Drag Reducton of Pipe Wall For Fluid Flow due to Injected Polymer Solution - III. Consideration of Entrance Region Flow of Drag Reducing Fluids-

고분자용액에 의한 유체수송관벽의 저항감소 -III. 저항감소유체의 입구흐름 영역에 대한 고찰-

As a part of studies of drag reduction phenomenon, at the entrance flow region of abrupt contraction tube flowing water, dilute and concentrated drag reducing polymer solutions contraction losses are estimated experimentally. Futher more, entrance lengths are considered theoretically and are measured experimentally. In the present experiment, fluid temperature is fixed l$0^{\circ}C$ and flow rates are 3,000