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Talks and Poster Presentations (with Proceedings-Entry):

M. Müllner:
"Near-critical turbulent open-channel flow over wavy bottom";
Talk: 89th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), München, Germany; 2018-03-19 - 2018-03-23; in: "Proceedings in Applied Mathematics and Mechanics", PAMM (WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim), 18 (2018), ISSN: 1617-7061.



English abstract:
Steady two-dimensional turbulent free-surface flow in a channel with mild baseline slope is considered. The shape of the
channel bottom is assumed to be undular with a very small amplitude. Asymptotic expansions for large Reynolds numbers
and Froude numbers slightly above the critical value 1, respectively, give for the surface elevation a differential equation
of KdV-type, with the additional terms representing turbulent dissipation and forcing due to the wavy bottom, respectively.
No turbulence modelling is required. This asymptotic approach was used in [1] to describe stationary solitary waves in a
channel with plain bottom and small variations in the bottom friction coefficient. It was shown recently [2, 3] that there exist
stationary single-wave solutions of a different kind that are characterized by smaller wave amplitudes. In [4], both kinds of
single stationary waves above single obstacles (bumps, ramps) are investigated theoretically and experimentally.
In this paper, stationary space-periodic surface waves for channel bottoms with undular shape are studied. First, a oneparametric
family of exact solutions for particular bottom shapes is derived. Remarkably, these particular solutions exist
only in a narrow parameter range. The solutions are reproduced with a numerical solver to verify that the solver gives correct
results. Secondly, a different type of asymptotic expansion is performed in order to describe solutions characterized by smaller
wave amplitudes. The resulting linear differential equation is solved numerically. Both solutions are briefly discussed.


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1002/pamm.201800272



Related Projects:
Project Head Wilhelm Schneider:
AIC Androsch International Management Consulting GmbH Forschung auf dem Fachgebiet Strömungsmechanik und Thermodynamik


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