Velocity and wall-shear-stress measurements of internal vortex flows in a two-sided lid-driven cavity

The Newtonian fluid flour in a two-sided lid-driven cavity is investigated experimentally. The motion is driven by two independently rotating cylinder s forming two facing walls of the cavity. At low Reynolds numbers the flow is two-dimensional, apart from end-wall effects. It becomes three-dimension al via a pitchfork bifurcation at a first critical Reynolds number, and a s teady cellular structure appears. At a second critical Reynolds number this three-dimensional flow becomes time-dependent through a Hopf bifurcation. Both transitions are investigated by laser-Doppler velocimetry (LDV) and ho t-film anemometry (HFA).