAME' exists,
% second argument optional
s = NekSnaps('casename',1:10);

s.first('u1') % plot the first component of velocity for the first snapshot

% plot the velocity magnitude for the first 10 snapshots
for i=1:10; s.show(i,'u_abs'); end

The initialization process can be scripted by adding the path in setup.m and adding conveninece script:

/Applications/MATLAB_R2023b.app/bin/matlab -nosplash -nodesktop -r 's=NekSnaps(); s.first()'

Supported fields

• 'x1', 'x2': mesh position components
• 'u1', 'u2': velocity components
  • 'u_abs': velocity magnitude
  • 'u_div': velocity divergence
  • 'u_div': vorticity
• 'p': pressure
  • 'p_lap': pressure Laplacian
• 't': temperature
• 's1', 's2', ... : passive-scalars

Future Plans

On TODO

• Frame rendering
• Field dump
• Support for opposite endianness

Considered

• Pre-processing (.rea, .re2)
• Slicing for n2to3-extruded mesh
• Integration
• Mesh quality
• Python support
• Julia support

Long-Shot

• Direct-stiffness (reading from .map / ma2)
• Solves
• GUI