...fascinating stuff, but that's at sea level of course. Go to 35,000' and the air density drops to less than 1/100th of the sea level value. So even at 600 mph, according to the back of my beer mat, the mass flow rate only equates to about 15 kgs per second.
This seems incredibly low - how can you impart enough energy to 15 kgs of air to get it to produce thousands of kilos of thrust? (albeit that altitude thrust ratings are obviously massively less than at sea level).
While we're off the subject, how much mass-flow is (was) going through the J58 of an SR71 at 80,000' every second, even if it is bowling along at Mach 3? A few ounces, you'd think.
(Also, if you're burning (say) a kilo per second in the big fan, isn't 1 kilo of fuel to 15 kilos of air a bit rich?!).