THE (NOT SO) GREAT PRETENDER.

Yesterday whilst perusing the internet for aerofoil inspiration I found several simulations of stuff blowing past and over a wing. I thought I bet I could make blender do that. I was up most of the night trying to prove myself right. I spent ages trying to get the smoke simulator to change colour with either speed or acceleration. I wasn't much bothered which as it was the pretty pattern I was after. I then remembered playing with particles ages ago, I was idly clicking on things to see what happened and I got a colour shift . Not something I was looking for at the time, it came in handy early doors this morning. Took me ages to work out what I'd clicked on but I found it.

I have had to fake a boundary box for this as otherwise the particles were going all over the place. On the left I have a thin plane emitting particles along the normal,  on the right a much bigger plane collecting them and supposedly killing them. You will see in the video that there is a shock wave on the aerofoil leading edge which is acceptable but there is another that runs back up from right to left which is not nice at all. This needs a lot of tweaking but it does seem to work. I will try and do a really posh one with more particles, smaller ones and I'll alter the angle of attack but more slowly. It takes the thing a while to stabilise. I'll also make the foil smaller in relation to the simulation bit. There is rarely a dull moment with Blender, I start off doing one thing and get sidetracked. Here is the video.

The first half is showing acceleration and the second velocity. The colours are awful but It really doesn't justify the time spent in the compositor sorting it and adding some blur. This is an Open GL* Render as, this will make you smile, non of what you are looking at is real only real stuff renders in either EEVEE or Cycles. Reality is a variable concept in the 3D world. It has much in common with politics in this respect.
Have fun and make the best of the coming week.

* Should anyone wonder where the OpenGL render engine has gone in Blender >2.80 then it is now under View-Render Viewport. Don't be tempted by the Workbench option in the render drop down menu it is something special for very special folk. It buggers everything up.