Direct Numerical Simulation of Kelvin-Helmholtz Instability and Interfacial Stress Tensor Modeling
The development of the Kelvin-Helmholtz instability for the stratified, large density ratio flow in rectangular channels is investigated and the models for the interfacial shear stress and interfacial pressure of small-amplitude waves based on the linear analysis are derived. A reduced geometrical model is adopted, and the 2D and 3D simulation results are compared with previous experiments. It is shown that the generation and development of the Kelvin-Helmholtz instability are successfully captured. The numerical simulation tends to underestimate the wave length. The onset of the instability for the experiment is earlier than that in the 2D simulation, while it is later when compared to the 3D simulation. The models of the interfacial shear stress and interfacial pressure are obtained for waves that have wave length comparable to the channel height. The derived theoretical results are compared with numerical simulations of a single solid wave and interfacial waves between immiscible fluids. It is presented that the simplified theoretical results are in good agreement with the simulation results.
Lopez-De-Bertodano, Purdue University.
Nuclear engineering|Mechanical engineering
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