The strong multi-longitudinal vortex flow in the AEA-tube is induced by alternating change of the elliptical cross-section, and for the DDIR-tube, the strong multi-longitudinal vortex flow isinduced by the effect of the discrete double-inclined ribs.

• 交叉缩放椭圆管是通过椭圆截面的交叉变化诱导产生强烈的二次流和多纵向涡流，而不连续双斜向内肋管则是通过不连续的双斜向内肋对的作用形成强烈的多纵向涡。