Chapter 2
Computation of the base flow

Cylinder-Base.xml can be found inside the $NEKTUTORIAL/base folder. This is the Nektar++ file generated using $NEK/NekMesh and augmented with all the configuration settings that are required. In this case, CFL conditions can be particularly restrictive and the time step must be set around 8 × 10-4. We will be using Reynolds number Re = 42 for this study.

The supplied file Cylinder-Base.bse is the converged base flow required for the analysis and is the result of running Cylinder-Base.xml. To have a steady solution it was necessary to evolve the fields for a non-dimensional time τ ≥ 300 and it is very important to be sure that the solution is steady. This can be verified by putting several history points on the centre line of the flow and monitoring their variation.

Task: 2.1 Convert the base flow into VTK format and visualise the profile of the flow past a cylinder in Paraview .

The base flow should look like the one in figure 2.1.


Figure 2.1: Base flow for the cylinder test case