Title: Preliminary experimental investigation on the interaction of a subaqueous dune like granular structure with a turbulent open channel flow Show Chinese title

Title: 关于水下类似沙丘的颗粒结构与湍流明渠水流相互作用的初步实验研究

Abstract: We study the interaction of a subaqueous dune like granular structure with a turbulent open channel flow experimentally using optical diagnostics in the Reynolds and Froude parameter space ($7.7{\times}10^3<Re<3.8{\times}10^4$, $0.1<Fr<0.4$). Interactions between the turbulent flow and the granular structure give rise to transient erosion-deposition dynamics leading to various types of particle transport. The subaqueous structures in the channel bed evolves due to shear-stress-induced erosion, gravity-driven deposition, and subsequent particle transport. We study the centroid motion and the granular structure shape evolution. At lower end of our $Re-Fr$ parameter space, we observe no erosion and the structure remains at rest. At intermediate values of $Re$ and $Fr$, we observe very slow erosion and the granular structure moves vere slowly as a rigid body without significant shape deformation. Higher values of $Re$ and $Fr$ causes vortex formation at the upstream of the dune resulting in stronger erosion, rapid shape deformation and relatively higher translation velocity of the centroid. Show Chinese abstract

Abstract: 我们通过光学诊断技术在雷诺数和弗劳德数参数空间（$7.7{\times}10^3<Re<3.8{\times}10^4$,$0.1<Fr<0.4$）内实验研究了水下类似沙丘的颗粒结构与湍流明渠流的相互作用。湍流与颗粒结构之间的相互作用导致瞬态侵蚀-沉积动力学，从而引起各种类型的颗粒传输。 由于剪切应力引起的侵蚀、重力驱动的沉积以及随后的颗粒传输，明渠床中的水下结构会发生演变。 我们研究了质心运动和颗粒结构形状的演变。 在我们的$Re-Fr$参数空间的低端，我们观察到没有侵蚀，结构保持静止。 在$Re$和$Fr$的中间值时，我们观察到非常缓慢的侵蚀，颗粒结构以刚体形式缓慢移动，而没有显著的形状变形。 $Re$和$Fr$的较高值会导致沙丘上游形成涡旋，从而引发更强的侵蚀、快速的形状变形和相对较高的质心平移速度。