抄録
Regarding the air entrainment into a suction pipe which is vertically inserted into a suction sump across a free surface, critical submergence S_c are specified concerning six parameters, such as the Froude number Fr, the Reynolds number Re, the Weber number We, back clearance X, sump breadth B and bottom clearance Z. Here, all parameters are non-dimensionalized by suction-pipe outer diameter D and suction-pipe intake velocity V_i. Consequently, the authors confirmed that the surface-tension effect is negligible at We≥20, and that the viscous effect become enough small at Re≥3.2×10^4, while Fr effect is significant. Z/D effect also becomes small at Z/D≥2.5. Most of geometric effects can be explained on the basis of the Fr-S_c/D relation.
