X型热线探头的方向系数及其对湍流测量的影响

热线的方向系数对湍流测量精度很大的影响。对于Ｘ型探头，热线的方向系语在校准曲线里，这给热线校准带来一定的困难。本文提出一种同时求出Ｘ探头的热线方向系数和校准曲线的逐步逼近法，并测得两根热线的方向系数为０．３０７和０．２５８，此值单针探头的方向系数不同，在三角形钝体尾流的测量中，本文还评估了方向系数对雷诺应力测量值的影响。实验表明，如果不考虑方向系数，最大误差可达１０％。

Directional Sensitivity of X-probe and its Influence on the Turbulence Measurements

The directional sensitivity of hot-wire effects the measurement accuracy. It is difficult to calibrate an X-probe,since the directional coefficient is coupled into the calibration curve. This paper describes a succesive approximation technique for obtaining the directional coefficients of an X-probe and its calibration curve. An evaluation of the effect of the directional sensitivity on the turbulence measurement has been made. It is shown that neglecting the directional coefficient yields a maximum error 10% in the measurement of Reynolds stress.