S. Gokul
Department of Aerospace Engineering, Indian Institute of Space Science and
Technology, Thiruvananthapuram, Kerala-695547, India
Vagesh D. Narasimhamurthy
GexCon AS, P.O. Box 6015, Postterminalen, 5892 Bergen; Fluids Engineering Division, Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway; Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600 036, India
In plane Couette flow (pCf), the transitional regime is
characterized by oblique laminar-turbulent bands. These large scale patterns are periodic in both streamwise and spanwise directions. In this study, we perform direct numerical simulations (DNS) of pCf undergoing a reverse transition to understand the characteristics of the laminarturbulent bands. The large scale flow vectors near the bands are almost parallel to them due to a considerable spanwise velocity. Transitional pCf is different from its fully turbulent counterpart in certain aspects. Unlike fully turbulent flow, counter-rotating secondary roll cells are absent in the transitional regime. Another major difference is the presence of non-zero off-diagonal components of Reynolds stress tensor in transitional pCf.