Study of cavitation characteristics behind cylindrical irregularity in cavitation region

This paper develops an equation of energy conservation for cavitation flow region based on the equations of cavitation bubble and bubble motion.For the cavitation region behind cylindrical irregularity,numerical simulations are presented to demonstrate the effects of cavitation under two different flow velocities.An experiment was conducted in an open-loop water tunnel to test a cylindrical irregularity of 5mm high and 6mm in bottom diameter under the condition of flow aeration by an aeration hole of 5mm in diameter.The results indicate that bubble radius gradually decreases with increase of air concentration at a fixed flow velocity while it becomes smaller if air concentration is higher at the higher flow velocity.Cavitation number for a fixed velocity increases with air concentration,and the peak cavitation number at the lower velocity is larger than that at the higher velocity.The experimental and numerical results agree very well.