基于非定常CFD的俯仰动导数计算方法

Calculation Method of Pitching Dynamic Derivatives Based on Unsteady CFD Technology

采用基于N-S方程求解的非定常CFD技术,对俯仰动导数数值计算方法进行了研究。研究了时间步长、内迭代次数、强迫运动幅值、减缩频率对俯仰动导数计算结果的影响。计算了动导数标模在不同马赫数下的俯仰动导数,并与实验结果进行了比较。结果表明,时间步长与减缩频率是影响俯仰动导数计算结果的2个重要因素。给出了俯仰动导数数值计算时间步长与减缩频率选取的一般原则。基于非定常CFD技术的俯仰动导数数值计算方法精度较高,与实验结果吻合良好,具有较高的工程应用价值。

Based on solving N-S equations , the numerical prediction method of pitching dynamic derivatives was studied .The effects of transient time-step, inner iterations , forced sinusoidal motion amplitude and reduced frequency on the calculation result of pitching dynamic derivatives were analyzed . Prediction of dynamic derivatives was conducted for the standard model of dynamic derivatives .The result shows that the transient time-step and reduced frequency are the most important factor affecting dynamic derivatives prediction .The general principle of choosing transient time-step and reduced frequency was presented .The calculation method of pitching dynamic derivatives based on unsteady CFD has high accuracy ,and the result accords with the experiment data .The method has practical value .