Mechanical Engineering Department, College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Alexandria, 1029, Egypt.
Sci Rep. 2022 Aug 1;12(1):13166. doi: 10.1038/s41598-022-16079-5.
The study of turbulence in physiologic blood flow is important due to its strong relevance to endothelial mechanobiology and vascular disease. Recently, Saqr et al. (Sci Rep 10, 15,492, 2020) discovered non-Kolmogorov turbulence in physiologic blood flow in vivo, traced its origins to the Navier-Stokes equation and demonstrated some of its properties using chaos and hydrodynamic-stability theories. The present work extends these findings and investigates some inherent characteristics of non-Kolmogorov turbulence in monoharmonic and multiharmonic pulsatile flow under ideal physiologic conditions. The purpose of this work is to propose a conjecture for the origins for picoNewton forces that are known to regulate endothelial cells' functions. The new conjecture relates these forces to physiologic momentum-viscous interactions in the near-wall region of the flow. Here, we used high-resolution large eddy simulation (HRLES) to study pulsatile incompressible flow in a straight pipe of [Formula: see text]. The simulations presented Newtonian and Carreau-Yasuda fluid flows, at [Formula: see text], each represented by one, two and three boundary harmonics. Comparison was established based on maintaining constant time-averaged mass flow rate in all simulations. First, we report the effect of primary harmonics on the global power budget using primitive variables in phase space. Second, we describe the non-Kolmogorov turbulence in frequency domain. Third, we investigate the near-wall coherent structures in time and space domains. Finally, we propose a new conjecture for the role of turbulence in endothelial cells' mechanobiology. The proposed conjecture correlates near-wall turbulence to a force field of picoNewton scale, suggesting possible relevance to endothelial cells mechanobiology.
研究生理血流中的湍流很重要，因为它与内皮细胞生物力学和血管疾病有很强的相关性。最近，Saqr 等人（Sci Rep 10, 15,492, 2020）在体内生理血流中发现了非 Kolmogorov 湍流，其起源可追溯到纳维-斯托克斯方程，并使用混沌和流体动力学稳定性理论来证明其部分特性。本工作扩展了这些发现，并在理想生理条件下研究了单谐波和多谐波脉动流中非 Kolmogorov 湍流的一些固有特性。本工作的目的是提出一个关于调节内皮细胞功能的皮牛顿力起源的假设。这个新的假设将这些力与流动近壁区的生理动量粘性相互作用联系起来。在这里，我们使用高分辨率大涡模拟（HRLES）研究了[Formula: see text]直管中的脉动不可压缩流。模拟了牛顿和 Carreau-Yasuda 流体流动，在[Formula: see text]下，每个流动都由一个、两个和三个边界谐波表示。在所有模拟中保持恒定的时均质量流量来进行比较。首先，我们使用相空间中的原始变量报告了主要谐波对全局功率预算的影响。其次，我们描述了频域中的非 Kolmogorov 湍流。第三，我们研究了时-空域中的近壁相干结构。最后，我们提出了一个关于湍流在内皮细胞生物力学中作用的新假设。该假设将近壁湍流与皮牛顿尺度的力场相关联，这表明其与内皮细胞生物力学可能存在相关性。
