Turbulent signals are intermittent with large instantaneous fluctuations. Such large fluctuations lead to small Kolmogorov scales that are hard to resolve in numerical simulations [P. K. Yeung, K. R. Sreenivasan, and S. B. Pope, Effects of finite spatial and temporal resolution in direct numerical simulations of incompressible isotropic turbulence, Phys. Rev. Fluids 3, 064603 (2018)]. The present paper follows the above basic logic, but instead of dissipation events in isotropic turbulence, we study wall-shear stress events in plane channel flow. Wall-shear stress fluctuations are increasingly more intermittent as the Reynolds number increases. Hence, one has to employ higher grid resolutions as the Reynolds number increases in order to resolve a given percentage of wall-shear stress events. The objective of this paper is to quantify effects of the grid resolutions on the rare and high intensity wall-shear stress events. We find that the standard grid resolution resolves about 99% of the wall-shear stress events at ${\text{Re}}_{\tau }=180$. A slightly higher grid resolution has to be employed in order to resolve 99% of the wall-shear stress events at higher Reynolds numbers, and if the standard grid resolution is used for, e.g., a ${\text{Re}}_{\tau }=10000$ channel flow, one resolves about 90%–95% wall-shear stress events.

中文翻译：

---

在直接数值模拟中解决稀有和高强度壁剪应力事件的网格分辨率要求

湍流信号是间歇性的，具有较大的瞬时波动。如此大的波动导致较小的Kolmogorov尺度，很难在数值模拟中解决[P. K. Yeung，K。R. Sreenivasan和S. B. Pope，有限时空分辨率在不可压缩各向同性湍流的直接数值模拟中的影响，物理。流体修订版 3，064603（2018）]。本文遵循上述基本逻辑，但是我们不是研究各向同性湍流中的耗散事件，而是研究平面通道流动中的壁剪应力事件。随着雷诺数的增加，墙剪应力的波动越来越断断续续。因此，随着雷诺数的增加，人们必须采用更高的网格分辨率，以便解决给定百分比的壁剪应力事件。本文的目的是量化网格分辨率对稀有和高强度墙体剪应力事件的影响。我们发现，标准网格分辨率可解决以下情况下约99％的墙剪应力事件：${\text{关于}}_{\tau }=180$。为了解决较高雷诺数下99％的墙剪应力事件，并且如果使用标准网格分辨率（例如）来解决问题，则必须采用稍高的网格分辨率。${\text{关于}}_{\tau }=10000$ 通道流，解决了大约90％–95％的壁剪应力事件。