Navigate: ← Test case channel 2D

Poisueille flow in a channel 2D using drtBGK collision scheme

In this example, we will investigate the Poiseuille flow in a plain 2D channel using the dual relaxation time bgk (drtBGK) collision scheme with a second order regularization.

This collision scheme is called as below in the identify table. relaxation = 'drt_bgk'

The fluid table in musubi.lua should include the following --! [Fluid] fluid = { kinematic_viscosity = nu_phy, drt_taun = 0.55 -- default = 0.70 } --! [Fluid]

The taun has a default value of 0.70 which can be overwritten from input. This represents a relaxation time, therefore must be greater than 0.50 for stability. If the value inserted does not produce a stable result, please decrease it towards 0.50. For this test case with the original seeder.lua file, the default value of 0.70 does not produce a stable run.

A detailed description of test case can be found in the parent directory Description of test case channel 2D.

Generating mesh

Define geometry information

Define spatial objects

Running simulation

Define flow parametes

Define collision parameter

Define boundary condition

Post-processing

Here are the results from the simulation. To create them, double the number of elements in height (nHeight=32) in seeder.lua.

Velocity along the height of the channel:

Pressure across the length of the channel:

Wall shear stress along the height of the channel:

To create these plots, run python plot_track.py to create the plots. Before running the plot script, open 'plot_track.py' and update path to Gleaner script in 'glrPath'. Download Gleaner script using hg clone https://geb.sts.nt.uni-siegen.de/hg/gleaner