煤烧圆家重点实验宝 3)Probability density Function (x2)=「叭(x4)P()dp(2-3) 4)Reynolds average for turbulent quantity p 三-y whereφ— transient value φ— average value National Lab, of Coal Combustion. HUST pulsing value Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cnNL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 3) Probability Density Function   − e (x0 ,t 0 ) = (x0 ,t 0 )P()d 4) Reynolds average for turbulent quantity     − ' where  ⎯ transient value  ⎯ average value ’⎯ pulsing value (2-4) (2-3)