Author: Blair Johnson

Summer is passing far too quickly, as always, but progress is being made one day at a time.  My lab is almost fully complete (and it’s really really beautiful!), flume renovations are in the works, money is being spent on lovely new tools and devices, and research is happening. I got to see old friends and make new ones at conferences in June – first at the 8th  International Symposium on Environmental Hydraulics at Notre Dame, and then at the Association for the Sciences of Limnology and Oceanography meeting in Victoria, BC.  Next up will be the AGU Fall Meeting, once we have new experimental data!

In mid-June, I found out that my first real proposal was awarded, and so come spring 2019, we’ll be testing concrete median barriers. Woohoo!!  Wait, concrete median barriers and environmental fluid mechanics?  Why?  Well, during and after Hurricane Harvey in August 2017, there was heavy rain (an understatement) and terrible flooding.  There were areas where the concrete median barriers, which normally serve for crash protection between lanes of oncoming traffic, instead acted as dams and prevented floodwaters from draining across the highway.  There are phenomenal photos (I have no public ones from Texas, but here’s a photo/article of a similar event in Louisiana) where you can see half of the highway completely flooded up to the height of the barrier, while the other half is dry and open to traffic.  We are partnering with the Texas A&M Transportation Institute to design median barriers with holes in them, so the water can pass through efficiently and improve flood conditions (this is the hydraulics part!).  They still have to be structurally sound and crash proof, so once we develop a barrier capable of handling flood conditions, we also get to crash giant trucks into them and see how they hold up.  How cool is that.  No Navier-Stokes equations will be endangered during this process, but … it’ll be pretty awesome if we make something that works that then ends up on actual Texas highways.  Fingers crossed!

When I was considering my offer for UT last year, I forgot to really ask for a flume.  It seemed so natural – fluid mechanics professors should have flumes – that it didn’t even cross my mind.  I think I was so excited by the giant outdoor flume that I was satisfied anyway.  But luckily, the department realized – we already have a tilting glass research flume.  It was built in 1972 and hasn’t really been “run” as a flume in a decade or two (or more…), though it has had water in it since then, leaking like a sieve each time.  There were plastic chairs sitting in it, chipping paint, rust, drip marks, etc.  But seeing good bones on it, I couldn’t let it go to waste and have been plotting ways to bring it back to life over the past year.

Last week, my students Junior and Luisa set to work cleaning it and working with Jim Buttles of the Jackson School to see if we could get it to working order.  Electronics were inspected and repaired, and supposedly it would all work.  Yesterday was long-anticipated “flume day” where we planned to put water in it and run the pump, cross our fingers, toes, and everything possible, and … it ran!  They did all the work but let me push the button, which I was pretty pumped about, no pun intended.

Though we filled it with clean water, leftover mud was sitting in the recirculation pipe, so we had an impressively cloudy hydraulic jump (not really shown here, but you can imagine).  It smelled incredibly earthy, also a little like fire (46 year old dust needs to get brushed out of the control box!) but it worked and the water was rolling.

There’s still a lot of cleaning to do, updating the panels for full optical access, investigating the tilting mechanism, and beautifying the paint job a bit, but I remain optimistic!  Now we just need a name…

Since the lab now has water, it is almost a real fluid mechanics laboratory.  Check out a couple pictures of its evolution…

The original “before,” taken November 2017 –

Slightly less “before,” as of January 2018, complete with finished/insulated walls, a sink, an emergency shower and eyewash (which works — we tried!) and the base for a fume hood –

And finally, current photo as of March 2018, now with water along the walls, drop-down electrical outlets from the ceiling, ceiling insulation (gotta keep in the AC!) and waterproof floors –

Coming improvements include furniture, laser warning lights, and all the fixings to explore what science wants us to learn.  Stay tuned!

Renovations of the Johnson Environmental Turbulence (JET) Laboratory are presently underway with the lab opening in January 2018 when Prof. Johnson will arrive as an Assistant Professor in Civil, Architectural and Environmental Engineering at the University of Texas at Austin.  In the lab, we will break down complex environmental flows into their fundamental components to understand the driving fluid mechanics processes responsible for mixing and transport in the environment.  Even while living several hours from the coast, we can study phenomena such as breaking waves, stratified flows (whether by salinity, temperature, or some other density gradient), fluid-structure interaction, sediment transport, and countless others by developing unique laboratory facilities.  There will often be an emphasis on exploring turbulence as a key energetic contribution to shear stress, erosion, diffusion, and other processes.

While we are building new experimental facilities and renovating old ones, there will also be the potential for field work in Texas and across the US.  Although the primary expertise of the JET lab is experimentally-based, opportunities exist to collaborate with numerical modelers or to pursue joint experimental/numerical graduate research within the UT community and at other universities.

Please excuse (or enjoy!) the photos and videos of longhorns that are presently scattered around the site as updates are made.