Abstract—

The Rayleigh–Taylor instability and the initial stage of density-driven convection in a porous medium is simulated numerically in reference to geologic problems. A two-layer fluid system in which the lower layer is formed by pure water and the upper layer by an aqueous solution of salts is considered. The upper layer is more dense and viscous. The determination of the characteristic time of the onset of convection in the numerical solution is discussed. The parameters which depend on and do not depend of the initial density fluctuations are revealed. The effect of the viscosity contrast on the onset and development of convection flow and mass transfer is analyzed. The quantitative discrepancies related to neglecting the viscosity contrast in geologic fluids are estimated.

中文翻译：

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多孔介质中瑞利-泰勒对流的发生

摘要-

参照地质问题，数值模拟了Rayleigh-Taylor失稳和多孔介质中密度驱动对流的初始阶段。考虑了两层流体系统，其中下层由纯水形成，而上层由盐的水溶液形成。上层更致密和粘稠。讨论了数值解中对流发生特征时间的确定。揭示了取决于和不取决于初始密度波动的参数。分析了粘度对比对对流流动和传质的开始和发展的影响。估计了与忽略地质流体中的粘度对比有关的定量差异。