Experimental Study on Local Scour and Related Mechanical Effects at River-Crossing Underwater Oil and Gas Pipelines

Table 1

Main physical quantities.

Attributes	Physical quantities	Symbols	Dimensions
Water flow	Flow velocity	u	LT^−1
	Water density	ρ	ML^−3
	Kinetic viscosity	μ	ML^−1·T^−1
Sediment	Median diameter	d50	L
	Sand density	ρs	ML^−3
Pipelines	Diameter	D	L
Other	Gravity		LT^−2
	Distance between the lower wall of the pipeline and the riverbed surface in the physical model	e	L
	Scour depth	S	L