回転円板の流体抵抗におよぼすすきまとみぞの影響

抄録

Experiments on a rotating grooved disc in a closed grooved vessel, were carried out with various clearances, especially very small axial clearances, and over wider range of Reynold's number. From these results the effects of axial clearance S, pitch p and depth T of grooves on the resisting coefficient are determined as follows : (1) When the axial clearahces are very small and the surfaces are smooth, resisting coefficient C_f is in proportion to R₆^-5/6in larminar flow region, and to R_e^-1/4 in turbulent flow region, and independent of R_e in transitional region. (2) C_f takes a minimum value at S/d≒0.0066, where d is the disc diameter, irrespective of the exsistance of grooves. In general, grooves have little infiuences on S/d. (3) C_f of smooth or grooved disc. in grooved vessel takes a minimum value, when p/d= 0.088, T/d=0.0066. The combination of a smooth disc and a grooved vessel is desirable in order to decreases C_f in larminar flow region. On the other hand, in turbulent flow region, the combination of a grooved disc and a grooved vessel is prefered.