> I didn't check what finite difference stencil or finite volume scheme the code uses, though I presume it's a lower order accurate one that probably has a fair amount of numerical viscosity.
It's just the basic second order central difference. It also uses a first order approximation to the Dirichlet and Neumann boundaries, so that additional error will diffuse throughout the simulation region. It doesn't use any approximation tricks for square roots etc., so given appropriate floating point semantics (as a physicist I have no clue what the shader language specifies there) you can still get realistic and accurate results by reducing the spatial and time steps, which is easily doable for a small 2D simulation on modern GPUs.
Ultimately, though, all the basic "best practices" for simulations of this kind - staggered grids, higher order derivative approximations, etc. - aren't very complicated and are well described in any CFD textbook. What really makes engineering CFD software complicated are things like handling complex geometries with dynamically refined meshes, efficiently solving the resulting linear equation systems at scale and coupling the fluid dynamics to other physical phenomena while retaining numerical stability and accuracy.
It's just the basic second order central difference. It also uses a first order approximation to the Dirichlet and Neumann boundaries, so that additional error will diffuse throughout the simulation region. It doesn't use any approximation tricks for square roots etc., so given appropriate floating point semantics (as a physicist I have no clue what the shader language specifies there) you can still get realistic and accurate results by reducing the spatial and time steps, which is easily doable for a small 2D simulation on modern GPUs.
Ultimately, though, all the basic "best practices" for simulations of this kind - staggered grids, higher order derivative approximations, etc. - aren't very complicated and are well described in any CFD textbook. What really makes engineering CFD software complicated are things like handling complex geometries with dynamically refined meshes, efficiently solving the resulting linear equation systems at scale and coupling the fluid dynamics to other physical phenomena while retaining numerical stability and accuracy.