基于DES的舰船空气尾流场特性分析

舰船上层建筑后方产生湍流尾流场会对舰载直升机的操纵产生严重威胁。采用CFD方法对舰船空气尾流场的特性进行分析研究,突破了雷诺时均方法的局限性,使用分离涡模拟(DES)方法求解瞬态舰船尾流场,按照一定频率采样流场数据,得出的平均流场明显比RANS方法的结果更贴近实验数据,证明了此方法的有效性。同时,运用DES方法直观地观察尾流场的涡特性、流动分离和再附着等特征,发现涡结构及其不对称性是舰船空气尾流场的主要特征,涡强度在烟囱处突然增强,可能对直升机的操纵产生不利影响。

Investigation on the numerical simulation of ship airwake based on DES

The superstructures of ships can generate different scales of vortices, a threat to the helicopter maneuvering. Aiming at the problem, the characteristics of the ship airwake is investigated in this paper with CFD method instead of the traditional Reynold-Averaged Navier-Stokes(RANS) method. In particular, Detached Eddy Simulation(DES) method is adopted to investigate the transitional flow field. Through processing the transitional data, a mean flow field is obtained, which agrees well with the experimental results, validating the effectiveness and accuracy of DES over RANS in solving ship airwake. Furthermore, by observing the transitional vortices, flow separation, and reattach of ship airwake with DES method, it is concluded that vortexes' asymmetry is the main feature in wake flow, and the vortical magnitude sharply increases at the chimney, inducing a severe threat to the helicopter.