Instantaneous streamwise velocity field in the AR = 10, Retau=180 case, with walls made transparent for clarity. Green and orange are low and high velocities. Figure extracted from Vinuesa et al., Pys. Rev. Fluids 3 (2018).
References:
R. Vinuesa, P. Schlatter and H. M. Nagib. Secondary flow in turbulent ducts with increasing aspect ratio, Phys. Rev. Fluids 3, 054606 (2018).
R. Vinuesa, A Noorani, A. Lozano-Duran, G. K. El Khoury, P. Schlatter, P. F. Fischer and H. M. Nagib. Aspect ratio effects in turbulent duct flows studied through direct numerical simulation. J. Turbul., 15, 677-706 (2014).
R. Vinuesa, C. Prus, P. Schlatter and H. M. Nagib. Convergence of numerical simulations of turbulent wall-bounded flows and mean cross-flow structure of rectangular ducts. Meccanica, 51, 3025-3042 (2016).
R. Vinuesa, P. Schlatter and H. M. Nagib. On minimum aspect ratio for duct flow facilities and the role of side walls in generating secondary flows. J. Turbul., 16, 588-606 (2015).