Department of Mathematics, Hacettepe University, Beytepe, Ankara 06532, Turkey.
Comput Methods Programs Biomed. 2020 Apr;187:105171. doi: 10.1016/j.cmpb.2019.105171. Epub 2019 Nov 3.
The hydrodynamic stability of nanofluids of one phase is investigated in this paper based on linear stability theory. The overall thrust here is that the linear stability features of nanofluids can be estimated from their corresponding working fluid, at least in special circumstances.
The approach uses the adjusting parameter to make assertions about stability. This is possible by certain correlations between the resulting eigenvalues.
It is shown that as the nanoparticles are added, the mean flow of nanofluids is slightly modified and the resulting eigen space of nano disturbances is built on the corresponding pure flow eigen space of perturbations. Several fluid dynamics problems are revisited to verify the usefulness of the obtained correlations.
The presented approach in this work serves us to understand the stabilizing/destabilizing effects of nanofluids as compared to the standard base fluids in terms of stability of viscous/inviscid and temporal/spatial senses. To illustrate, the critical Reynolds number in a traditional boundary layer flow is shown to be pushed to higher values with the dispersed nanoparticles in a working fluid, clearly implying the delay in transition from laminar to turbulent state.
本文基于线性稳定性理论研究了单相纳米流体的流体动力稳定性。这里的总体思路是,至少在特殊情况下,可以根据相应的工作流体来估计纳米流体的线性稳定性特征。
该方法使用调整参数来对稳定性做出断言。这是通过相关的特征值之间的某些关联来实现的。
结果表明,随着纳米颗粒的添加,纳米流体的平均流动略有改变,纳米扰动的特征空间建立在相应的纯流扰动特征空间之上。重新研究了几个流体动力学问题,以验证所获得的相关性的有效性。
本文提出的方法可用于理解纳米流体相对于标准基液在粘性/无粘性和时/空稳定性方面的稳定/失稳效应。例如,在工作流体中添加分散的纳米颗粒会将传统边界层流中的临界雷诺数推至更高的值,这显然意味着从层流向湍流状态的转变延迟。