COMPUTATIONAL FLUID DYNAMICS OF FOUR-QUADRANT MARINE-PROPULSOR FLOW

摘要

Computational fluid dynamics results are presented of four-quadrant flow for marine-propulsor P4381. The solution method is unsteady three-dimensional incompressible Reynolds-averaged Navier-Stokes equations in generalized coordinates with the Baldwin-Lomax turbulence model. The method was used previously for the design condition for marine-propulsor P4119, including detailed verification and validation. Only limited verification is performed for P4381. The validation is limited by the availability of performance data and ring vortex visualizations for the crashback conditions. The predicted performance shows close agreement with the data for the forward and backing conditions, whereas the agreement is only qualitative for the crashahead and crashback conditions and requires an ad hoc cavitation correction. Also, the predicted ring vortex for the crashback condition is in qualitative agreement with the data. Extensive calculations enable detail description of flow characteristics over a broad range of propulsor four-quadrant operations, including surface pressure and streamlines, velocity distributions, boundary layer and wake, separation, and tip and ring vortices. The overall results suggest promise for Reynolds-averaged Navier-Stokes methods for simulating marinepropulsor flow, including off-design. However, important outstanding issues include additional verification and validation, time-accurate solutions, and resolution and turbulence modeling for separation, and tip and ring vortices.