Numerical simulation of water entry of two-dimensional structures with complex geometry using a CIP-based model

The present study extends the CIP-based model for the treatment of water entry of two-dimensional structures with complex geometry. The high-order difference model, where the modified ghost-cell immersed boundary method is taken to deal with the moving body with complex geometry more accurately, and the convection term is discretized by the CIP (Constrained Interpolation Profile) method and the free surface is captured by the THING/SW (Tangent of Hyperbola for Interface Capturing with Slope Weighting) method. The benchmarks are the symmetric water entry of a two-dimensional ship section in single degree of freedom and asymmetric water entry of a two-dimensional bionic dolphin section in three degrees of freedom. The impact peaks of local pressure and local force can be accurately predicted. The phenomena of the secondary impact and the air entrapment can be reproduced with fairly good accuracy. A further observation is that diving two-dimensional bionic dolphin section can use the horizontal velocity to increase the maximum penetration depth while maintaining relative stability in the engineering applications. These numerical investigations can help us to understand the influence of complex geometric parameters on hydrodynamic behavior.