Studying the Effect of Some Surfactants on Drag Reduction of Crude Oil Flow

Table 2

Relative roughness and length of pipes used.

Pipe inside diameter, m	Relative roughness, ε/d	Length of pipe with elbows, m	Length of straight pipe, m
0.0508	0.000885	4.656	3
0.0254	0.001770	2.378	3
0.0191	0.002362	1.687	3