Dynamics of stabilizer fins on the waterjet-propelled ship

Abstract

An evaluation of the stabilizer fin's influence on the flow fields of a waterjet-propelled ship was studied by the Reynolds-Averaged Navier-Stokes (RANS) method. Model- and full-scale simulations of the unsteady multiphase flow were carried out both in the bare hull and the self-propulsion conditions. The reliability of grid arrangement and numerical methods was confirmed by the uncertainty analysis of the flow fields. The results indicated that the existence of stabilizer fins altered the turbulent boundary layer distribution around the hull and such disturbance extended to the capture areas of the waterjet's ingested flow. The discrepancy of the outer waterjet (OW) and the inner waterjet (IW) axial velocity distributions resulted in the difference of velocity non-uniformity in the pump inflow plane, and it also caused a relatively larger decrease in the duct efficiency of the OW. With respect to the scale effect of the flow fields, a relatively thinner boundary layer thickness and a higher non-uniformity of the internal flow were observed due to a higher turbulence in the full-scale simulation. It was noted that the model-scale computations underestimated the momentum velocity coefficients at station 1a, while they overestimated the duct efficiency in all cases, with or without the stabilizer fins.