Fluid-Elastic Instability Tests on Parallel Triangular Tube Bundles with Different Mass Ratio Values under Increasing and Decreasing Flow Velocities

Table 2

Summary of fluid-elastic instability results.

	Increasing		Decreasing
	In-line direction	Transverse direction	In-line direction	Transverse direction
Aluminum tube
(m/s)	0.782	0.782	0.485	0.485
	8.036	8.036	4.991	4.991
	0.832	0.377	1.023	0.328
calculated for this criterion	8.810	13.088	4.935	8.715
Stainless steel tube
(m/s)	1.140	1.140	0.706	0.706
	11.439	11.439	7.089	7.089
	0.923	0.617	0.456	0.544
calculated for this criterion	11.907	14.563	10.498	9.611