<p>Recently, there has been interest in stabilizing mechanisms for the classical viscous fingering instabilities in Hele-Shaw cells. Here, we critically review the stability criterion and derive it more generally, going beyond the single-finger criterion and analytically deriving critical slowing-down times in the slow-flow regime. We rederive the stability analysis for the linear opening scenario, obtaining a multiple-finger instability phase diagram, where we determine that the linear opening profile does not increase the stability range in the (<i>U</i>,&#xa0;<i>W</i>) space unless velocity corrections are considered. Furthermore, we found a crossing in the stability ranges at critical values of <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\((U_c,W_c)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">(</mo> <msub> <mi>U</mi> <mi>c</mi> </msub> <mo>,</mo> <msub> <mi>W</mi> <mi>c</mi> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>, indicating an enlarged stability for Hele-Shaw cells with a linear profile, only for wide cells and low flow speeds. We further analyze other opening profiles amenable to analytical treatment, including the power-law and exponential profiles.</p>

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Two-Phase Displacement Instabilities in Variable-Gap Hele-Shaw Cells

  • Diego Orozco,
  • Dalena León-FonFay,
  • Camilo Zamora-Ledezma,
  • Ernesto Medina

摘要

Recently, there has been interest in stabilizing mechanisms for the classical viscous fingering instabilities in Hele-Shaw cells. Here, we critically review the stability criterion and derive it more generally, going beyond the single-finger criterion and analytically deriving critical slowing-down times in the slow-flow regime. We rederive the stability analysis for the linear opening scenario, obtaining a multiple-finger instability phase diagram, where we determine that the linear opening profile does not increase the stability range in the (UW) space unless velocity corrections are considered. Furthermore, we found a crossing in the stability ranges at critical values of \((U_c,W_c)\) ( U c , W c ) , indicating an enlarged stability for Hele-Shaw cells with a linear profile, only for wide cells and low flow speeds. We further analyze other opening profiles amenable to analytical treatment, including the power-law and exponential profiles.