scholarly journals Mesoscale Eddy–Internal Wave Coupling. Part II: Energetics and Results from PolyMode

2010 ◽  
Vol 40 (4) ◽  
pp. 789-801 ◽  
Author(s):  
Kurt L. Polzin
Keyword(s):  
Transfer Coefficient ◽  
Internal Wave ◽  
Energy Budget ◽  
Wave Energy ◽  
Horizontal Transfer ◽  
Mesoscale Eddy ◽  
Wave Coupling ◽  
Vertical Transfer ◽  
Eddy Field

Abstract The issue of internal wave–mesoscale eddy interactions is revisited. Previous observational work identified the mesoscale eddy field as a possible source of internal wave energy. Characterization of the coupling as a viscous process provides a smaller horizontal transfer coefficient than previously obtained, with vh ≅ 50 m2 s−1 in contrast to νh ≅ 200–400 m2 s−1, and a vertical transfer coefficient bounded away from zero, with νυ + ( f 2/N 2)Kh ≅ 2.5 ± 0.3 × 10−3 m2 s−1 in contrast to νυ + ( f 2/N 2)Kh = 0 ± 2 × 10−2 m2 s−1. Current meter data from the Local Dynamics Experiment of the PolyMode field program indicate mesoscale eddy–internal wave coupling through horizontal interactions (i) is a significant sink of eddy energy and (ii) plays an O(1) role in the energy budget of the internal wave field.

scholarly journals Spontaneous Surface Generation and Interior Amplification of Internal Waves in a Regional-Scale Ocean Model

2017 ◽  
Vol 47 (4) ◽  
pp. 811-826 ◽  
Author(s):  
Callum J. Shakespeare ◽  
Andrew McC. Hogg
Keyword(s):  
Internal Wave ◽  
Wave Field ◽  
Energy Budget ◽  
Wave Energy ◽  
Channel Model ◽  
Regional Scale ◽  
Wave Generation ◽  
Ocean Model ◽  
Surface Generation ◽  
Spontaneous Generation

AbstractRecent theories, models, and observations have suggested the presence of significant spontaneous internal wave generation at density fronts near the ocean surface. Spontaneous generation is the emission of waves by unbalanced, large Rossby number flows in the absence of direct forcing. Here, spontaneous generation is investigated in a zonally reentrant channel model using parameter values typical of the Southern Ocean. The model is carefully equilibrated to obtain a steady-state wave field for which a closed energy budget is formulated. There are two main results: First, waves are spontaneously generated at sharp fronts in the top 50 m of the model. The magnitude of the energy flux to the wave field at these fronts is comparable to that from other mechanisms of wave generation. Second, the surface-generated wave field is amplified in the model interior through interaction with horizontal density gradients within the main zonal current. The magnitude of the mean-to-wave conversion in the model interior is comparable to recent observational estimates and is the dominant source of wave energy in the model, exceeding the initial spontaneous generation. This second result suggests that internal amplification of the wave field may contribute to the ocean’s internal wave energy budget at a rate commensurate with known generation mechanisms.

Influence of the Distortion of Vertical Wavenumber Spectra on Estimates of Turbulent Dissipation using the Finescale Parameterization: Eikonal Calculations

2021 ◽  
Author(s):  
ANNE TAKAHASHI ◽  
TOSHIYUKI HIBIYA ◽  
ALBERTO C. NAVEIRA GARABATO
Keyword(s):  
Internal Wave ◽  
Wave Energy ◽  
Mesoscale Eddy ◽  
Wave Interaction ◽  
Interaction Theory ◽  
Turbulent Dissipation ◽  
Energy Cascades ◽  
Circumpolar Current ◽  
Noise Contamination ◽  
The Antarctic

AbstractThe finescale parameterization, formulated on the basis of a weak nonlinear wave–wave interaction theory, is widely used to estimate the turbulent dissipation rate, ε. However, this parameterization has previously been found to overestimate ε in the Antarctic Circumpolar Current (ACC) region. One possible reason for this overestimation is that vertical wavenumber spectra of internal wave energy are distorted from the canonical Garrett-Munk spectrum and have a spectral “hump” at low vertical wavenumbers. Such distorted vertical wavenumber spectra were also observed in other mesoscale eddy-rich regions. In this study, using eikonal simulations, in which internal wave energy cascades are evaluated in the frequency-wavenumber space, we examine how the distortion of vertical wavenumber spectra impacts on the accuracy of the finescale parameterization. It is shown that the finescale parameterization overestimates ε for distorted spectra with a low-vertical-wavenumber hump because it incorrectly takes into account the breaking of these low-vertical-wavenumber internal waves. This issue is exacerbated by estimating internal wave energy spectral levels from the low-wavenumber band rather than from the high-wavenumber band, which is often contaminated by noise in observations. Thus, in order to accurately estimate the distribution of ε in eddy-rich regions like the ACC, high-vertical-wavenumber spectral information free from noise contamination is indispensable.

scholarly journals Energy budget in internal wave attractor experiments

2019 ◽  
Vol 880 ◽  
pp. 743-763 ◽  
Author(s):  
Géraldine Davis ◽  
Thierry Dauxois ◽  
Timothée Jamin ◽  
Sylvain Joubaud
Keyword(s):  
Velocity Field ◽  
Internal Wave ◽  
Boundary Layers ◽  
Energy Budget ◽  
Dissipation Rate ◽  
Theoretical Expression ◽  
Two Dimensional ◽  
Energy Sink ◽  
Set Up ◽  
Different Sources

The current paper presents an experimental study of the energy budget of a two-dimensional internal wave attractor in a trapezoidal domain filled with uniformly stratified fluid. The injected energy flux and the dissipation rate are simultaneously measured from a two-dimensional, two-component, experimental velocity field. The pressure perturbation field needed to quantify the injected energy is determined from the linear inviscid theory. The dissipation rate in the bulk of the domain is directly computed from the measurements, while the energy sink occurring in the boundary layers is estimated using the theoretical expression for the velocity field in the boundary layers, derived recently by Beckebanze et al. (J. Fluid Mech., vol. 841, 2018, pp. 614–635). In the linear regime, we show that the energy budget is closed, in the steady state and also in the transient regime, by taking into account the bulk dissipation and, more importantly, the dissipation in the boundary layers, without any adjustable parameters. The dependence of the different sources on the thickness of the experimental set-up is also discussed. In the nonlinear regime, the analysis is extended by estimating the dissipation due to the secondary waves generated by triadic resonant instabilities, showing the importance of the energy transfer from large scales to small scales. The method tested here on internal wave attractors can be generalized straightforwardly to any quasi-two-dimensional stratified flow.

Cascade of Internal Wave Energy Catalyzed by Eddy‐Topography Interactions in the Deep South China Sea

2020 ◽  
Vol 47 (4) ◽  
Author(s):  
Qianwen Hu ◽  
Xiaodong Huang ◽  
Zhiwei Zhang ◽  
Xiaojiang Zhang ◽  
Xing Xu ◽  
...  
Keyword(s):  
South China Sea ◽  
Internal Wave ◽  
South China ◽  
Wave Energy ◽  
Deep South ◽  
China Sea

scholarly journals Assessment of Innovative Activity of Ukrainian Enterprises in the Field of Technology Transfer

2021 ◽  
Vol 2 (48) ◽  
pp. 134-142
Author(s):  
M. V. Korneyev ◽  
◽  
A. I. Zhydyk ◽  
Keyword(s):  
Technology Transfer ◽  
Horizontal Transfer ◽  
Innovative Activity ◽  
Innovation Activity ◽  
Investment Climate ◽  
Vertical Transfer ◽  
Industrial Enterprises ◽  
Technology Platforms ◽  
Research Organizations ◽  
Enterprise Level

The article aims at clarifying the classification features of the forms and directions of technology transfer, and analyzing empirical data on technology transfer operations in Ukraine. The effectiveness, efficiency and immediacy of technology transfer depend on the choice of its rational forms and directions of technology transfer. The combined form of transfer is considered to be most promising, as it encompasses the advantages of both the vertical and horizontal transfer forms based on the open innovation business model. Ukraine has prerequisites for the implementation of this form of technology transfer, but it is necessary to increase the innovative activity of industrial enterprises and research organizations, and to increase funding for innovation. In the future the authors plan to suggest an organizational and economic mechanism to increase innovation activity at the enterprise level. In 2007-2019 research and development at industrial enterprises (R&D) accounted for about 15% in the total cost of innovation, in average. The lowest share of R&D in total expenditures on innovation was observed in 2011 (7.5%), and the highest share was observed in 2018, comprising 26.3%. The share of costs for vertical transfer is 69.6-89.5%, which is much higher than that for horizontal transfer, which is 10.5-30.4%. The main reason for the decrease in the level of technology transfer at Ukrainian enterprises is the limited funding from the state and the negative investment climate in the country. The share of non-commercial transfers has been lower than 1% since 2012. Combined transfer based on digital technology platforms is virtually absent.

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