摘要
为提高直升机旋翼黏性涡流场计算流体力学（CFD）的计算精度及降低数值耗散,发展了一套基于五阶加权本质无振荡（WENO）格式的旋翼非定常涡流场数值计算方法。采用运动嵌套网格方法生成围绕前飞状态旋翼的网格系统,以Navier-Stokes方程作为主控方程,湍流模型采用一方程Spalart-Allmaras模型。为了提高旋翼流场中对涡的形成、演化等发展过程的模拟精度,采用高间断分辨率的Roe-WENO格式计算对流通量。对状态变量的插值,选取适当的加权因子,通过多个重构模板的凸组合来构造五阶WENO格式,在交界面附近获得具有五阶精度的状态变量。为了提高计算效率,采用高效的隐式LU-SGS（Lower-Upper Symmetric Gauss-Seidel）推进方法和并行计算策略。最后,运用该方法分别对悬停状态下C-T（Caradonna-Tung）旋翼和UH-60A旋翼以及前飞状态下C-T旋翼和SA349/2旋翼的涡流场及气动特性进行了数值模拟,并将数值结果与传统二阶精度格式的计算值进行了对比。结果表明：在计算时间增长10%~20%的前提下,五阶WENO格式能够捕捉到更精确的涡流场特性,反映了五阶WENO格式在计算旋翼非定常涡流场时具有更高的计算精度与更低的数值耗散特性。
Aimed at improving the computational fluid dynamics（CFD）computation accuracy and reducing the numerical dissipation of the vortex flowfield of helicopter rotor,the highly-accurate CFD method based on fifth-order weighted essentially non-oscillatory（WENO）scheme has been established for numerical simulation on the unsteady flowfield of rotors.In this method,the moving-embedded grid technique has been employed in the numerical simulation,the Navier-Stokes equations have been taken as governing equations,and one equation Spalart-Allmaras turbulence model has been employed.In order to improve the computation accuracy of the rotor vortex formation and evolution,the discretization of convective fluxes and the time marching are conducted by Roe-WENO scheme and the highly efficient implicit LU-SGS（Lower-Upper Symmetric Gauss-Seidel）scheme respectively,and the parallel strategy is employed to accelerate the calculation as well.The computation of the left and right flow quantities is based on the fifth-order WENO scheme,which uses the appropriate weights to combine all the candidate stencils to obtain the fifth-order approximation.Finally aerodynamic characteristics and blade-tip vortex of the several rotors（C-T and UH-60 Arotor in hover,C-T rotor in non-lifting forward flight and SA349/2rotor in forward flight）have been simulated by the present method.Comparing numerical results with experimental data and calculated results using the JST scheme and Roe-MUSCL scheme,it is demonstrated that the present method with only 10%~20%increase of computational consumption has high accuracy and low numerical dissipation in simulating the aerodynamic characteristics and blade-tip vortex.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2016年第8期2552-2564,共13页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(11272150)
江苏高校优势学科建设工程基金~~
