《工程流体力学》本科生教材中关于圆管突缩管的局部阻力系数计算给出的是经验公式，该公式只考虑了突缩比对局部阻力系数的影响，与实际情况有偏差.所以本文采用流体力学理论和数值计算方法分析影响突缩管局部阻力的要素，研究结果表明：突缩管的局部阻力系数与雷诺数和相对粗糙度正相关，为突缩管局部阻力系数公式的校正提供依据.

In the undergraduate textbook of Engineering Fluid Mechanics, the calculation of the local resistance coefficient of the cylindrical pipe with sudden shrinkage is given by the empirical formula, which only considers the influence of sudden shrinkage ratio on the local resistance coefficient, which is deviated from the actual situation. Therefore, in this paper, the factors affecting the local resistance of the pipe are analyzed by fluid mechanics theory and numerical calculation method. The research results show that the local resistance coefficient of the pipe is positively correlated with Reynolds number and relative roughness, which provides a basis for the correction of the local resistance coefficient formula of sudden shrinkage pipe.