A computational framework for pump-jet hydrodynamic performance incorporating unsteady free-wake vortex dynamics

The internal flow field of a pump-jet propulsor is highly complex, often exhibiting unsteady performance characteristics, which necessitates the development of high-precision unsteady performance prediction methods. The wake vortex model plays a critical role in unsteady performance calculations. However, conventional approaches are based on rigid wake vortex models. These models employ fixed wake grids and update numerical solutions by transferring dipole strength. This methodology has a critical limitation: it fails to capture the dynamic evolution of the wake morphology. Such evolution is caused by changes in the flow field that occur during propulsor rotation. To address this issue, this study proposes a spatiotemporally adaptive unsteady free wake vortex numerical model based on unsteady potential flow theory. By iteratively updating the wake grid at each time step, the prediction accuracy of hydrodynamic performance is improved. Comparative analysis reveals the evolution characteristics of unsteady free wake vortices and their influence on hydrodynamic performance, validating the effectiveness of the proposed model in enhancing prediction reliability.