04-20-2020, 11:16 AM
Relevant quote to the PeterB/Sarcany debate from Roger's NY Times link:
NYTimes wrote: Why is it that small droplets and viral particles don’t typically land on our clothing?
I asked Dr. Marr to explain further, since we’re all getting a mini lesson in aerodynamics.
“The best way to describe it is that they follow the streamlines, or air flow, around a person, because we move relatively slowly. It’s kind of like small insects and dust particles flowing in the streamlines around a car at slow speed but potentially slamming into the windshield if the car is going fast enough,” said Dr. Marr.
“Humans don’t usually move fast enough for this to happen,” Dr. Marr continued. “As we move, we push air out of the way, and most of the droplets and particles get pushed out of the way, too. Someone would have to spray large droplets through talking — a spit talker — coughing or sneezing for them to land on our clothes. The droplets have to be large enough that they don’t follow the streamlines.”
So, if you’re out shopping and somebody sneezes on you, you probably do want to go home, change and shower. But the rest of the time, take comfort that your slow-moving body is pushing air and viral particles away from your clothes, a result of simple physics.