基于WENO-分段线性格式的直升机流场数值模拟

Numerical simulation for flow field of helicopters based on WENO-piecewise linear scheme

发展了一套适合于格心格式求解器的基于加权本质无振荡(WENO)-分段线性格式的旋翼/机身气动干扰高精度CFD计算方法。应用该方法对多种旋翼/机身组合模型前飞算例进行了数值模拟,计算得到的机身表面压力系数分布与实验结果吻合良好,说明了该方法对旋翼/机身气动干扰研究的有效性。之后进一步将该方法应用到悬停状态的X3构型复合式高速直升机旋翼/机翼/螺旋桨组合模型的复杂流场模拟中,并与悬停状态孤立旋翼和旋翼/机翼组合模型的流场进行了对比。研究发现:机翼对旋翼下洗流起阻滞作用,引起机翼下方不规则流动,且螺旋桨滑流与旋翼下洗流会相互干扰产生一定的偏折,旋翼下洗流速度更大,螺旋桨滑流会产生明显的向下偏折。

A high-precision CFD method based on WENO(weighted essentially non-oscillatory)-piecewise linear scheme was established for numerical simulation on the rotor/fuselage aerodynamics interaction flow field.And it was suitable for the CFD solver of cell-centered scheme.The pressure coefficient on the surface of the fuselage of different rotor/fuselage model examples in forward flight was calculated by the method,and the calculation results were in good agreement with the experimental results,verifying the effectiveness of the calculation method.Then,the method was extended to simulate the flow field of X3 compound high-speed helicopter rotor/wing/propeller model in hover,and the flow field was compared with flow field of single rotor and rotor/wing model in hover.The results showed that the wing acted as a retarder on the downwash of rotor,causing the irregular flow under the wing.Furthermore,the slipstream of propeller and the downwash of rotor interfered with each other to produce a certain deflection,and the speed of downwash was faster than the speed of slipstream,the downward deflection of propeller slipstream was significant.