Molecular dynamics simulation of frictional properties of Couette flow with striped superhydrophobic surfaces under different loads

2019 ◽  
Vol 21 (32) ◽  
pp. 17786-17791 ◽  
Author(s):  
Chengzhi Hu ◽  
Dawei Tang ◽  
Jizu Lv ◽  
Minli Bai ◽  
Xiaoliang Zhang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Critical Load ◽  
Couette Flow ◽  
Friction Reduction ◽  
Superhydrophobic Surfaces ◽  
Dynamics Simulation ◽  
Frictional Properties

There was a critical load (Pcrit), such that the friction-reduction of superhydrophobic surfaces appeared only when the load < Pcrit.

Molecular Dynamics Simulation on the Friction Properties of Couette Flow With Superhydrophobic Rough Surfaces Under Different Load

2019 ◽  
Author(s):  
Chengzhi Hu ◽  
Dawei Tang ◽  
Jizu Lv ◽  
Minli Bai ◽  
Xiaoliang Zhang
Keyword(s):  
Molecular Dynamics ◽  
Couette Flow ◽  
Load Condition ◽  
Friction Reduction ◽  
Dynamics Simulation ◽  
Flow Properties ◽  
Opposite Trend ◽  
Low Load ◽  
High Load Condition ◽  
Dynamics Simulations

Abstract To reveal the effect of superhydrophobic rough surface on the friction properties, molecular dynamics simulations are used to study the friction properties of Couette flow. In particular, the influence of load on the flow properties is considered in this work. Results show that there is a critical load (Pcrit), and the friction-reduction properties of superhydrophobic surfaces with stripes are only presented when the load is smaller than the Pcrit. With the decrease in the distance between stripes, the Pcrit is increased. Under a low load, the friction force is increased with increasing the distance between stripes. However, under high load condition we observe an opposite trend. The height of stripe has little impacts on the Pcrit.

scholarly journals On the Microscopic Flow Characteristics of Nanofluids by Molecular Dynamics Simulation on Couette Flow

2012 ◽  
Vol 5 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Wenzheng Cui ◽  
Minli Bai ◽  
Jizu Lv ◽  
Xiaojie Li
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Heat Transfer Enhancement ◽  
Couette Flow ◽  
Flow Characteristics ◽  
Dynamics Simulation ◽  
Shear Direction ◽  
Transfer Enhancement ◽  
Microscopic Flow

Adding a small amount of nanoparticles to conventional fluids (nanofluids) has been proved to be an effective way for improving capability of heat transferring in base fluids. The change in micro structure of base fluids and micro motion of nanoparticles may be key factors for heat transfer enhancement of nanofluids. Therefore, it is essential to examine these mechanisms on microscopic level. The present work performed a Molecular Dynamics simulation on Couette flow of nanofluids and investigated the microscopic flow characteristics through visual observation and statistic analysis. It was found that the even-distributed liquid argon atoms near solid surfaces of nanoparticles could be seemed as a reform to base liquid and had contributed to heat transfer enhancement. In the process of Couette flow, nanoparticles moved quickly in the shear direction accompanying with motions of rotation and vibration in the other two directions. When the shearing velocity was increased, the motions of nanoparticles were strengthened significantly. The motions of nanoparticles could disturb the continuity of fluid and strengthen partial flowing around nanoparticles, and further enhanced heat transferring in nanofluids.

Electric Field Effects on Buckling Analysis of Boron–Nitride Nanotubes Using Surface Elasticity Theory

2020 ◽  
Vol 20 (12) ◽  
pp. 2050137
Author(s):  
Hamid Zeighampour ◽  
Yaghoub Tadi Beni ◽  
Yaser Kiani
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Boron Nitride ◽  
Electric Field ◽  
Critical Load ◽  
Elasticity Theory ◽  
Surface Elasticity ◽  
Boron Nitride Nanotubes ◽  
Dynamics Simulation ◽  
Applied Theory

In this paper, the axial buckling of boron nitride nanotubes (BNNTs) is investigated by considering the effects of surface and electric field. To achieve this purpose, the surface elasticity theory is exploited and the results are compared with the molecular dynamic simulation in order to validate the accuracy of the applied theory. In the molecular dynamics simulation, the potential between boron and nitride atoms is considered as Tersoff type. The Timoshenko beam theory is adopted to model BNNT. Moreover, two types of zigzag and armchair BNNTs are considered. In this study, the effects of surface, electric field, length, and thickness of BNNT on the critical buckling load are investigated. According to the results, the critical load of zigzag BNNT depends on the electric field. However, the electric field would not affect the critical load of the armchair BNNT. It should be noted that the surface residual tension and surface Lamé’s constants of BNNT have considerable impact on the critical load of BNNT. For lower values of electric field and smaller dimensions of BNNT, the critical load would be more dependent on the surface effect regarding the results. Furthermore, as an efficient non-classical continuum mechanic approach, the surface elasticity theory can fill the potential gap between the classical continuum mechanic and molecular dynamics simulation.

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