Here I wrote a Javascript application to look at the logistic mapping and zoom and pan around the graph that is usually produced. Try it at: https://jkwillis.info/logmap/demo.html The usual version is monochromatic and shows how the function decays to chaos, after a few bifucations etc. But there is […]

I worked for a few years on this project and will fill out things here as we go. Here follows an example of one kind of model output for smolt leaving their natal river.

The Thames Tideway Tunnels are a new Super Sewer for London. It has been built directly underneath the river Thames and uses the high tidal energy of the Thames to drive sewage out of London. I was involved in gaining planning approval when working with Turnpenny Horsfield Associates […]

Here are some examples of swimming robots we have built over the past few years,

These models were made to predict the changes to fish habitat that might result from developments in rivers. By small scale I mean rivers 2 m wide to 20 m wide over distances of less than a few kilometres. Usually we were employed to look at the changes […]

Here’s some work I did with others for a paper led by Martyna Syposz. The paper is open access and available here. The requirement was to track birds as they moved across each frame of a video of thermal images taken with a modern infrared camera. In the […]

I made these models originally to avoid using mathematics. I wanted to work out how flexible springs would have to be to wriggle the tail of a fish that swam with the standard theoretical wave form. The springs would need to be off-set from the centre line of […]

I’ve made a load of models of small living particles being moved around in hydrodynamic models (have a look at a few of the posts here). Mostly larvae, but also seeds and other propagules. These things can swim, and they can change their buoyancy. They can alter their […]

Here’s a very short summary of a complex load of modelling that I was involved with. The basic model is a cellular model on a grid – each grid square has a stack of grains of sand on it. Then each step of the model involves a grain […]

Here I made a few models for a fisher (Andrew Scudder). At the time NOAA were producing two week forecasts of the currents in Prince William Sound in Alaska. Andrew had the idea that we might be able to model salmon returning to their natal rivers by using […]