Active flow control applied to a ship rudder model

ABSTRACTThe improvement of the performance and efficiency of hydrodynamic control surfaces such as ship rudders is a long sought goal, given economic considerations and the ecological impact of the shipping sector. One major problem limiting the performance of rudders is flow separation at high deflection angles. In this paper, we address this problem using active flow control, a technique first proposed in aerodynamics. A small scale and a large-scale rudder model with realistic geometry were manufactured and equipped with an active flow control system employing the method of pulsed blowing. The actuation system was extensively characterized. Towing tank experiments were conducted up to a Reynolds number of 1.33×106. Data included force measurements for the large-scale model and flow field and force measurements for the small-scale model. The impact of the active control on the flow fields around the small-scale model was characterized. The delay of the flow separation towards a higher angle of attack, accompanied with an increase of the maximum lift forces, was demonstrated for both models.KEYWORDS: Active flow controlship rudderseparation controlfluidic oscillatortowing tankparticle image velocimetry AcknowledgmentsWe express our thanks to Johannes Will for fruitful discussions on the particulars of rudder design.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis project was supported by the German Federal Ministry of Economic Affairs and Climate Action [grant number 03SX496E].