Investigation of the blockage effect on flow past a circular cylinder

Literature review shows that cavitating flows past cylinder have received less attention in comparison to the noncavitating flow. This forms the motivation of the present work. In this work, three flow situations are considered: 6%, 16%, and 20% blockages. The first blockage factor, based on earlier non-cavitation studies, is taken as a reference case where no significant effect of blockage is seen. Airborne noise shows a 3 dB increase in sound level when the flow is blocked 20%. Measurement of static pressure on the surface of these cylinders under non-cavitating condition shows that 9 mm cylinder offers a higher base pressure value and this value increases with an increase in the extent of cavitation. Drag estimated for 9 mm cylinder shows a significant reduction at the lowest cavitation number because of the formation of an elongated cavity. This cylinder also shows a more pronounced cavity structure near inception.