Experimental study of cavitation control on a hydrofoil with bio-inspired riblets using proper orthogonal decomposition

• We experimentally studied cavitation control around a hydrofoil using different a riblet structures. • Cavitation structures were captured through high-speed camera and analyzed using image processing proper orthogonal decomposition (POD). • The riblet structures substantially controlled the cavitation and chaotic behavior on the hydrofoil surface. • Cavitationbehind the hydrofoil and tip-vortex cavitation were reduced for the hydrofoil with riblet structures. This experimental study examined a passive cavitation control method on a NACA 0015 hydrofoil. We utilized mesoscale bio-inspired riblets, known as scalloped riblets, on the suction side of the hydrofoil at the leading edge for passive control. We used high-speed imaging and measurements of pressure changes to investigate cavitating flow over a hydrofoil with and without riblets. The experiment was conducted at Reynolds numbers of 0.5 × 10 6 and an angle of attack of 10 degrees, encompassing three stages of cavitation (partial and cloud cavitation). The results indicate that the reduced momentum of the re-entrant jet significantly lessened cloud cavitation shedding on the hydrofoil’s suction surface. The intensity of shock waves is significantly reduced due to the presence of riblets on the hydrofoil. The use of riblets can mitigate cavitation erosion, as evidenced by a decrease in cavity size and reduced intensity. Further, the depth analysis was carried out with proper orthogonal decomposition (POD). It is found that higher-frequency peaks are associated with re-entrant jets, while lower-frequency peaks correspond to shock wave shedding. This study offers novel insights into mitigating the detrimental impacts of cavitation through the use of bio-inspired riblets, pertinent to numerous engineering applications.