Flow friction

Japanese: 流動摩擦 - りゅうどうまさつ（英語表記）flow friction

Friction associated with fluid flow. To make a fluid flow through a pipe, pressure must be applied from one end of the pipe to overcome the frictional force associated with the fluid flow. In a steady state, the two are exactly balanced. Generally speaking, flow friction increases with flow velocity and viscosity, and decreases as the pipe diameter becomes larger. However, looking more closely, flow friction behaves differently for laminar and turbulent flows. In the case of fully developed turbulent flow, the flow friction force is independent of viscosity, and is proportional to 1/2ρ U ² , where ρ is the fluid density and U is the velocity.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

流体の流動に伴う摩擦。パイプの中に流体を流すにはパイプの片端から圧力を加え，流体の流動にともなう摩擦力に打ち勝つ必要がある。定常状態では両者はちょうどバランスしている。一般的にいえば流動摩擦は，流速，粘性とともに増加し，管径が大きくなると小さくなる。ただし，もう少し詳しくみると，流動摩擦は層流と乱流で様子が違う。完全に発達した乱流の場合は流動摩擦力は粘性に無関係になり，流体の密度をρ，速度をUとすると，1/2ρU²に比例する。

出典　株式会社平凡社世界大百科事典第２版について　情報

<<: Ryudokai - Ryudokai

>>: Liquid paraffin - Ryuudou Parafin (English spelling) liquid paraffin