Numerical Investigation of Flow around Two Tandem Identical Trapezoidal Cylinders

Table 2

Characteristics and distinction of the three modes.

Reference volume	Location or relationship	Mode I  ≤ 1	Mode II 2 ≤  ≤ 3	Mode III  ≥ 4	Source
	Downstream cylinder	Negative (−)	Positive (+)	Positive (+)	Figure 3(a)
	Comparison between the two	Up ≈ down	Up > down	Up < down	Figure 3(b)
	EF surface	Negative (−)	Positive (+)	Positive (+)	Figure 6(b)
	FG surface		Minimum		Figure 6(b)
Time-average streamwise velocity	Center line between the two	U-shaped	S-shaped	S-shaped	Figure 7(a)
Flow visualization image	The two cylinders				Figure 9
Names of the three modes		Extended-body regime	Reattachment regime	Binary regime

Note: () was the location of the stationary point.