温度场内尺度估算方法的研究

STUDY OF ESTIMATING INNER-SCALE OF TEMPERATURE FIELD

用三维超声风速计测量了合肥地区风速脉动和温度脉动数据,从Kolmogorov的4/5定律估算湍流动能耗散率ε,从Yaglom的4/3定律估算温度方差耗散率ε_θ,指出现有文献提供的公式不适合计算温度场的内尺度.提出了一种温度场内尺度计算公式,式中含有温度方差耗散率ε_θ,得到的内尺度大小正确反映了与_n^2强弱的对应关系.

The three velocity components and air temperature were measured using a triaxial ultrasonic anemometer in Hefei region of China. The mean dissipation rates of turbulent kinetic energy ε and 1/2 temperature variance εθ have been estimated by Kolmogorov＇s ‘four-fifths＇ law and Yaglom＇s ‘four-thirds＇ law, respectively. It is pointed that the traditional method is not suitable for estimating inner scale of temperature field. A new relation between the inner scale of temperature field and 1/2 temperature variance εθ is presented. The results of estimating inner scale by the new proposed method perfectly show that strong turbulence has small inner scales and weak turbulence larger inner scales.