On the sub-harmonic instabilities of three-dimensional interfacial gravity–capillary waves in infinite depths

In order to analyze the stability of gravity–capillary short-crested waves propagating at the interface of two fluids of infinite depths, a numerical procedure has been developed using a collocation method. The three-dimensional wave is generated by an oblique reflection of a uniform wave train arri...

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Bibliographic Details
Main Authors: Chikhi, Sara, Debiane, Mohammed, Allalou, Nabil
Format: Article
Language:English
Published: Académie des sciences 2022-05-01
Series:Comptes Rendus. Mécanique
Subjects:
Online Access:https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.111/
Description
Summary:In order to analyze the stability of gravity–capillary short-crested waves propagating at the interface of two fluids of infinite depths, a numerical procedure has been developed using a collocation method. The three-dimensional wave is generated by an oblique reflection of a uniform wave train arriving at a vertical wall at some angle of incidence ${\theta }$ measured from the perpendicular to the wall. Fixing the reflection at angle $\theta =45\text{°}$, and wave steepness at $h=0.25$, we studied the influence of the density ratio $\mu $ and the inverse Bond number $\delta $ on the unstable area and the growth rate. It was observed that the unstable regions and the maximum growth rate decrease when $\mu $ and $\delta $ increase. Also, we found that the dominant instability belongs to the Class Ib as in the case of free-surface gravity waves in deep water.
ISSN:1873-7234