From svfleet at uw.edu Mon Mar 25 11:42:27 2024 From: svfleet at uw.edu (Samuel Van Fleet) Date: Mon Mar 25 11:48:07 2024 Subject: [Amath-seminars] Boeing Colloquium Thursday March 28 Message-ID: Hello Everyone, This Thursday, March 28 Dr. Lisa Fauci from Tulane University will be giving a talk as a part of the Boeing Distinguished Colloquium Series. The talk will take place in Smith Hall, room 205 from 4:00pm to 5:00pm. The title and abstract of the talk can be found on the Applied Mathematics website here . Best, Sam Van Fleet -- Sam Van Fleet (he/him/his) Acting Instructor of Applied Mathematics Department of Applied Mathematics University of Washington Seattle WA 98195 -------------- next part -------------- An HTML attachment was scrubbed... URL: From amath-seminars at u.washington.edu Fri Mar 29 16:07:28 2024 From: amath-seminars at u.washington.edu (Anastassiya Semenova via Amath-seminars) Date: Fri Mar 29 16:09:39 2024 Subject: [Amath-seminars] Next Boeing Colloquium Speaker: Professor Diane Henderson from Pennsylvania State University (on Thursday, April 4) Message-ID: Dear All, Our next Boeing Colloquium will feature *Professor Diane Henderson* from Pennsylvania State University. The talk will take place in *Smith Hall, Room 205, from 4:00pm to 5:00pm on Thursday, April 4th*. Please let me know if you have any questions. Here is the title and abstract for the talk: *Title:* Understanding nonlinear surface water waves on deep water *Abstract:* Oceanographers in the 60s conducted an ambitious experiment (1) in which they tracked waves that were generated by large storms near New Zealand across the Pacific Ocean until they hit the beaches at Alaska. Paradoxically, at about the same time, mathematicians in the Soviet Union, the U.S., and England (2) independently developed mathematical models that predicted such waves to be unstable, meaning that they could not survive to be tracked all the way across the Pacific. In the 70s experimentalists (3) conducted laboratory experiments on these types of waves. They generated waves with a given frequency that propagated down a wavetank, but at the end of the wavetank, the waves had a slightly lower frequency. The mathematical model did not explain this observation. In this talk, we consider these observations and our experiments on modulated wavetrains within the framework of the mathematical models: the scalar and vector nonlinear Schroedinger equations with and without dissipation and/or higher order terms. We examine the data within the context of conserved quantities of these equations to determine when the models are likely to be valid or not. We present recent results from our quest, motivated by recent stability analyses of Stokes waves (4), to observe subharmonic instabilities of waves in deep, finite and shallow water. *References:* (1) Snodgrass, F. E., G. W. Groves, K. F. Hasselmann, G. R. Miller, W. H. Munk, and W. H. Powers (1966), Propagation of ocean swell across the Pacific, Philos. Trans. R. Soc. London A, 259, 431?497. (2a) Benney, D. J. & Newell, A. C. 1967 The propagation of nonlinear wave envelopes. Stud. Appl.Maths 46, 133?139. (2b) Lighthill, M. J. 1965 Contribution to the theory of waves in nonlinear dispersive systems. J. Inst. Math. Applics. 1, 269?306. (2c) Benjamin, T. B. & Feir, J. E. 1967 The disintegration of wavetrains in deep water. Part 1. J. Fluid Mech. 27, 417?430. (2d) Ostrovsky, L. A. 1967 Propagation of wave packets and space-time self-focussing in a nonlinear medium. Sov. Phys. J. Exp. Theor. Phys. 24, 797?800. (2e) Whitham, G. B. 1967 Nonlinear dispersion of water waves. J. Fluid Mech. 27, 399?412. (2f) Zakharov, V. E. 1967 Instability of self-focusing of light. Sov. Phys. J. Exp. Theor. Phys. 24, 455?459. (2g) Zakharov, V. E. 1968 Stability of periodic waves of finite amplitude on the surface of a deep fluid. J. Appl. Mech. Tech. Phys. 2, 190?194. (3a) Lake, B. M. & Yuen, H. C. 1977 A note on some water-wave experiments and the comparison ofdata with theory. J. Fluid Mech. 83, 75?81. (3b) Lake, B. M., Yuen, H. C., Rungaldier, H. & Ferguson, W. E. 1977 Nonlinear deep-water waves:theory and experiment. Part 2. Evolution of a continuous wave train. J. Fluid Mech. 83, 49?74. (4) B. Deconinck, S. A. Dyachenko, P. M. Lushnikov, A. Semenova, The instability of near-extreme Stokes waves, Proceedings of the National Academy of Sciences, Best Regards, Anastassiya Semenova Department of Applied Mathematics University of Washington -------------- next part -------------- An HTML attachment was scrubbed... URL: