三次样条插值法影响流场测试精度的研究

Study on the Influence of Cubic Spline Interpolation Methodon the Accuracy of Flow Field Measurement

目前处理五孔探针数据时采用的方法有线性插值法、最小二乘法等。对于相同的测试数据,采用不同插值方法所得到的结果存在差别。为了提高精度,通过理论分析,在这些方法的基础上提出了三次样条插值法。该方法将各标定数据点拟合为抛物线,从而使拟合曲线在非标定点上更接近真实曲线,同时拟合曲线在经过标定点时不发生偏离。为检验方法的合理性,对各种方法做了对比实验。实验结果显示,三次样条拟合曲线更贴近校准曲线。此方法有更广泛的适用性,能够为五孔探针流场测试结果精度的提高起到较大帮助。

At present,linear interpolation method and least square method are used to process five-hole probe data.For the same test data,the results obtained by different interpolation methods are different.In order to improve the accuracy,a cubic spline interpolation method is proposed on the basis of theoretical analysis.In this method,the calibration data points are fitted to parabola,so that the fitting curve is closer to the real curve at the non-calibration point,and the fitting curve does not deviate from the real curve when it passes through the calibration point.In order to test the rationality of the method,this paper makes a comparative experiment on various methods.The experimental results show that the cubic spline fitting curve is closer to the calibration curve.This method has a wider applicability and can greatly improve the accuracy of the five-hole probe flow field measurement results.