| 초록 |
Turbulent drag reduction (DR), induced by monodisperse, high molecular weight λ-DNA in a buffer solution under turbulent flow was investigated using a rotating disk apparatus. DR efficiency maintained with time due to the durability of DNA in the moderate turbulent shear flow, and this behavior was compared to water soluble linear flexible long chain polymers such as poly(ethylene oxide) (PEO) and polyacrylamide (PAAM). The maximum drag reducing rotation speed (rpm) of the disk was examined by increasing the rotation speed at two different increasing modes of rpm; continuous and stepwise mode, to investigate a mechanical degradation mechanism of DNA. The mechanical degradation of DNA at high turbulent flow was examined using electrophoresis method, in which the mid-point scission of long chain molecules in high turbulent flow was observed. The drag efficiency for different rotation speeds and for long time scale experiment also supported the explanation about the half-length degradation of DNA and strong resistance of helically stranded DNA structure in turbulent flow compared with water soluble flexible counterparts. |
