Hi all! I defended my Ph.D. thesis back in 2019 and I also served as the creator and moderator for the subreddit r/FluidMechanics for a long time. I think with that I have gathered enough experience and courage to answer some of your queries. Some broad topics that I can answer questions on are:

  • computation fluid mechanics
  • scientific programming and HPC
  • nonlinear shallow water equations
  • statistical description of turbulence: spectra, energy budget etc.
  • experimental methods: PIV
  • stratified turbulence
  • academia
  • navigating your career pre- and post-Ph.D.

Ask away!

  • @derioderi0English
    1•1 year ago

    For geophysical CFD, what are typical values you deal with?

    • Viscosity
    • Density
    • Velocity
    • Reynolds number
    • Simulation timestep
    • Total simulation elapsed time
    • Total number of simultaneous unknowns solved for
    • @[email protected]OPMEnglish
      2•1 year ago

      There are two kinds of geophysical flow studies one can do. 2D simulations where you use models like shallow water equations. Then you deal with

      • Velocity
      • Reynolds number (which implies some viscosity)
      • Froude number (or gravity)
      • Rossby number (or Coriolis force from Earth’s rotation)
      • Total energy (so you know when it is in a statistically steady state)
      • Density only if you add many layer
      • Boundary conditions (only if it matters, can be avoided)

      You can also do a 3D simulation, but often we use the Boussinesq equations, in which density is approximated as a passive scalar.

      This is only the setup, but there is a rich set of phenomena one can aim to simulate with.

      • @derioderi0English
        1•1 year ago

        So are you treating the Earth’s crust as a shallow fluid layer? Or the mantle underneath? I would think the mantle is too thick for shallow water equations.

        • @[email protected]OPMEnglish
          1•1 year ago

          Usually for the troposphere or even the atmosphere and the ocean this can be a good model. As you said, I doubt if it can be used to represent lava flows under the earth - something a geologist would know and I am not one. 😀