Large scale water movements in lakes

Hutter, Kolumban; Salvadè, G.; Spinedi, C.; Zamboni, F.; Bäuerle, Erich

doi:10.1007/bf00877057

Cited by 18 publications

(10 citation statements)

References 18 publications

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“…According to the model, the two oscillation modes have very similar periods. Mode 4 should, however, correspond to the second resonant mode of the thermocline, and it is nearly coincident with the value calculated by Hutter [27] and Hutter et al [28]; mode 5 should correspond to the third resonant mode of the chemocline. In mode 4, the model predicts a period value of about 11.4 h. The spectral analysis of the observations shows a distinct 12-h peak which could be the first higher harmonic response of the 24-h resonance: because of its large amplitude, this wave should be non-linear (see [23]).…”

Section: Modes 4 Andmentioning

confidence: 62%

Higher-Order Baroclinicity (I): Two Fluid Layers with Diffuse Interface – Three Fluid Layers with Sharp Interfaces

2011

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Section: Modes 4 Andmentioning

confidence: 62%

Higher-Order Baroclinicity (I): Two Fluid Layers with Diffuse Interface – Three Fluid Layers with Sharp Interfaces

2011

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“…Energy is supplied to lakes by wind: it drives the surface water and generates internal waves in the form of long-periodic basin-scale standing waves (Mortimer, 1952;Farmer, 1978;Hutter, 1986Hutter, , 1991. This implies that the internal wave energy in lakes is concentrated in a low-frequency band.…”

Section: Discussionmentioning

confidence: 99%

Numerical modelling of disintegration of basin-scale internal waves in a tank filled with stratified water

Stashchuk

Vlasenko²,

Hutter³

2005

Nonlin. Processes Geophys.

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Abstract. We present the results of numerical experiments performed with the use of a fully non-linear non-hydrostatic numerical model to study the baroclinic response of a long narrow tank filled with stratified water to an initially tilted interface. Upon release, the system starts to oscillate with an eigen frequency corresponding to basin-scale baroclinic gravitational seiches. Field observations suggest that the disintegration of basin-scale internal waves into packets of solitary waves, shear instabilities, billows and spots of mixed water are important mechanisms for the transfer of energy within stratified lakes. Laboratory experiments performed by D. A. Horn, J. Imberger and G. N. Ivey (JFM, 2001) reproduced several regimes, which include damped linear waves and solitary waves. The generation of billows and shear instabilities induced by the basin-scale wave was, however, not sufficiently studied.The developed numerical model computes a variety of flows, which were not observed with the experimental set-up. In particular, the model results showed that under conditions of low dissipation, the regimes of billows and supercritical flows may transform into a solitary wave regime. The obtained results can help in the interpretation of numerous observations of mixing processes in real lakes.

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“…Depending on the size and latitude of the lake, the spatiotemporal structure of gravity waves may or may not be affected by the local Coriolis acceleration caused by the Earth's rotation. The effect of Coriolis on the basin-scale gravity wave dynamics can be quantified by the Burger number,  ≡ R ∕R [2], defined as the ratio of the Rossby radius of deformation, R = c ∕f , to the relevant horizontal length-scale of the waterbody, R (for instance, half the width of the basin or half the longest fetch length) [2,27,37], where c is the longwave celerity and f is the inertial frequency. Hence, as  → 0 , the background rotation becomes strongly dominant in the flow dynamics.…”

Section: Introductionmentioning

confidence: 99%

Evolution and decay of gravity wavefields in weak-rotating environments: a laboratory study

2018

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Gravity waves are prominent physical features that play a fundamental role in transport processes of stratified aquatic ecosystems. In a two-layer stratified basin, the equations of motion for the first vertical mode are equivalent to the linearised shallow water equations for a homogeneous fluid. We adopted this framework to examine the spatiotemporal structure of gravity wavefields weakly affected by the background rotation of a single-layer system of equivalent thickness h , via laboratory experiments performed in a cylindrical basin mounted on a turntable. The wavefield was generated by the release of a diametral linear tilt of the air-water interface, , inducing a basin-scale perturbation that evolved in response to the horizontal pressure gradient and the rotation-induced acceleration. The basin-scale wave response was controlled by an initial perturbation parameter,  * = 0 ∕h , where 0 was the initial displacement of the air-water interface, and by the strength of the background rotation controlled by the Burger number, . We set the experiments to explore a transitional regime from moderate-to weak-rotational environments, 0.65 ≤  ≤ 2 , for a wide range of initial perturbations, 0.05 ≤  * ≤ 1.0. The evolution of was registered over a diametral plane by recording a laser-induced optical fluorescence sheet and using a capacitive sensor located near the lateral boundary. The evolution of the gravity wavefields showed substantial variability as a function of the rotational regimes and the radial position. The results demonstrate that the strength of rotation and nonlinearities control the bulk decay rate of the basin-scale gravity waves. The ratio between the experimentally estimated damping timescale, T d , and the seiche period of the basin, T g , has a median value of T d ∕T g ≈ 11 , a maximum value of T d ∕T g ≈ 10 3 and a minimum value of T d ∕T g ≈ 5. The results of this study are significant for the understanding the dynamics of gravity waves in waterbodies weakly affected by Coriolis acceleration, such as mid-to small-size lakes.

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Large scale water movements in lakes

Cited by 18 publications

References 18 publications

Higher-Order Baroclinicity (I): Two Fluid Layers with Diffuse Interface – Three Fluid Layers with Sharp Interfaces

Higher-Order Baroclinicity (I): Two Fluid Layers with Diffuse Interface – Three Fluid Layers with Sharp Interfaces

Numerical modelling of disintegration of basin-scale internal waves in a tank filled with stratified water

Evolution and decay of gravity wavefields in weak-rotating environments: a laboratory study

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