Journal
JOURNAL OF FLUID MECHANICS
Volume 780, Issue -, Pages 388-406Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2015.481
Keywords
absolute/convective instability; fingering instability; porous media
Categories
Funding
- National Board for Higher Mathematics, Government of India
Ask authors/readers for more resources
The influence of viscosity contrast on buoyantly unstable miscible fluids in a porous medium is investigated through a linear stability analysis (LSA) as well as direct numerical simulations (DNS). The linear stability method implemented in this paper is based on an initial value approach, which helps to capture the onset of instability more accurately than the quasi-steady-state analysis. In the absence of displacement, we show that viscosity contrast delays the onset of instability in buoyantly unstable miscible fluids. Further, it is observed that by suitably choosing the viscosity contrast and injection velocity a gravitationally unstable miscible interface can be stabilized completely. Through LSA we draw a phase diagram, which shows three distinct stability regions in a parameter space spanned by the displacement velocity and the viscosity contrast. DNS are performed corresponding to parameters from each regime and the results obtained are in accordance with the linear stability results. Moreover, the conversion from one dimensionless formulation to another and its importance when comparing the different type of flow problem associated with each dimensionless formulation are discussed. We also calculate epsilon-pseudo-spectra of the time dependent linearized operator to investigate the response to external excitation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available