An Efficient Numerical Method for Higher Order Springing Induced Loads

本项目的目的是进一步发展一种基于朗肯源的三维边界元法，以预测波浪中作用在船舶结构上的截面载荷，同时考虑弹簧引起的水弹性效应。波浪诱导力导致共振船舶响应细分为弗劳德-克雷洛夫，辐射和绕射力。 对于高阶弹性，重要的是要考虑与Froude-Krylov力相关的非线性效应。这些力在每个时间步中根据瞬时湿表面计算。关于弹性、绕射力和辐射力，可以用线性的方法来处理.它们在频域中计算，并使用卷积积分在时域中传输。考虑到水弹性效应的流量方程耦合的运动方程（刚性和弹性）。 弹性变形的计算使用模态分解的方法，有效地解决了减少自然模式。一个弗拉索夫梁和三维有限元模型将被使用。此外，简化方法预测流体动力阻尼将开发和验证。要开发的方法进行了广泛的验证，使用的结果，从模型试验和现场方法的基础上，雷诺平均Navier-Stokes方程。

The aim of this project is to further develop a three dimensional boundary element method based on Rankine sources to predict sectional loads acting on ship structures in waves taking into account springing induced hydroelasticity effects. Wave induced forces leading to resonant ship responses are subdivided into Froude-Krylov, radiation and diffraction forces. For higher order springing it is important to consider nonlinear effects related to Froude-Krylov forces. These forces are computed in each time step based on the instantaneous wetted surface. With regard to springing diffraction and radiation forces can be treated in a linear way. They are computed in the frequency domain and transferred in the time domain using convolution integrals. To account for hydroelasticity effects the flow equations are coupled with the equations of motion (rigid and elastic). The elastic deformations are computed using a modal decomposition approach to efficiently solve a reduced set of natural modes. A Vlasov beam and three dimensional Finite-Element models will be used. Further, simplified methods for prediction of hydrodynamic damping will be developed and verified. The methods to be developed are extensively validated using results from model tests and field methods based on Reynolds-Averaged-Navier-Stokes-Equations.