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Mathematical Structure of the Singularities at the Transitions Between Steady States in Hydrodynamic Systems PDF

286 Pages·1983·3.063 MB·English
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Preview Mathematical Structure of the Singularities at the Transitions Between Steady States in Hydrodynamic Systems

Lecture Notes in Physics Edited by H. Araki, Kyoto, J. Ehlers, MDnchen, K. Hepp, Ziirich R. Kippenhahn, MOnchen, H. A. Weidenmiiller, Heidelberg and J. Zittartz, Kijln 185 Hampton N. Shirer Robert Wells Mathematical Structure of the Singularities at the Transitions Between Steady States in Hydrodynamk Systems S pri nger-Verlag Berlin Heidelberg New York Tokyo 1983 Authors Hampton N. Shirer Department of Meteorology The Pennsylvania State University University Park, PA 16802, USA Robert Wells Department of Mathematics The Pennsylvania State University University Park, PA 16802, USA AMS Subject Classifications (1980): 58C 27, 58C 28, 76 E30 ISBN 3-540-l 2333-4 Springer-Verlag Berlin Heidelberg New York Tokyo ISBN O-387-1 2333-4 Springer-Verlag New York Heidelberg Berlin Tokyo This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under 5 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to “Verwettungsgesellschaft Wort”, Munich. 0 by Springer-Verlag Berlin Heidelberg 1983 Printed in Germany Printing and binding: Beltz Offsetdruck, HemsbachlBergstr. 2153/3140-543210 Dedicated to our wives, Becky Shirer and Valerie Wells, without whose encouragement this monograph would not have been completed. PREFACE Since its introduction by Rene Thom, catastrophe theory has been a potentially valuable instrument for discovering the nature of transitional behavior in physical systems. In the excitement generated by his new view of the world, a central technical obstacle was considerably underrated, ~-Ith the result that now an army of critics has replaced the original multitude of proponents. The great promise of catastrophe theory is that with it, out of a vast number of influences on an evolving system, we may select a small number through which the rest will act to control the transitional behavior of that system. From this situation, we may obtain the classical, canonical pictures of surfaces of steady solutions and sets of bifurcation points, parameterlzed by a few numbers quantifying the few controlling influences. However, to apply catastrophe theory as it was originally formulated, we must have a potential or Lyapunov function for our evolutionary system. This requirement is the central technical obstacle to the rigorous application of catastrophe theory, the obstacle which was not overcome adequately in the early applications. Unfortunately it is in general, extremely difficult, if not impossible, to show that such a function exists, let alone to produce it. Consequently, most attempts at realization of the full promise of the theory cannot even get started. Yet the canonical surfaces and singularity sets of catastrophe theory have appeared, independently of that theory, in the description of the behavior of a wide variety of physical systems. This fact is closely related to a singularity theory originated by John Mather during his work to establish the mathematical foundations of catastrophe theory. Besides enjoying the inestimable advantage of being mathematically rigorous, this generalization completely by-passes the central technical difficulty of catastrophe theory: Mather's Theory requires no Lyapunov function, and yet it can do everything that catastrophe theory, in the presence of a Lyapunov function, can do. In fact, now the appearance of the canonical surfaces and singularity sets in systems not regulated by a Lyapunov function is explained completely by Mather's Theory. Unfortunately, Mather's Theory also includes an obstacle; it is as inaccessible to an applied physicist as anything in mathematics can be. Accordingly, to fill the gap between theory and utillzatlon~ in this monograph we first describe Mather's Theory operationally using examples instead of proofs, and then we develop a procedure for Its application to physical problems whose dynamics are governed by systems of ordinary differential equations. We demonstrate the utility of our procedure by applying it to three different hydrodynamic systems. We show first how to identify the crucial parameters in the equations and then how to associate them with the corresponding physical effects. Consequently, by finding these parameters, we obtain systems that no longer must be unrealistically ideal because certain of their crucial parameters need not remain identically zero. The strength of our Vl application of singularity theory is that we obtain a theoretical model whose solutions are directly comparable with experimental observations. An apparent defect of Mather's Theory is that it does not, as it stands, describe the stability characteristics of the stationary solutions of a dynamical system. In particular, it does not respect Hopf bifurcations. However, it is readily extendable to a theory which does describe the stability characteristics, and we describe this extension in the final chapter. We are deeply grateful to Professor John A. Dutton for the encouragement and advice freely given us during the lengthy evolution of this monograph from a jumble of ideas to six chapters of organized material. We also thank him for his many constructive criticisms of earlier versions of this manuscript that allowed better presentation of its contents. We greatly appreciate the interest and useful comments given us by our colleagues. In particular, we thank Mr. David A. Yost for his help in unraveling the subtleties of horizontally and vertically heated convection, Dr. Kenneth E. Mitchell for his advice concerning quasi-geostrophic flow in a channel, and Dr. Peter Kloeden for directing us to the appropriate low-order model of rotating convection. Finally, we are indebted to Mrs. Lori Weaver for her patient and meticulous efforts in typing the nearly unending stream of revisions of this manuscript, and to Mr. Victor King for his excellent drafting of the figures. The research reported here was sponsored by the National Science Foundation through grants ATM 78-02699, ATM 79-08354, and ATM 81-13223 and by the National Aeronautic and Space Administration through grants NSG-5347 and NAS8-33794. May 1983 Hampton N. Shirer Robert Wells TABLE OF CONTENTS I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I.I Transitions in Hydrodynamics . . . . . . . . . . . . . . . . . . 1 1.2 Modeling Observed Transitions . . . . . . . . . . . . . . . . . . 3 2. INTRODUCTION TO CONTACT CATASTROPHE THEORY . . . . . . . . . . . . . . 7 2.1 The Stationary Phase Portrait . . . . . . . . . . . . . . . . . . 7 Example i. The cusp and hysteresis . . . . . . . . . . . . . . 8 2.2 The Definitions of Mather's Theory . . . . . . . . . . . . . . . 12 Example 2. A contact map to the cusp: embedding and hysteresis . . . . . . . . . . . . . . 14 Example 3. A contact map to the cusp: embedding and bifurcation . . . . . . . . . . . . . 14 Example 4. A contact map to the cusp: extension ....... 15 Example 5. A contact map to the cusp: transformation of coordinates . . . . . . . . . . . 17 Example 6. Destruction of information: loss of periodic solutions . . . . . . . . . . . . . 18 Example 7. Versal unfolding of f(x) = x . . . . . . . . . . . 20 Example 8. A versal unfolding of the Lorenz (1963) model: a preview . . . . . . . . . . . . . . . . . . . . . 21 2.3 Mather's Theorems . . . . . . . . . . . . . . . . . . . . . . . . 24 Example 9. The cusp and Mather's Theorem I . . . . . . . . . . 25 Example I0. A versal unfolding of the Lorenz model: Mather's Theorem II ...... . . . . . . . . . . 28 2.4 Altering Versal Unfoldings . . . . . . . . . . . . . . . . . . . 30 Example II. Codimension and the cusp . . . . . . . . . . . . . . 32 Example 12. Versal unfoldlngs of the Lorenz model: elementary alterations . . . . . . . . . . . . . . . 33 Example 13. Versal unfoldings of the Lorenz model: alterations . . . . . . . . . . . . . . . . . . . . 36 2.5 The Lyapunov-Schmidt Splitting Procedure . . . . . . . . . . . . 38 Example 14. A versal unfolding of the Lorenz model: splitting and reducing lemmas . . . . . . . . . . . 45 2.6 Vector Spaces and Contact Computations . . . . . . . . . . . . . 47 Example 15. Codimenslon: Propositions 2.2 and 2.3 ....... 48 Example 16. The dimension of ~(n)/~2(n): quotient spaces . . , 49 Example 17. Codimension of x3: versal unfoldings ....... 51 Example 18. Unfoldings of ± x k, k > 2: minimal versal forms in codimension 1 . . . . . . . . . . . . . . . 52 IIIV TABLE OF CONTENTS (Con't) Example 19. The hyperbolic umbillc: minimal versal unfoldings . . . . . . . . . . . . . 53 Example 20. The elliptic umbillc: minimal versal unfoldings . . . . . . . . . . . . . 56 2.7 Classification of Singularities . . . . . . . . . . . . . . . . . 57 Example 21. A versal unfolding of a nonpolynomial function: contact equivalence to a polynomial ........ 58 Table 2.1 Corank i unfoldings . . . . . . . . . . . . . . . . 61 Table 2.2 Corank 2 unfoldings . . . . . . . . . . . . . . . . 61 2.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3. RAYLEIGH-BENARD CONVECTION . . . . . . . . . . . . . . . . . . . . . . 67 3.1 Classification of the SingUlarity . . . . . . . . . . . . . . . . 69 3.2 Physical Interpretation of the Unfolding . . . . . . . . . . . . 73 4. QUASI-GEOSTROPHIC FLOW IN A CHANNEL . . . . . . . . . . . . . . . . . 82 4.1 Heating at the Middle Wavenumber Only . . . . . . . . . . . . . . 83 4.2 Singularities in the Vickroy and Dutton Model .......... 91 4.3 Butterfly Points in the Rossby Regime . . . . . . . . . . . . . . 94 5. ROTATING AXISYMMETRIC FLOW . . . . . . . . . . . . . . . . . . . . . . 114 5.1 The Butterfly Points . . . . . . . . . . . . . . . . . . . . . . 116 5.2 Unfolding about the Butterfly Point: The Hadley Problem .... 121 5.3 Unfolding about the Butterfly Point: The Rotating Raylelgh-Benard Problem . . . . . . . . . . . . . . . . . . . . . 123 5.4 Dynamic Similarity . . . . . . . . . . . . . . . . . . . . . . . 125 5.4.1 Horizontal heating . . . . . . . . . . . . . . . . . . . . 131 5.4.2 Tilting domain . . . . . . . . . . . . . . . . . . . . . . 135 5.4.3 Other candidates . . . . . . . . . . . . . . . . . . . . . 137 5.4.4 Final comments . . . . . . . . . . . . . . . . . . . . . . 144 6. STABILITY AND UNFOLDINGS . . . . . . . . . . . . . . . . . . . . . . . 145 6.1 Invarlant Sets of Matrices . . . . . . . . . . . . . . . . . . . 146 Example i. Some invariant subsets of M 2 . . . . . . . . . . . . 148 6.2 Smooth Submanifolds of R n . . . . . . . . . . . . . ....... 153 Example 2. The sphere: a 2-submanlfold of R 3 ......... 154 Example 3. The double cone: a subset which is not a submanifold of R 3 . . . . . . . . . . . . . . . . . 155 Example 4. The cone: a subset which is not a smooth submanifold of R 3 157 Example 5. Invarlant submanifolds . . . . . . . . . . . . . . . 159 Example 6. The orbit of a matrix . . . . . . . . . . . . . . . 159 Example 7. Some orbits in M 2 . . . . . . . . . . . . . . . . . 164 IX TABLE OF CONTENTS (Con't) 6.3 Transversality and Tangent Space . . . . . . . . . . . . . . . . 167 Example 8. Transversal curves and surfaces . . . . . . . . . . 167 Example 9. Transversality of two circles in the plane ..... 169 Example i0. The tangent space at the fold on a cusp surface . . . , . . , , . , . . , . . . . . , . . . 176 Example II. The tangent space of Orb(F) . . . . . . . . . . . . 177 Example 12. The spaces associated with transversallty of a map on the cusp surface . . . . . . . . . . . . . . 180 Example 13. Computational verification of transversallty of a map on the cusp surface . . . . . . . . . . . . 183 Example 14. Transversality of maps associated with the hyperbolic umbillc . . . . . . . . . . . . . . . . . 184 6.4 Versal Unfoldlngs and Contact Transformations of the First Order . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Example 15. An extended hyperbolic umbillc . . . . . . . . . . . 191 Example 16. First-order contact transformations of the extended hyperbolic umbillc . . . . . . . . . . . . 196 Example 17. First-order contact transformation of the hyperbolic umbillc . . . . . . . . . . . . . . . . . 196 6.5 Stability and First-Order Versal Unfoldings and Contact Transformations . . . . . . . . . . . . . . . , , . . ..... . 201 Example 18. The modified Lorenz system unfolded further .... 203 Example 19. The stability phase portrait of a flrst-order versal unfolding of the Lorenz system . . . . . . . 213 Example 20. The stability phase portrait of the original unfolding of the modified Lorenz system ...... 217 6.6 First-Order Mather Theory . . . . . . . . . . . . . . . . . . . . 223 Example 21. The flrst-order Versal unfolding of x n . . . . . . . 233 Example 22. First-Order Versal unfolding of a fold . . . . . . . 235 Example 23. The stability phase portrait of a general first-order versal unfolding of g(x) = x2, - Xl, x32T . . . . . . . . . . . . . . 247 6.7 Conclusion . , . . . . . . . . . . . . . . . ..... . . . . . 253 APPENDIX SUMMARY OF SPECTRAL MODELS . . . . . . . . . . . . . . . . . . . 256 A.I The Lorenz Model . . . . . . . . . . . . . . . . . . . . . . . . 256 Table A.I Dimensional Variables: Lorenz Model . . . . . . . . . 257 Table A.2 Nondlmensional Variables & Parameters: Lorenz Model . . . . . . . . . . . . . . . . . . . . . 258 TABLE OF CONTENTS (Con't) A.2 The vickroy and Dutton Model . . . . . . . . . . . . . . . . . . 259 Table A.3 Nondlmensional Variables & Parameters: Vickroy and Dutton Model . . . . . . . . . . . . . . . 261 A.3 The Charney and DeVore Model ................... 265 Table A.4 Dimensional Variables: Charney and DeVore Model . . . . . . . . . . . . . . . . . . . . . 265 Table A.5 Nondimenslonal Variables & Parameters: Charney and DeVore Model . . . . . . . . . . . . . . . 266 A.4 The Veronis Model . . . . . . . . . . . . . . . . . . . . . . . . 268 Table A.6 Dimensional Variables: Veronis Model ........ 269 Table A.7 Nondimensional Variables & Parameters: Veronis Model . . . . . . . . . . . . . . . . . . . . 270 Table A.8 Butterfly Points in the Veronis Model ........ 273 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 "There is an almost forgotten branch of mathematics, called catastrophe theory, which could make meteorology a really precise science." --from a conversation between the Venerable Parakarma and Mahnayake Thero in The Foundation of Paradise by Arthur C. Clarke, 1978.

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