NAME

Sun Na

TITLE

Lecturer

SCHOOL

School of Mechanical Engineering

DEPARTMENT

MechanicalEngineering

OFFICE ADDRESS

Room 304, Teaching Building No.1, Beijing Institute of Technology

POST CODE

100081

TELEPHONE

010-68912719

E-MAIL ADDRESS

nsun@bit.edu.cn

Research and Teaching Interest

My research interest is the drag reduction mechanism of fish. Swimming fish will take the water in the wall-bounded area surrounding its skin moving forward with it. Therefore, the skin-friction resistance of swimming fish is generated by the shearing motions of water molecules between two adjacent water layers in the wall-bounded area. Since hydrogen bonding is the dominant binding energy between water molecules, it will help us understand the skin-friction drag-reducing mechanism of fish by investigating how fish weakens the hydrogen bonding to reduce the shearing actions of water molecules.

In this study, a bionics method was used to solve the problems of high-energy consumption, limited speed and restrained distance of underwater vehicles caused by skin friction. The bioelectricity of fish was measured and the influence of the charge effect caused by bioelectricity on hydrogen bonding of water molecules was analyzed by a laser Raman spectroscopy for revealing the mechanism of skin-friction drag reduction of fish. An electrode potential controllable (EPC) specimen was fabricated to mimic the electrophysiology characteristics of fish. The drag-reducing behaviors of the EPC specimens were analyzed by a circulation high-speed water tunnel and a particle image velocimetry (PIV) system. Mimicking this mechanism, a novel bio-inspired paint was designed and sprayed on vessel mode surfaces to form coatings with drag-reducing and self-polishing properties.

Selected Publications and patents

1. N. Sun, H.Y. Shan, H. Zhou, et al, Adhesion resistance surfaces against clay resulting from biomimetic adaptation, Surface& Coatings Technology, 2012, 206 (16): 3559-3565
2. N. Sun, H.Y. Shan, H. Zhou, et al, Friction and wear behaviors of compacted graphite iron with different biomimetic units fabricated by laser cladding, Applied Surface Science, 2012, 258 (19): 7699-7706
3. N. Sun, T.H. North, D.R. Chen, et al, Influences of welding parameters on mechanical properties of AZ31 friction stir spot welds, Science and Technology of Welding and Joining, 2012, 17 (4): 304-308

Achievements and Awards

Professional Membership/Academic Appointments