论文部分内容阅读
The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were investigated.Hydrofoils with smooth and rough leading edge were tested for different upstream velocities and incidence angles.The observations clearly revealed that cavitation incipience is enhanced by roughness at incidence angle below 2°.This is in line with the former reports,according to whose roughness element decreases the wettability and traps a larger amount of gas.As a result,surface nucleation is enhanced with an increased risk of cavitation.Surprisingly,for higher incidence angles(>3°),it was found that cavitation incipience is significantly delayed by roughness while developed cavitation is almost the same for both smooth and rough hydrofoils.This unexpected incipience delay is related to the change in the boundary layer structure due to roughness.It was also reported a significant influence of roughness on the dynamic of developed cavitation and shedding of transient cavities.
The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were investigated. Hydrofoils with smooth and rough leading edge were tested for different upstream velocities and incidence angles. The observations clearly revealed that cavitation incipience is enhanced by roughness at incidence angle below 2 ° .This is in line with the former reports, according to where roughness element decreases the wettability and traps a larger amount of gas. As a result, surface nucleation is enhanced with an increased risk of cavitation . Surprisingly, for higher incidence angles (> 3 °), it was found that cavitation incipience is significantly delayed by roughness while cavitation is almost the same for both smooth and rough hydrofoils. Taught unexpected incipience delay is related to the change in the boundary layer structure due to roughness. It was also reported a significant influence of roughness on the dynamic of developed cavitation and shedding of transient cavities.