利用多體耗散動力學的模擬方法來研究奈米液滴在俱有弱缺陷的表面上的穩定滑動行為及隨機運動。利用滑移長度來代表基材表面粗糙度對流體的影響，而該表面的滑移長度是從流動液膜所產生的速度分佈中獲得的。我們發現滑移長度隨著缺陷密度的增加而下降。奈米液滴的滑動速度和施予的外力大小之間有著線性關係，而此線性關係之斜率則提供了奈米液滴的移動率，並且得知在弱缺陷的表面上是沒有接觸線停滯的情況。根據Navier條件，得出一個簡單的關係式，並指出移動率與滑移長度成正比，但與黏度和接觸面積的乘積成反比。我們的模擬結果與理論預測非常吻合。在沒有外力的情況下，觀察到奈米液滴的二維布朗運動，並且其均方位移會隨著缺陷密度的增加而減小。擴散率與移動率成正比，且符合愛因斯坦關係。此結果表示，熱擾效應能夠克服由弱缺陷引起的接觸線停滯。;Steady slide and random motion of nanodroplets on surfaces with weak defects is investigated by Many-body Dissipative Dynamics. The surface roughness is characterized by the slip length acquired from the velocity profile associated with the flowing film. The slip length is found to decline with increasing the defect density. The linear relationship between the sliding velocity and driving force gives the mobility and reveals the absence of contact line pinning. On the basis of the Navier condition, a simple relation is derived and states that the mobility is proportional to the slip length and the reciprocal of the product of viscosity and contact area. Our simulation results agree excellently with the theoretical prediction. In the absence of external forces, a two-dimensional Brownian motion of nanodroplets is observed and its mean square displacement decreases with increasing the defect density. The diffusivity is proportional to the mobility, consistent with the Einstein relation. This consequence suggests that thermal fluctuations are able to overcome contact line pinning caused by weak defects.
