T-Craft Calm Water Resistance and Motions, and Seakeeping in Regular Waves

Prescribed and variable cushion pressure models, and rigid, hinged and imaginary seal models are implemented in URANS/DES solver CFDShip-Iowa V4 and validated for TCraft resistance, motions and seakeeping. The hinged-seal model resistance predictions are within 8.5% of the experiments, better than rigid and imaginary seal without resistance models. However, they are numerically expensive and not well suited for transient simulations. The variable cushion pressure model (due to motions) predicts impulsive pitch and heave motions better than the prescribed model, where the results are within 5.4% of the experiment. The seakeeping response show a peak close to the natural frequency and approach unity for larger wavelengths. V4 predictions compare well with the experiments for smaller wavelengths, but differences are observed for larger wavelengths. The differences are probably due to overprediction of the aft and underprediction of the forward cushion pressures. A variable cushion pressure model with leakage and fan flows and an imaginary seal model with resistance are identified to be well suited for T-Craft applications, which will be investigated next.