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Introduction to turbulence/Study questions

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Nature of turbulence
Statistical analysis
Reynolds averaging
Study questions

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Questions related to the nature of turbulence

  1. Observe your surroundings carefully and identify at least ten different turbulent phenomena for which you can actually see flow patterns. Write down what you find particularly interesting about each.
  2. Talk to people (especially engineers) you know (or even don’t know particularly well) about what they think the turbulence problem is. Decide for yourself whether they have fallen into the trap that Professor Jones talks about in the quotation used in this text.
  3. Some believe that computers have already (or at least soon will) make experiments in turbulence unnecessary. The simplest flow one can imagine of sufficiently high Reynolds number to really test any of the theoretical ideas about turbulence will require a computational box of approximately (10^5)^3, because of the large range of scales needed. The largest simulation to-date uses a computational box of (10^3)^3, and takes several thousand hours of processor time. Assuming computer capacity continues to double every 1.5 years, calculate how many years it will be before even this simple experiment can be done in a computer.
  4. The famous aerodynamicist Theodore von Karman once said: “A scientist studies what is; an engineer creates what has never been.” Think about this in the context of the comments in Chapter 1, and about the differing goals of the scientist and the engineer. Then try to figure out how you can plot a life course that will not trap you into thinking your own little corner of the world is all there is.
  5. Think about the comments that ideas become accepted simply because they have been around awhile without being disproved. Can you think of examples from history, or from your own personal experience? Why do you think this happens? And how can we avoid it, at least in our work as scientists and engineers?


This text was based on "Lectures in Turbulence for the 21st Century" by Professor William K. George, Professor of Turbulence, Chalmers University of Technology, Gothenburg, Sweden.

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