Splash-free urinals: Design through physics and differential equations

88 points, 105 comments from yesterday:

https://news.ycombinator.com/item?id=43668957

This comes close to my hobby science of 20 yrs+! Toilet statistics! What distribution do people follow in choosing doors? Linear (no!), Negative Binomial (I think so, but which parameters? And do the number of stalls matter?), Gaussian? Do cleaners clean all stalls proportionally? Which urinal to choose? Never pick a neighbor? Is there an optimization there? Then the economics part…

Regarding OP. Splash isn’t the only factor in urinals alas. Ease of cleaning and the ability to stop junk. I’ve seen innovative splash less designs in bars. Usually a plastic cup upside down will seriously mess up the flow. People throw paper and gum and cigarettes in them. You need it splash free And robust.

I think it's not a coincidence that they decided to publish on PNAS...

The study was aptly supported in part by the University of Waterloo.

If you expect to see the new designs in public restrooms anytime soon, though, you should curb your enthusiasm.

I'll see myself out …

What did I just read? I did not put some much effort for my bachelors project lol.

Possibly won't be very popular in all of the US: Urinals seem to be optimized for maximum noise (in some parts of Europe for minimum sound). Different design objectives. Or in some Southeast Asian countries, regular (small) toilets are optimized to be able to be flushed with a single bowl of water: Standing in front of them will almost always spray in all directions (but hot temperatures will usually take care of it quickly enough).

Is it normal not to include the source of the governing equation (the ODE in equation 4)? I could not find any mention of it.

Funded by Ray Dalio [0]?

0.https://equitymates.com/general/how-the-worlds-largest-hedge...

I am pretty sure the urinal in my gym is designed to be splashy to inhibit people using it. Saves on the water bill. I can't think of any other reason...

I think the European urinals already follow the proposed designs closely. They only compare to very old chunky designs.

In a restroom with commercial contemporary models, cardboard rectangles were placed under each.

Maybe of all there was none to fault; it was just the physics of poor design.

Next paper from the authors: a form that maximizes splash to prevent public urination