roughness factor

The friction factor for the turbulent flow in pipes is the binary nonlinear function of Reynolds number and relative roughness. Calculating friction factor by implicit Colebrook equation have to use iterative algorithm, which is discommodious.

管内湍动流体摩擦因数是雷诺数和相对粗糙度的二元非线性函数，由Colebrook隐式方程计算摩擦因数要用迭代的方法求解，很不方便。

Roughness of rock joints is a major factor affecting mechanical properties of rock joints.

节理的粗糙性是影响节理力学性质的重要因素.

As far as the single factor is concerned, the optimal level of surface roughness is burnished by sand paper ( 0.045-0.055mm).

就单一因素的影响来看，表面粗糙度的最优水平为采用280～320~（0.045～0.055mm）砂纸打磨；