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Salah Kouhen

Salah Kouhen

A PhD student at Oxford. Interested in turbulence, physics generally and a mix of many other things.

Von Kármán vortex street Lattice Boltzmann method sim

Von Kármán vortex street Lattice Boltzmann method sim

A von Kármán vortex street happens when fluid flows past a cylindrical obstruction. You get a series of vortices that march down flow. I wrote a Lattice-Boltzmann method solver in c# to simulate such a scenario. It suffers from numerical instability but if the velocity is raised slowly enough, you

What's been happening? (Part 2)

What's been happening? (Part 2)

This is the second of two posts in which I try to give a proper answer to "what's been happening?". I am attempting to give an overall picture of how things became the way they are. Part 1 was on prehistory and started with the big

What's been happening? (Part 1)

What's been happening? (Part 1)

With these two posts I am going to try and give a good answer to the question of "what's been happening?". It can be difficult to get an overall picture of how things became the way they are. That is what these posts attempt to provide.

Rain before 7, fine by 11

Rain before 7, fine by 11

You may have heard this proverb before. It's a British saying based on our changeable weather. If you live here, you probably noticed that heavy rain will often clear up by noon - or at least weaken considerably. But how true is this observation really? Grey and rainy

Starting a visual artistry journey: working with shaders

Starting a visual artistry journey: working with shaders

I love the way fluids move, you can probably relate to that. The beautiful swirling patterns you see when washing the dishes or those dramatic clouds over the ocean give life a bit of extra meaning. That is one of the reasons why I studied maths at university and definitely

On the political history of the Milky-Way Galaxy

This is a slightly more technical write up of the work in this blog post: Politics in the milky way. Summary Robin Hanson and colleagues recently proposed that “Grabby Aliens” could be the reason why humanity seems to have arrived cosmically early. In the Grabby alien model there is no

Liouville's equation

Liouville's equation

Summary I explain what the Liouville equation for the probability density function (PDF) is and its significance for weather prediction and chaotic systems more generally. I give its derivation, show how it is applied to a simple ODE and the Lorenz 63 system, I discuss its extension to the Fokker-Plank