I wrote a wave equation simulation in C# a while ago, and while everything works fine, I am running into the expected problem that my simulation boundaries (ie the edges of the grid) reflect the waves coming to them. Obviously I want to keep the grid of reasonable size, so I looked into what could be done to absorb the incident energy. So, I looked at papers addressing the problem. Problem is (as I find with a lot of academic papers), they are mathematically rigorous, but everyday useless. I'm in need of an easy 'n dirty solution that gets me 90% of the way in all situations, not one that gets me 100% under very specific circumstances. TLDR: Does anyone know of a quick and dirty ways of absorbing boundary reflections in a grid simulation?