Interfacial instabilities of immiscible non-Newtonian radial displacements in porous media

2019 ◽  
Vol 31 (4) ◽  
pp. 043103 ◽  
Author(s):  
Y. H. Lee ◽  
J. Azaiez ◽  
I. D. Gates
2017 ◽  
Vol 819 ◽  
pp. 713-729 ◽  
Author(s):  
T. F. Lins ◽  
J. Azaiez

Interfacial instabilities of immiscible radial displacements in homogeneous porous media are analysed in the case of sinusoidal injection flows. The analysis is carried out through numerical simulations based on the immersed interface and level set methods. Investigations of the effects of the period of the sinusoidal injection flows revealed a novel resonance effect where, for a critical period, the number of fingers as well as their structures are considerably changed. The resonance in the flow development is clearly identified through the abrupt changes in the Fourier spectrum of the interface as well as quantitative characteristics of the flow in the form of the minimum and maximum radii of the interface. For the range of parameters examined in this study that correspond to instabilities dominated by viscous forces, the resonance period was found to correlate with a characteristic time of the flow and the fluids mobility ratio. This new physical phenomenon offers new perspectives for using the flow instability to determine important physical properties such as the viscosity and the surface tension of fluids.


1977 ◽  
Author(s):  
T.P. Castor ◽  
W.H. Somerton

2018 ◽  
Vol 115 (19) ◽  
pp. 4833-4838 ◽  
Author(s):  
Harris Sajjad Rabbani ◽  
Dani Or ◽  
Ying Liu ◽  
Ching-Yao Lai ◽  
Nancy B. Lu ◽  
...  

Finger-like protrusions that form along fluid−fluid displacement fronts in porous media are often excited by hydrodynamic instability when low-viscosity fluids displace high-viscosity resident fluids. Such interfacial instabilities are undesirable in many natural and engineered displacement processes. We report a phenomenon whereby gradual and monotonic variation of pore sizes along the front path suppresses viscous fingering during immiscible displacement, that seemingly contradicts conventional expectation of enhanced instability with pore size variability. Experiments and pore-scale numerical simulations were combined with an analytical model for the characteristics of displacement front morphology as a function of the pore size gradient. Our results suggest that the gradual reduction of pore sizes act to restrain viscous fingering for a predictable range of flow conditions (as anticipated by gradient percolation theory). The study provides insights into ways for suppressing unwanted interfacial instabilities in porous media, and provides design principles for new engineered porous media such as exchange columns, fabric, paper, and membranes with respect to their desired immiscible displacement behavior.


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