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**Secondary generation of breaking internal waves in confined basins by gravity currents.**
*(English)*
Zbl 07347173

Summary: In confined stratified basins, wind forcing is an important mechanism responsible for the onset and generation of internal waves and seiches. Previous observations have also found that gravity currents in stratified environments can also initiate internal waves. We conducted a series of laboratory experiments to investigate the generation of internal motions due to such dense gravity currents on an incline entering a two-layer stratification, focusing in particular on the interaction between the onset of internal motions and topography and diapycnal mixing due to breaking internal waves. The baroclinic response of the ambient stratification to the gravity current is found to be analogous to a system forced by a surface wind stress, and the response as characterized by a Wedderburn-like number was found to be linearly proportional to the initial gravity current Richardson number. The generated internal motions are characterized as having a low-frequency internal surge and higher-frequency progressive internal waves. The overall mixing efficiency of the breaking internal wave was calculated and found to be low compared with similar previous studies.

### MSC:

76B55 | Internal waves for incompressible inviscid fluids |

76B70 | Stratification effects in inviscid fluids |

76-05 | Experimental work for problems pertaining to fluid mechanics |

### Keywords:

two-layer stratification; diapycnal mixing; baroclinic effect; wave breaking; low-frequency internal surge; experimental verification### Software:

jLab
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\textit{Y. Tanimoto} et al., J. Fluid Mech. 917, Paper No. A49, 27 p. (2021; Zbl 07347173)

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### References:

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