  The present letter explains the synergetic effect of wall-slip,
compressibility, and thixotropy in a pressurized flow startup operation of
various structured fluids. Opposite to the intuition, experimental and
numerical simulations suggest that the wall-slip (adhesive failure) is
facilitating gel degradation (cohesive failure), revealing a new flow-startup
mechanism. The thixotropic rheological model includes structural degradation
kinetics at the bulk. Whereas, a static slip-based model addresses the
near-wall phenomenon. The near-wall transient variations in axial velocity or
strain evolution, and the initial pressure propagation mechanism along the axis
of the circular pipe explain the essence of the aforementioned synergy.
