Simulation of Surface Instability at the Interface of Two Fluids

Year 2017, Volume: 13 Issue: 2, 365 - 377, 30.06.2017

Nurdan Yıldırım , *, Jean-marie Buchlin Carlo Benocci

https://doi.org/10.18466/cbayarfbe.319878

Abstract

In this theoretical and numerical study, the physical
mechanisms leading to the production of surface waves generated at the
interface of two fluids (liquid/gas or liquid/liquid) are investigated.
Particular attention is devoted to the Kelvin-Helmholtz (KH) type instability,
which appears in the area of high shear located at the fluid-fluid interface.
The subsequent disturbances in velocity and pressure associated with the wave
motion are assumed to be 2D and sufficiently small to justify the linearization
of the equations of the motion. The Navier-Stokes (NS), Orr-Sommerfeld (OS) and
KH equations are the primary ones used to investigate of surface instability. During
the study, the main characteristics of a surface instability such as
wavelength, wave number, frequency, amplitude, wave speed and growth rate are
investigated according to fluid viscosity. The effect of gravity is
investigated by 2D simulations without these external forces or with them in
one of the following configurations:

Keywords

Surface wave, surface instability, viscosity, gravity, two-layer fluid flow

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