en تست و استاندارد Standards and tests پژوهشي Research <span style="font-size:11pt"><span style="line-height:150%"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">The impact of a supercooled droplet on a surface is a primary challenge of many industrial and aeronautical processes. However, in some cases, such as frost formation on vehicle windshields or wind turbine blades, the supercooled droplet collision does not occur in stagnant air. In this study, for the first time, the effects of the air transverse flow (ATF) on the thermal-fluid behavior of a supercooled droplet were investigated numerically. Also, different patterns of a superhydrophobic pillared surface were used in 24 </span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">three-dimensional </span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">simulations in ANSYS Fluent software. The volume of fluid method is chosen for the simulation of the multiphase flow. The freezing model is improved by the supercooling temperature consideration method. The results show that the ATF velocity reduces the separation time exponentially and helps the droplet bounce from the surface before freezing inception. However, the excessive increase in ATF velocity</span></span></span> <span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">has the opposite effect and may prevent the droplet from detaching the surface due to notable drag. The best value of the ATF velocity is obtained to be 8 </span></span></span><m:omath><i><span style="font-size:12.0pt"><span style="line-height:150%"><span cambria="" math="" style="font-family:"><m:r>m/</m:r><m:r>s</m:r></span></span></span></i></m:omath><span style="font-size:11.0pt"><span style="line-height:107%"><span calibri="" style="font-family:"><span style="position:relative"><span style="top:4.0pt">&nbsp;</span></span></span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">, which reduces the separation time exponentially from 16.3 </span></span></span><m:omath><i><span style="font-size:12.0pt"><span style="line-height:150%"><span cambria="" math="" style="font-family:"><m:r>ms</m:r></span></span></span></i></m:omath><span style="font-size:11.0pt"><span style="line-height:107%"><span calibri="" style="font-family:"><span style="position:relative"><span style="top:4.0pt">&nbsp;</span></span></span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">&nbsp;to 12.5 </span></span></span><m:omath><i><span style="font-size:12.0pt"><span style="line-height:150%"><span cambria="" math="" style="font-family:"><m:r>ms</m:r></span></span></span></i></m:omath><span style="font-size:11.0pt"><span style="line-height:107%"><span calibri="" style="font-family:"><span style="position:relative"><span style="top:4.0pt">&nbsp;</span></span></span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">&nbsp;for a cold surface with a simple pillar pattern. The separation time</span></span></span> <span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">is entirely affected by the simulation conditions and varies from 11.85 </span></span></span><m:omath><i><span style="font-size:12.0pt"><span style="line-height:150%"><span cambria="" math="" style="font-family:"><m:r>ms</m:r></span></span></span></i></m:omath><span style="font-size:11.0pt"><span style="line-height:107%"><span calibri="" style="font-family:"><span style="position:relative"><span style="top:4.0pt">&nbsp;</span></span></span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">&nbsp;to 29.2 </span></span></span><m:omath><i><span style="font-size:12.0pt"><span style="line-height:150%"><span cambria="" math="" style="font-family:"><m:r>ms</m:r></span></span></span></i></m:omath><span style="font-size:11.0pt"><span style="line-height:107%"><span calibri="" style="font-family:"><span style="position:relative"><span style="top:4.0pt">&nbsp;</span></span></span></span></span><span style="font-size:12.0pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times="">. The maximum spreading factor, despite the separation time, is seriously influenced by the void fraction percentage of different pillared surfaces and varies from 1.53 to 1.69.</span></span></span></span></span></span> Air transverse flow, superhydrophobic pillared surface, supercooled droplet, impacting-freezing simulation, vehicle windshields 4449 4463 http://ase.iust.ac.ir/browse.php?a_code=A-10-814-1&slc_lang=en&sid=1 Seyed Reza Hosseini reza_hosseini@mecheng.iust.ac.ir 180031947532846004747 180031947532846004747 No School of Mechanical Engineering, Iran University of Science & Technology mahdi moghimi moghimi@iust.ac.ir 180031947532846004748 180031947532846004748 Yes School of Mechanical Engineering, Iran University of Science & Technology Norouz Mohammad Nouri mnouri@iust.ac.ir 180031947532846004749 180031947532846004749 No School of Mechanical Engineering, Iran University of Science & Technology