Sammendrag
This paper presents a numerical study of the ventilation phenomenon based on model tests of a pushing thruster with variable advance ratios at a constant immersion depth to radius ratio h/R=1.6. This study uses STAR-CCM+, a commercial CFD code which uses a VOF formulation (Volume Of Fluid) in order to capture the free surface and the air caught by the thruster.
Variations of the methodology are conducted in order to compute propeller thrust and torque and compare them with experimental measurements. The results show that it is still a challenge to numerically evaluate the thrust and torque losses in a partially or highly ventilated regime. However, the ventilation inception can be correctly detected which is one of the most important information from a practical point of view because, in most of the cases, severe ventilation must be totally avoided to prevent important mechanical damages.
Full scale simulations are also carried out in order to investigate the scale effects. Numerical differences are observed between the model and the full scale for advance coefficients below the critical advance coefficient.
Variations of the methodology are conducted in order to compute propeller thrust and torque and compare them with experimental measurements. The results show that it is still a challenge to numerically evaluate the thrust and torque losses in a partially or highly ventilated regime. However, the ventilation inception can be correctly detected which is one of the most important information from a practical point of view because, in most of the cases, severe ventilation must be totally avoided to prevent important mechanical damages.
Full scale simulations are also carried out in order to investigate the scale effects. Numerical differences are observed between the model and the full scale for advance coefficients below the critical advance coefficient.