alt Hacker NewsUhh. I was taught that in university in the late 80s. Some surfaces have a lot of friction and if you add surface imperfections the turbulent airflow actually reduces drag.
Uhh. I was taught that in university in the late 80s. Some surfaces have a lot of friction and if you add surface imperfections the turbulent airflow actually reduces drag.
You learned something different then because this finding is that some kinds of additional roughness delay the transition to turbulent flow which is pretty clear in the article.