Module Catalogue 2024/25

Pre Requisite Comment

N/A

Co Requisite Comment

N/A

Aims

To present the application of fluid dynamics to the atmospheres and interiors of stars and planets, and to plasmas within and between galaxies.

Module summary:

Fluid dynamics typically becomes more challenging, and therefore more interesting, as the scale of the system under consideration is increased. This module concerns the very largest-scale fluid systems -- those of planets, stars, galaxies and the inter-galactic medium. On such scales the effects of gravity, rotation and magnetism become increasingly important, as does the complexity of fluid behaviour.

In this module we will study the physical processes that operate in geophysical and astrophysical fluids. We will describe how the nature of waves and turbulence is altered in the presence of gravity, rotation and magnetism.

Outline Of Syllabus

Revision of hydrodynamics and magnetohydrodynamics (MHD). Turbulent flows. The vorticity and induction equations. Conservation laws. Compressible flows, hydrostatic equilibrium, buoyancy, self-gravity. Convective and gravitational instabilities.
Rotation: the centrifugal and Coriolis forces, inertial waves, Ekman and Rossby numbers, the Taylor-Proudman theorem, Ekman layers. Conservation of potential vorticity. Kelvin, Poincare and Rossby waves in a rotating homogeneous fluid. Geostrophic adjustment. Barotropic instability. Large-scale wind driven ocean circulation.
Magnetism: magnetic flux freezing, advection, stretching and compression of magnetic fields, the Lorentz force, force-free fields.

Intended Knowledge Outcomes

Students will know:
- the conservation laws for energy, (angular) momentum, vorticity and magnetic flux;
- the significance of gravity, rotation and geostrophic balance in planetary flows;
- the role of turbulence in geophysics and astrophysics;
- the basics of atmospheric dynamics on Earth and other planets;
- the physical parameters of gas flows in galaxies and intergalactic space.

Intended Skill Outcomes

Students will be able to:
- obtain dispersion relations for inertial and gravity waves;
- perform stability analyses for a variety of physical systems;
- quantify and describe mathematically the relevant physical processes in geophysics and astrophysics;
- apply various techniques for solving fundamental equations of HD and MHD in GAFD applications.

Students will develop skills across the cognitive domain (Bloom's taxonomy, 2001 revised edition): remember, understand, apply, analyse, evaluate and create.

Teaching Rationale And Relationship

The teaching methods are appropriate to allow students to develop a wide range of skills, from understanding basic concepts and facts to higher-order thinking.

Lectures are used for the delivery of theory and explanation of methods, illustrated with examples, and for giving general feedback on marked work. Problem Classes are used to help develop the students’ abilities at applying the theory to solving problems.

Assessment Rationale And Relationship

A substantial formal unseen examination is appropriate for the assessment of the material in this module. The format of the examination will enable students to reliably demonstrate their own knowledge, understanding and application of learning outcomes. The assurance of academic integrity forms a necessary part of programme accreditation.

Exam problems may require a synthesis of concepts and strategies from different sections, while they may have more than one ways for solution. The examination time allows the students to test different strategies, work out examples and gather evidence for deciding on an effective strategy, while carefully articulating their ideas and explicitly citing the theory they are using.

The coursework assignments allow the students to develop their problem solving techniques, to practise the methods learnt in the module, to assess their progress and to receive feedback; these assessments have a secondary formative purpose as well as their primary summative purpose.

General Notes

N/A