不同舰船机库外形下艉流场特征数值模拟研究

Numerical calculation of frigate ship airwake with different hangar shapes

为了研究舰船艉流场特性,采用基于SA湍流模型的非定常脱体涡模拟(Detached-Eddy Simulation,DES)对典型护卫舰船艉流场进行数值模拟,研究三种不同机库外形在0°与右舷45°自由来流风向角下的非定常特性以及对舰船艉部大分离流场的影响,尤其是对舰载直升机起降环境的影响,并推导了快速预测舰船艉部回流区范围的经验公式。通过与风洞试验数据对比,验证了该计算方法的准确性。由非定常计算的时均结果与瞬时结果表明,相比两侧较低高度的机库外形,等高外形的机库不利于直升机的舰面安全起降;通过合理的降低机库高度可以有效地改善艉部飞行甲板处的起降环境;研究结果验证了经验公式对回流区范围预测的有效性。研究成果可为工程应用提供参考。

In order to research the characteristics of frigate ship airwaves influenced by three different hanger shapes for a headwind and the Green 45° case, Computational Fluid Dynamics (CFD) simulations were performed by using Detached-Eddy Simulation method based on Spalart-Allmaras turbulence model with unstructured grids. The results turned to be correct and feasible by comparing with the wind-tunnel data, indicating the capability of DES to resolve the unsteady large-scale turbulent features. The results show that equal height hangar shapes are not conducive to the safety when launching and recovering of helicopters to naval ships, compared by the same hanger height but with both lower sides. By reducing hangar height reasonably, the launching and recovering environment on flight deck could be improved. The results verify the validity of the empirical equation for the prediction of the recirculation zone, and can provide an important reference for the engineering study.