Thanks to Celine (who defended her Master’s thesis today, and is headed back to Switzerland… Good Bye!), Mikey, Celine, Ian, and I managed to get a grand tour of the NASA Ames wind tunnels a few weeks ago. We toured through three tunnels — a 20×40, a 40×80, and the massive (world’s largest!) 80×120ft.
Our tour guide was a fantastic, animated fellow who was full of stories, history, and enthusiasm for the wind tunnels. “Astrobiology institutes will come and unfortunately go, but these wind tunnels will be here and will be used for many years to come,” was a quote that stuck in my mind. He shared many interesting technical details — for example, he explained why the the outlet of the test cell is surrounded by small airfoils. Apparently they create vortices that draw air into the center of the channel as the channel expands from the test cell section to the full diameter of the tunnel. This prevents the air from losing velocity when it expands too quickly — this leads to turbulent flow that can lead to all kinds of trouble in the wind tunnel.
I also thought it was very cool that the test cell area itself was surrounded with foam that acts as an acoustic damper, thereby creating an nearly anechoic chamber. As our tour guide walked out into the test cell, his voice got quieter and quieter until it was nearly impossible to hear him unless he was speaking directly in my direction. The only echos we could hear were delayed about two seconds because they had to travel out of the test cell, all the way down the tunnel and back again to reach our ears.
Mmmm… fluid dynamics. Yum!