The Very Spring and Root

An engineer's adventures in education (and other musings).

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Color for Dollars


From Karagiozis et al 2011


I didn’t work on this specifically, but this was the nature of my previous job. A humorous aspect was the fluid nature of the acronym CFD… formally it stands for Computational Fluid Dynamics, but others that captured the often tricky business of interpreting the results included Colorful Fluid Dynamics, Color For Dollars, Contours For Debate, and my personal favorite, Can’t Fucking Decide.


A little over a week ago, NASA’s Curiosity rover landed on Mars, the culmination of years of engineering. The mission’s landing, in particular, was the subject of intense scrutiny as Curiosity’s size necessitated some new techniques in the final segments of the landing sequence. As it hit the Martian atmosphere at 13,000 mph, the compression of the carbon dioxide behind the capsule’s shock wave slowed the descent.  At roughly 1,000 mph—speeds still large enough to be supersonic—Curiosity deployed its parachute. Shown above are the parachute in numerical simulation (from Karagiozis et al. 2011), wind tunnel testing at NASA Ames, and during descent thanks to the Mars Reconnaissance Orbiter. The simulation shows contours of streamwise velocity at different configurations; note the bow shock off the capsule and the additional shocks off the parachute. These help generate the drag needed to slow the capsule. For an interesting behind-the-scenes look at the wind tunnel testing for Curiosity’s parachute check out JPL’s fourpart video series. Congratulations to all the scientists and engineers who’ve made the rover a success. We look forward to your discoveries! (Photo credits: K. Karagiozis et al., NASA JPL, NASA MRO)