RecrBNC²³⁶²¹³⁺¹ 基本例句 n.接收机⁵⁰收音机;受话器⁵⁰ The factors on the turbulent entrance length were analysed, based on the variable Recr, a new empirical formula was developed for the turbulent entrance length in a pipe flow. 详细分析了管流湍流人口长度的影响因素，提出以临界雷诺数为基础变量的新湍流入口长度经验公式。 cnki