SINUSOIDAL WAVY CHANNELS WITH TAYLOR-GOERTLER VORTICES

In the concave part of sinusoidal wavy ducts, a flow instability can be observed, leading to longitudinal vortices comparable to the Goertler instability at concave walls or the Dean instability in tube flows. Near-wall flow phenomena are visualized by the visualization of the local mass transfer. The pressure losses are evaluated in a sinusoidal wavy duct with constant wavelength lambda/a, amplitude of the wavy wall a = 1.825 mm, duct width B = 150 mm, and duct length L = 400 mm for various duct heights s and a range of Reynolds numbers. A stability diagram describes the existing range of longitudinal vortices. It is shown that the wavelength lambda(v) of the vortices changes significantly depending on the spacing of the duct.