ENGINEERING TRIPOS PART IIB – 2012/2013
Module 4A12 - Turbulence
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Leader:
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Prof. P. A. Davidson
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Timing:
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Lent Term
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Prerequisites:
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3A1 assumed and 3A3 useful, 4A8 useful
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Structure:
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16 lectures (including examples classes)
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| Assessment: |
Material / Format / Timing / Marks
Lecture Syllabus / Written exam (1.5 hours) / Start of Easter Term / 100 %
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AIMS
Turbulence is a common feature of fluid flows in the atmosphere and the ocean,
in aerodynamics and combustion. This module aims to introduce the physical
basis of turbulence as well as its practical implications for engineers. Vortex
dynamics is identified as controlling energy transfers between different scales
in a turbulent flow and the module aims to introduce the basic rules of vortex
dynamics.
LECTURE SYLLABUS
Turbulence and Vortex Dynamics (16L)
- Introduction to turbulence:
Pictures of turbulence. Universality of turbulence in flows as the final
result of instabilities. Engineering consequences.
- Some simple illustrations
of vortex dynamics: The persistence of rotation (angular momentum) in
flows. Another description of fluid dynamics: the vorticity equation. Lift
and induced motion, with application to aerodynamics and hovering insects.
Swirling flows with application to tornadoes, hurricanes and tidal
vortices.
- Basic concepts in
turbulence theory: Order from chaos - Reynolds decomposition and Reynolds
equation. Kinetic energy - Production and Dissipation. Introduction to the
different scales in Turbulence, from the integral scale to Kolmogorov's
micro-scale. Wall-bounded shear flows. Vortex dynamics at work at the
large and small scales (worms).
- Phenomenological models of
turbulence: Prandlt's Mixing length and k - e model: their assumptions and
limitations. Other models. What can be expected from these turbulence
models in terms of velocity and heat transfer.
- Current trends in
industrial fluid mechanics.
OBJECTIVES
On completion of the module students should:
- Be aware of the turbulent
nature of most flows of interest to engineers and its influence on the
transfer processes involving momentum, heat and mass;
- Be able to interpret fluid
motion in terms of the creation and transport of voricity;
- Understand energy transfer
between mean flow and turbulent fluctuations (Reynolds stresses);
- Understand energy transfer
between the different scales of turbulence and the mechanism of
dissipation;
- Be aware of the more common
phenomenological models of turbulence currently used by engineers and of
their underlying assumptions and limitations.
REFERENCES
Please see the Booklist for Group A Courses for references for this module.
Last updated: June 2012
teaching-office@eng.cam.ac.uk
