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

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

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....

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.

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