A theoretical study of the effect of gravity modulation on a nanofluid filled porous medium subjected to a constant temperature gradient across is made. In particular the onset of convection in water based nanofluids containing conventional metallic and metal oxide particles ( $Cu$‐water, $A{l}_2{O}_3$‐water, $Ti{O}_2$‐water, and $Ag$‐water) is investigated. The nanofluid behaves more like a single‐phase fluid rather than a conventional solid–liquid mixture. Darcy's law of flow through porous media and Boussinesq approximation are employed. Stability analysis based on the method of small perturbations is performed using the normal mode assumption. The resulting synchronous and asynchronous, restricted to subharmonic, instability modes are predicted directly through the Mathieu functions for different nanoparticle concentrations. It is found that $A{l}_2{O}_3$‐water nanofluid can be effectively used in applications involving gravity modulation.

中文翻译：

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调制纳米流体填充多孔介质中同步和异步对流的开始

对重力调制对纳米流体填充的多孔介质施加恒定温度梯度的影响进行了理论研究。特别是在含有常规金属和金属氧化物颗粒的水基纳米流体中对流的开始（$Cü$-水， $\mathrm{一种}{升}_{\mathrm{2个}}{Ø}_3$-水， $Ť\mathrm{一世}{Ø}_{\mathrm{2个}}$-水，以及 $\mathrm{一种}G$-水）进行了调查。纳米流体的行为更像是单相流体，而不是传统的固液混合物。使用了通过多孔介质的达西定律和Boussinesq近似。基于小扰动方法的稳定性分析是使用法向模态假设进行的。可以通过Mathieu函数直接针对不同的纳米粒子浓度预测最终的同步和异步（仅限于次谐波）不稳定性模式。发现$\mathrm{一种}{升}_{\mathrm{2个}}{Ø}_3$水纳米流体可以有效地用于涉及重力调制的应用中。