In order to understand the correct situation in which to use the word affect or effect, the first thing one must do is have a clear understanding of what each word means. 1  Affect is usually used as a verb. It is an action word that means to produce a change in or influence something. 2  Effect is usually used as a noun.
Shear Factor. The distance a point moves due to shear divided by the perpendicular distance of a point from the invariant line.
Hence, the friction factor can be written in a general form as: (3). From this we see that the friction factor of pipes will be the same of their Reynolds number, roughness patterns, and relative roughness are the same. For a smooth pipe, the roughness term is neglected and the magnitude of the friction factor is determined by fluid Reynolds number alone.