EOSC 514 Introduction to Geological Fluid Mechanics, Spring 2012

 

Instructor: Mark Jellinek, EOS South 257

 

Text: Fluid Mechanics by Potter and Foss and some chapters from Engineering Fluid Mechanics by Crowe, Elger and Roberson

DVD: Multimedia Fluid Mechanics (MFM) by Homsy et al.

 

Introduction

Many problems in the Earth and planetary sciences involve fluid flow. Examples include the formation and subsequent thermal evolution of planets, the generation of planetary magnetic fields, the generation, rise, chemical differentiation, flow and eruption of magmas, sedimentation and mechanical erosion at riverbeds, the flow of groundwater, and circulation and mixing in the atmosphere and oceans.

 

This course presents a general introduction to the broad discipline of geological fluid mechanics. First and foremost, the course will introduce concepts and problem solving strategies in fluid mechanics. We will explore fundamental concepts including the continuum hypothesis, systems and control volumes, kinematics of fluids, integral and differential forms of the equations of motion, boundary conditions, dimensional analysis, scaling and stability. We will build understanding of core concepts in part by examining aspects of a number of special limits and features of flows occurring in geological situations such as boundary layers, potential flow, vorticity, lubrication theory, turbulence and waves. Geological flows are rich in their variety and complexity. They are never boring and they will constantly challenge the extent to which you understand the fundamentals. Why, for example, can you treat a snow avalanche composed of widely-spaced ice crystals and entrained air as Òa fluidÓ? In many cases, to make the geological problem ÒtractableÓ we have to make what you will probably regard as grotesque simplifications.  Such exercises enable us to classify or characterize behavior and build understanding in methodical ways.

 

Student learning objectives in order of increasing levels of learning

1) Solve simple problems in fluid mechanics. The student will acquire and apply necessary analytical skills  (mathematical and physical) to classify and solve simple given problems involving fluids.

2) Pose simple problems in geological fluid mechanics as models. The student will develop a personalized approach for constructing a conceptual and technical understanding of the mechanics involved in straightforward fluids problems.

3) Understand analog models of complex problems. The student will be able to reconstruct and understand existing mathematical representations of complicated problems involving fluids. The student will be able to discern and articulate verbally the strengths and weaknesses of such models.

4) Reduce complex (intractable) problems in geological fluid mechanics into some number of simpler (tractable) component problems. The student will be able to construct a model of a complex system and understand the strengths and limitations of such a model system. The student will be able to articulate verbally the value and limitations of such a model.

 

Assessment (5 parts)

1) Problem sets and Journal Review (20%)

Each problem set is designed to enhance your understanding of core material by looking at simple and sometimes ÒclassicalÓ problems. Viewed collectively, one of the aims of the problem sets is also to illustrate how fluids problems are classified and thus simplified such that they may be solved. Most assigned problems are drawn from the textbook, which has an engineering emphasis. These problems establish some basic principles. Complementary geological problems will be assigned, in part, to indicate the generality of the concepts being addressed. 

 

Solutions to all textbook problems are posted on the web.  Solutions to supplemental problems will be provided in class.  To receive full credit all problem sets must be self-graded with your own comments related to where you went wrong and why, what you did and why you did it.  No comments means no grade (i.e., 0 marks).  No late work is accepted.  Please read that twice. 

 

A format for each problem solved will be provided in class.  Please use this framework for each homework problem.  The point is to approach each problem in a systematic way.  This process will help you ultimately decide how you like to set up and solve problems.

 

 

All graduate students are required to review a journal article of their choice after consultation with me.  Undergraduate students are encouraged to do this as well but are not required.  We will discuss how to do this in greater detail as the due date approaches but here are a few guidelines for constructing your review:

 

  1. What is the real problem?  What question is the paper addressing?
  2. What is the analog problem?
  3. How is the problem posed mathematically?
  4. What is the strategy for solving the problem?
  5. What are the meaning and significance of the results?
  6. What are the strengths and limitations of the model (including the development of the model and the solution approach)?
  7. How might the model be realistically improved?

 

2) Quizzes (20%)

There will be 4 30 minute quizzes.  Quizzes will address basic concepts from lecture and the text. All material covered and assigned is open season. Students can bring 1 page (2 sides) of review notes to each quiz.  These notes must be handwritten.

 

3) Midterm Exam (15%). 

This will be a 1.5 hour exam on the evening of Feb. 20.  The exam is open book and you may use your 3 one-page cheat sheets. 

 

4) Final Exam (15%).

There will be a 3 hour take-home final exam due around December 11.

 

5) Final Project (30%)

The term project accounts for a substantial part of your assessment and will include a paper and a short presentation. Whereas exams, quizzes and problem sets are aimed at helping you build some familiarity and understanding of the vocabulary and core concepts of fluid mechanics the project will allow you to explore in detail an actual problem in geological fluid mechanics. For undergraduate students, a critical literature review of a problem is sufficient. Graduate students, however, must also describe a research project aimed at understanding some process or addressing an unsolved problem. All students are encouraged to attempt to actually solve a theoretical/numerical or experimental problem. Equipment, facilities and/or computers may be available. If appropriate students may also work in groups in order to work on more involved projects.  More details about the format of the paper and the talk will be provided later.

 

 

Downloads and links

Supplemental Lecture Notes

Numerical Computing with MATLAB (an online textbook)

Notes on the numerical solution of differential equations [PDF (76 KB)]

MATLAB script odeexamplemain.m

MATLAB function oneode.m

MATLAB function twoodes.m

Solutions to problems in the text

 


Tentative Lecture Outline

 

Week

Lecture

Topic

HW Problems and Reading:

DUE ON THE DAY

1/4

0

Introduction: Geological flows and a few concepts

 

 

1/11

1

Physical Principles: What are fluids? The continuum hypothesis and geological materials.

Heuberger et al., Density Fluctuations Under Confinement: When Is a fluid not a fluid?

Science, 292, 905-908, 2001.

 

 

 

Physical Principles: Systems, control volumes (CVs), conservation of mass and momentum;

 

Practice solving problems

Read: PF 1.1-1.2,1.5,1.6, 2.1-2.3

Read: CER 4 (as needed) and ch. 5

Note: We will not work with the energy equation here.

 

1/18

2

Physical Principles: More about CV formulation of conservation laws.

 

More practiceÉ. Some geological problems.

Read PF 2.4 ;

Read CER ch. 6

MFM: CVs=>Balance of momentum; art. 898-923; 936-948

Supplemental problems: Review 1

Probs: 2.3, 2.4, 2.8, 2.19

1/25

3

QUIZ 1. Continuum Mechanics Review

Read and outline supplemental notes on continuum mechanics; PF 1.3

Supplemental problems: Review 2

2/1

4

Lab: In-class group project: Measuring the slow spread of an oil layer, the shape of volcanic jets and the spread of volcanic clouds

 

2/8

 

Kinematics of fluids

Read: PF Ch. 3

 

2/15

5

QUIZ 2. PDEs of fluid flow

Navier Stokes Equations and Boundary Conditions

Probs: 1.7,1.16,1.18, 3.3

Supplemental problems: Kinematics (pdf)

R: PF Ch. 6

MFM: 160-167; 173-176

Probs: 3.5, 3.7, 3.19, 3.22 (ignore heat transfer!), 6.1, 6.2

2/29

6

Steady unidirectional flows. A Òclassical problem or twoÓ; Plate tectonics and a plume-fed asthenosphere

 

 

 

3/6

**TUESDAY**

7

Review for midterm: Problem-solving session

 

3/7

MIDTERM

MIDTERM EXAM AT 3 PM (mj away)

 

3/14

8

Unsteady unidirectional flows: Lava lake tectonics and other examples

 

Dimensional analysis and scaling: Working with what nature provides and making sense of the Navier Stokes equations.

 

R: PF Ch. 4; Middleton and Wilcock Ch. 3

Probs: PF 4.1, 4.2, 4.10

MFM: 520-562; DO LABS: 560&562!

 

3/21

 

9

Creeping gravity currents: Mantle plumes and very sticky lava flows.

R: 6.1-6.4

Project Proposal Due

3/28

10

QUIZ 3. Laminar and turbulent gravity currents on the ground. Scaling, stability, entrainment, mixing and drag.

 

R: Ch. 5.1-5.4, 9 ; 7.1-7.3

R: Simpson Chs 1, 11, 12 15

Supplemental problems: Analyzing your experimental gravity currents

MFM: 676-686, MFM: 710-719; 728-743

 

Journal Article Review Due

4/4

11

More about laminar and turbulent gravity currents on the ground.

 

Turbulent jets and gravity currents in the atmosphere and ocean: Explosive volcanic eruptions

 

Time-permitting (unlikely this year): Simply a cool problem-- the gravitational collapse of molecular clouds to form solar systems

MFM: 376-450; 676-686; 728-736; 832,856

 

4/11

12

Evening of Project Talks (Food Provided)

 

4/16

13

Take Home Final Exam Due