1st course on Lattice-Boltzmann methods - National University of Colombia - Dic2017

This repository will save notes from the 1st course on Lattice-Boltzmann methods at National University of Colombia.

Using this repository

To use this you just have to clone it using the following command

git clone https://github.com/ijpulidos/1stLBMunal.git

and then change to the new created directory

cd 1stLBMunal

where you can find the material distributed in different topics and dates.

LB method for waves - 2017-12-11

This first session was about creating a Lattice-Boltzmann method implementation for simple scalar waves. Go to directory LBwaves-2017-12-11 and just compile the code with

g++ LB_waves.cpp

which creates an executable file a.out and then run it using

./a.out

This will create a file called ondas.dat (sorry for the spanglish ;) with the data to be plotted using gnuplot, by running the gnuplot command and inside the gnuplot terminal, the following

set pm3d
unset surface
splot "ondas.dat"

LB method for Poisson eq. - 2017-12-12

The idea in this session was completing the code for the LBM for the Poisson equation.

Completing/implementing density charges and initial conditions and finding a power law for the error coefficient epsilon respect to the size of the system.

Solution

The solution to the exercise is in both LBPoisson_solution.ccp and my solution in LBPoisson_exercise.cpp. A plotting routine to plot the RMS error in terms of the size of the lattice is in the python script plotting.py

LBM for fluid dynamics - 2017-12-13

LBM for basic fluid dynamics, relatively low Reynolds numbers.

This would create a file called "fluid.dat" with x, y, vx, vy data in it. You can plot the data using gnuplot with the following commands for heat map:

set pm3d
unset surface
set view map
splot "fluid.dat"

or to see arrows

plot "fluid.dat" with vector

This LB for fluids code makes use of OpenMP parallel computing capabilities, to compile the code use the following command:

g++ -fopenmp LB_Fluidos_solucion.cpp

You can manually set the number of threads to use with the OMP_NUM_THREADS environment variable, example, for 4 threads you can run the code with:

OMP_NUM_THREADS=28  ./a.out

Assuming a.out is the executable file.