Numerical simulation of drop oscillation in AC electrowetting  

作　　者：LI XiaoLiang HE GuoWei ZHANG Xing 

机构地区：[1]The State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences

出　　处：《Science China(Physics,Mechanics & Astronomy)》2013年第2期383-394,共12页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the Chinese Academy of Sciences(Grant Nos. KJCX-SW-L08,KJCX2-YW-H18 and KJCX3-SYW-S01);the National Basic Research Program of China(Grant No.2007CB814803);the National Natural Science Foundation of China(Grant Nos.10732090,10872201 and 11023001)

摘　　要：In this paper,a "macroscopic-scale" numerical method for drop oscillation in AC electrowetting is presented.The method is based on a high-fidelity moving mesh interface tracking(MMIT) approach and a "microscopic model" for the moving contact line.The contact line model developed by Ren et al.[Phys Fluids,2010,22:102103] is used in the simulation.To determine the slip length in this model,we propose a calibration procedure using the experimental data of drop spreading in DC electrowetting.In the simulation,the frequency of input AC voltage varies in a certain range while the root-mean-square value remains fixed.The numerical simulation is validated against the experiment and it shows that the predicted resonance frequencies for different oscillation modes agree reasonably well with the experiment.The origins of discrepancy between simulation and experiment are analyzed in the paper.Further investigation is also conducted by including the contact angle hysteresis into the contact line model to account for the "stick-slip" behavior.A noticeable improvement on the prediction of resonance frequencies is achieved by using the hysteresis model.In this paper, a ＂macroscopic-scale＂ numerical method for drop oscillation in AC electrowetting is presented. The method is based on a high-fidelity moving mesh interface tracking （MMIT） approach and a ＂microscopic model＂ for the moving contact line. The contact line model developed by Ren et al. [Phys Fluids, 2010, 22： 102103] is used in the simulation. To determine the slip length in this model, we propose a calibration procedure using the experimental data of drop spreading in DC electrowetting. In the simulation, the frequency of input AC voltage varies in a certain range while the root-mean-square value remains fixed. The numerical simulation is validated against the experiment and it shows that the predicted resonance frequencies for different oscillation modes agree reasonably well with the experiment. The origins of discrepancy between simulation and experiment are analyzed in the paper. Further investigation is also conducted by including the contact angle hysteresis into the contact line model to account for the ＂stick-slip＂ behavior. A noticeable improvement on the prediction of resonance frequencies is achieved by using the hysteresis model.

关 键 词：ELECTROWETTING OSCILLATION contact line model HYSTERESIS slip length 

分 类 号：O35[理学—流体力学]