Using A Non-geometrically Similar Model For The Study Of Scale Effect Of Nominal Wake Field

With the energy efficiency design indicator(EEDI)of new ships,the requirement of efficiency of ships has also been gradually improved.And the research of wake field plays a vital role in energy saving and improvement of the propulsion performance of the ships.Due to the existence of the scale effect of wake field,propeller design and performance prediction are very difficult.The error correction of scale effect followed by the research of scale effect characteristics has been a focus in the field of marine hydrodynamics.Based on numerical calculation,the numerical prediction of wake field was done with six different KCS ship models.By comparison and analysis,the effect of scale effect and stern contraction deformation on wake field is studied.Using the principle of reverse design and Smart Dummy Model(SDM)concept,a stern contraction deformation plan which makes the wake of ship model close to the full scale ship is determined.And then based on the deformation law,the applicability of a 5100 TEU container ship model is discussed.In this paper,the measurement and analysis of flow field is done with Particle Image Velocimetry(PIV)for a SDM deformation scheme of modified wake field scale effect and the KCS model before deformation,and the accuracy of numerical simulation is verified by comparing with the experiment.The scale effect correction based on wake field of the stern deformation provides a new method for the measurement test correction of model nominal wake field due to scale effect.It also makes preparation for the research of SDM propeller-excited force test and SDM self-propulsion test affected by the scale effect.