Hydrodynamic characteristics of multiple-rudder configurations

The manoeuvring performance of inland vessels is even more crucial than that of seagoing ships due to more complex navigation environment. One of the most effective possibilities to improve ship manoeuvrability is to change the rudder configuration. Twin or even quadruple rudders and high-lift profiles are widely applied to inland vessels. When inland vessels equip with multiple rudders, the interaction effects between the rudders affect the hydrodynamic characteristics of each rudder. This paper presents a study on these interaction effects using two-dimensional Reynolds-averaged Navier–Stokes (RANS) methods. Various twin-rudder and quadruple-rudder configurations with different profiles and spacing among the multiple rudders were studied. RANS simulations were performed with a k−ω SST turbulence model and a pressure-based coupled algorithm. Series of NACA, IFS and wedge-tail profiles were tested. Regression formulas have been proposed for the twin-rudder lift and drag coefficients. Finally, interaction effects on multiple rudder hydrodynamics have been summarised.