Cats2D Multiphysics > Overview > Control file

Cats2D control file format

Cats2D requires a text input file named <jobtitle>ctrl.txt (default is flowctrl.txt) to define a physical problem to be solved. Simple commands are written to select a coordinate system, to define governing equations for each material, to apply boundary conditions to boundaries, and to define flags that control various aspects of code behavior. Commands and comments can be given in any order, and are written in a syntax that is easy to understand. The lid-driven cavity, for example, requires only two commands:

flow(on)
bc(u-dirichlet(3,(3,0,0,0),(1,1.0)))

Here is a more complicated example, the EFG (edge-defined film-fed growth) problem:

geometry(axisymmetric)
reference-frame(translational,2)

multiphase(3)
material(1,3,3,4,5,liquid)
material(2,2,1,2,solid)
material(3,1,6,graphite)

% %%%%%%%%%%  ENERGY  %%%%%%%%%%%

energy(on)

% growth interface
bc(latent-heat(1,(0)))

% die bottom and inlet temperature
bc(t-dirichlet(9,(3,1,1,0)))
bc(t-dirichlet(4,(3,1,1,0)))

% furnace to melt, crystal side, die, crystal end
bc(t-robin(2,(0)))
bc(t-robin(7,(0)))
bc(heat-flux-user(8,(2,17,5)))
bc(heat-flux-user(10,(2,17,5)))

% %%%%%%%%%%  FLOW  %%%%%%%%%%%

flow(on,1)

% meniscus
bc(capillary-traction(2,(2,0,0)))

% density change at interface
bc(continuity(1,(2,1,1)))

% die inlet
bc(outflow(4,(1,0)))

% %%%%%%%%%%  MESH  %%%%%%%%%%%

mesh(on)

% growth interface
bc(isotherm(1,(0)))

% meniscus 
bc(kinematic(2,(2,0,0)))

% growth angle condition computes y-position of trijunction
bc(angle(2,(3,1,2,0)))

% side of crystal
bc(slope(8,(1,0)))