ASTR-5400, Spring 2025

Instructor:	Steven R. Cranmer   (email, web page)
Instructor's Office:	Duane Physics D111 (main campus), LASP/SPSC N218 (east campus)
Course Times:	Spring 2025, Mon./Wed./Fri., 10:10-11:00 am
Location:	Duane Physics, Room E126
Office Hours:	TBD
Syllabus:	See the most up-to-date PDF version.

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Summary

This course provides an introduction to the dynamics of fluids (gases and liquids) relevant to astrophysical flows, planetary atmospheres and oceans, stars, galaxies, and other large-scale systems. Topics include potential flows and vorticity, the effects of viscosity and rotation, hydrostatic equilibria, acoustic and gravity waves, supersonic gas flows and shocks, and hydrodynamic instabilities. This is a core required course for APS graduate students, and it is the same course as ATOC-5400 and PHYS-5400.

Course Material

The primary "required readings" are my lecture notes, which will be posted on Canvas as the semester progresses. Other resources for this course include:

• A list of other online books and lecture notes that supplement my own material.
• Handout: useful math/physics formulae & constants that you're free to use for any work in this course (new for Spring 2025).
• For background & math review: undergraduate lecture notes from ASTR-2100 that cover:
  • trigonometry, vectors, coordinate systems, basic ODEs
  • partial derivatives, gradients, multiple integrals, div & curl, basic PDEs
• Some resources for scientific computing with Python.

Schedule

Below is a detailed schedule that provides a top-level outline of the material to be covered in each class session, along with various deadlines for assignments. On Canvas, I'll maintain a "daily topic log" that specifies exactly what was covered on each day, with links to the lecture notes and other materials.

1. Mon., January 13: Course introduction. "What is a fluid?" Overview of tensors, kinematics, and streamlines.
   • Homework 1 (problem set) assigned, due Fri., January 24.

2. Wed., January 15: "What is a fluid?" Overview of tensors, kinematics, and streamlines.

3. Fri., January 17: "What is a fluid?" Overview of tensors, kinematics, and streamlines.

   [Mon., January 20: Martin Luther King Holiday; no classes.]

4. Wed., January 22: Conservation of mass, momentum, and energy for ideal fluids.

5. Fri., January 24: Conservation of mass, momentum, and energy for ideal fluids.
   • Homework 1 due.
   • Homework 2 (problem set) assigned, due Wed., February 5.

6. Mon., January 27: Conservation of mass, momentum, and energy for ideal fluids.

7. Wed., January 29: Conservation of mass, momentum, and energy for ideal fluids.

8. Fri., January 31: Conservation of mass, momentum, and energy for ideal fluids.

9. Mon., February 3: Conservation of mass, momentum, and energy for ideal fluids.

10. Wed., February 5: Dynamical behavior of ideal fluids (with applications).
    • Homework 2 due.
    • Homework 3 (problem set) assigned, due Wed., February 19.

11. Fri., February 7: Dynamical behavior of ideal fluids (with applications).

12. Mon., February 10: Dynamical behavior of ideal fluids (with applications).

13. Wed., February 12: Dynamical behavior of ideal fluids (with applications).

14. Fri., February 14: Dynamical behavior of ideal fluids (with applications).

15. Mon., February 17: Dynamical behavior of ideal fluids (with applications).

16. Wed., February 19: Dynamical behavior of ideal fluids (with applications).
    • Homework 3 due.
    • Homework 4 (problem set) assigned, due Wed., March 5.

17. Fri., February 21: Dynamical behavior of ideal fluids (with applications).

18. Mon., February 24: Non-ideal fluids: collisions, viscosity, and conductivity.

19. Wed., February 26: Non-ideal fluids: collisions, viscosity, and conductivity.
    • Steve is traveling: TBD guest lecturer or pre-recorded video

20. Fri., February 28: Non-ideal fluids: collisions, viscosity, and conductivity.
    • Steve is traveling: TBD guest lecturer or pre-recorded video

21. Mon., March 3: Non-ideal fluids: collisions, viscosity, and conductivity.

22. Wed., March 5: Linear waves in fluids: acoustic, surface gravity, buoyancy.
    • Homework 4 due.
    • Midterm Project assigned, due Wed., March 19.

23. Fri., March 7: Linear waves in fluids: acoustic, surface gravity, buoyancy.

24. Mon., March 10: Linear waves in fluids: acoustic, surface gravity, buoyancy.

25. Wed., March 12: Linear waves in fluids: acoustic, surface gravity, buoyancy.

26. Fri., March 14: Linear waves in fluids: acoustic, surface gravity, buoyancy.

27. Mon., March 17: Linear waves in fluids: acoustic, surface gravity, buoyancy.

28. Wed., March 19: Linear waves in fluids: acoustic, surface gravity, buoyancy.
    • Midterm Project due.
    • Homework 5 (problem set) assigned, due Wed., April 9.

29. Fri., March 21: Linear waves in fluids: acoustic, surface gravity, buoyancy.

    [March 24-28: Spring Break; no classes.]

30. Mon., March 31: Compressible gas dynamics: supersonic flows and shocks.

31. Wed., April 2: Compressible gas dynamics: supersonic flows and shocks.

32. Fri., April 4: Compressible gas dynamics: supersonic flows and shocks.

33. Mon., April 7: Compressible gas dynamics: supersonic flows and shocks.

34. Wed., April 9: Compressible gas dynamics: supersonic flows and shocks.
    • Homework 5 due.
    • Homework 6 (problem set) assigned, due Wed., April 23.

35. Fri., April 11: Compressible gas dynamics: supersonic flows and shocks.

36. Mon., April 14: Compressible gas dynamics: supersonic flows and shocks.

37. Wed., April 16: Compressible gas dynamics: supersonic flows and shocks.

38. Fri., April 18: Fluid dynamics in rotating frames.

39. Mon., April 21: Fluid dynamics in rotating frames.

40. Wed., April 23: Fluid dynamics in rotating frames.
    • Homework 6 due.

41. Fri., April 25: Hydrodynamic instabilities.

42. Mon., April 28: Hydrodynamic instabilities.

43. Wed., April 30: Hydrodynamic instabilities.

    [Fri., May 2: Reading Day. Final Exam Week: May 3 to May 7.]