71th Annual Meeting of the APS Division of Fluid Dynamics (November 18, 2018 — November 20, 2018)

V0021: Symbiosis of quasi-streamwise vortices and low-speed streaks in laminarescent boundary layers

Authors

• Jean Santiago, University of Puerto Rico at Mayaguez, PR, USA
• Guillermo Araya, University of Puerto Rico at Mayaguez, PR, USA
• Guillermo Marin, Barcelona Supercomputing Center, Barcelona, Spain
• Fernando Cucchietti, Barcelona Supercomputing Center, Barcelona, Spain

DOI: https://doi.org/10.1103/APS.DFD.2018.GFM.V0021

High spatial/temporal resolution Direct Numerical Simulation (DNS) of a spatially-developing turbulent boundary layer subject to a very strong favorable pressure gradient (FPG) is performed, by imposing an acceleration parameter of K = 4x10E-6. The strong flow acceleration provokes “quasi-laminarization” since there are significant enduring turbulence intensities and Reynolds stresses in the FPG zone, therefore, the flow is not completely laminar. An important symbiosis between quasi-streamwise vortices and low-speed streaks (or regeneration cycle) has been observed in the FPG zone (Araya & Rodriguez, J. of Visualization, 21, pp. 191-202, 2018). It has been hypothesized that this interaction is the main responsible for “residual turbulence production”, keeping the flow “alive” or laminarescent.