Andrew Wickert

Andrew Wickert

McKnight Land-Grant Assistant Professor
Department of Earth & Environmental Sciences
Faculty, Saint Anthony Falls Laboratory
Associate, Institute on the Environment

Laminar and turbulent flow

Does the flow remain smooth and orderly or does it devolve into the chaos of a hundred kindergartners who all speak different languages racing around a playground trying to catch butterflies?

Learning Goals

  • Understand the difference between laminar and turbulent flow.
  • Know what the Reynolds number is and how it can be used to find whether a flow is likely to be laminar or turbulent.
  • Know how to calculate the Reynolds number in practical situations.
  • Know that flow in typical natural rivers is very turbulent.

Video lecture

Course notes (blank)

Flow mechanics PDF, last updated 2020.10.23

Video examples of laminar and turbulent flow

Water jet that is transitional from laminar to turbulent.

Be warned! Fjord-cat ran to the door to ask to be let outside shortly after this video started! It’ll make sense why… (Alas, it was the day after the October 2020 snowstorm when I played it, and she had to wrestle with the idea of getting her paws wet and cold.)

Note how the dye streams are visible (laminar) and turn into a well-mixed cloud (turbulent). The folks running the experiment are changing its velocity only slightly.

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