Experimental observation of the quasiperiodic modes in a rotating Couette system

We experimentally observed the spatiotemporal velocity field of modulated waves (quasiperiodic mode) in a Couette-Taylor system for Reynolds number 9≤R/${\mathit{R}}_{\mathit{c}}$≤28. A power spectrum averaged over four axial wavelengths showed clear evidence of the coexistence of two quasiperiodic modes for a wide range of Reynolds number and the first azimuthal wave mode disappeared at R/${\mathit{R}}_{\mathit{c}}$≊18.