Investigation of the influence of an interceptor on the inlet velocity distribution of a waterjet-propelled ship using SPIV technology and RANS simulation

Abstract

ABSTRACTTo illustrate the effect of interceptor installation on waterjet-ship wake fields, inlet velocity distribution of a semi-planing waterjet-propelled ship operating under inlet-closed state has been assessed via stereo particle image velocimetry (SPIV) measurements and Reynolds-averaged Navier–Stokes (RANS) simulations. Results reveal that interceptor installation yields substantial drag reduction (6.06% on average) and alts the ship's sailing attitude whilst blocking the water flow in its installation area. Results of SPIV measurements demonstrated good agreement with those obtained via simulations, accurately capturing velocity characteristics in regions affected by fin stabilisers. Interceptor installation was observed to increase boundary-layer thickness near its installation location whilst lowering velocity across the capture area and reducing momentum and energy velocity coefficients by 2.1% and 4.1%, on average, respectively. As observed, changes in the ship's sailing attitude negligibly influenced the velocity distribution; instead, the interceptor's retarding effect was observed to be the main factor driving changes in inlet velocity distribution of waterjet-propelled ships.