基于N-S方程的翼型结冰数值模拟

为了研究结冰对翼型气动性能的影响，采用计算流体力学的方法对NACA0012翼型前缘的结冰进行了预测。在流场计算中，对二维可压粘流的时均N-S方程进行离散求解；采用四步龙格一库塔法求解水滴轨迹运动方程；建立了对应于霜冰和光冰的冰增长模型并假定冰沿着与当地翼型表面法向一致的方向增长来预测结冰的形状。分析了网格数和冰层时间步长对最终冰形的影响和结冰对翼型气动性能的影响，最后将计算的结果与文献中的实验值和计算值进行比较，结果一致。

A Better Numerical Simulation of Ice Accretion on Airfoil

Although the numerical simulation method of Guy Fortin et al~([7,8]) for computing ice accretion on airfoil has taken viscosity into consideration, it is, in our opinion, not the best way to deal with viscosity. We propose solving 2D compressible N-S equations as a better numerical simulation method. We calculate the flow field by solving the 2D compressible N-S equations with Jameson's central finite volume method. We use 4-order Runge-Kutta method to solve the droplet trajectory equation. The forms of ice are different due to different meteorological conditions; we so establish the ice accretion model as to simulate accurately ice shape. We determine ice shape on the assumption that ice grows in the direction normal to the local surface. We applied our method to the prediction of ice accretion on NACA 0012 airfoil. The comparison of our calculated results with the calculated and test results in Refs. 7, 8, and 9 shows preliminarily that our numerical simulation results are in better agreement with test data than the numerical simulation results in Refs. 7, 8, and 9. Painstaking analysis of our numerical simulation results led us to the two following findings: (1) the right finess of grid gives the best numerical simulation results of ice accretion; the results become worse with either finer or coarser grid; (2) the smaller the ice time step, the more accurate is the ice shape.