Defect motion in pattern formation (gliding and climbing, defects annihilation, pinning effects, and pattern reorientation) is analyzed for the first time when a fluid layer heated from below rotates slowly around its vertical axis. This system allows for a continuous change from a (approximately) variational problem (no rotation) to a nonvariational one by increasing the externally applied rotation rate. By a numerical integration of the 3D-hydrodynamic equations, climbing and gliding velocities of defects are determined. A mechanism leading to a reorientation of a parallel roll structure is discussed.

• Received 19 January 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.530