3D Self-Sustaining Processes in Shear Flows with and without Surface Waves

Add to your list(s) Download to your calendar using vCal

• Greg Chini (University of New Hampshire)
• Monday 19 October 2015, 13:00-14:00
• MR5, Centre for Mathematical Sciences.

If you have a question about this talk, please contact Doris Allen.

Surface waves modify the fluid dynamics of the upper ocean not only through wave breaking but also through phase-averaged effects involving the surface-wave Stokes drift velocity. Chief among these rectified effects is the generation of a convective flow known as Langmuir circulation (or ``Langmuir turbulence”). Like stress-driven turbulence in the absence of surface waves, Langmuir turbulence is characterized by streamwise-oriented quasi-coherent roll vortices and streamwise streaks associated with spanwise variations in the streamwise flow. To elucidate the fundamental differences between wave-free (shear) and wave-catalyzed (Langmuir) turbulence, two separate asymptotic theories are developed in parallel. First, a large Reynolds number analysis of the Navier—Stokes equations that describes a self-sustaining process (SSP) operative in linearly stable wall-bounded shear flows is recounted. This theory is contrasted with that emerging from an asymptotic reduction in the strong wave-forcing limit of the Craik—Leibovich (CL) equations governing Langmuir turbulence. The comparative analysis reveals important structural and dynamical differences between the SSPs in shear flows with and without surface waves and lends further support to the view that Langmuir turbulence in the upper ocean is a distinct turbulence regime.

This talk is part of the Quantitative Climate and Environmental Science Seminars series.

This talk is included in these lists:

• All CMS events
• All Talks (aka the CURE list)
• CMS Events
• Cambridge Environment
• Climate Science Seminars within Cambridge
• DAMTP Fluids Talks
• DAMTP info aggregator
• Featured lists
• Interested Talks
• MR5, Centre for Mathematical Sciences
• Quantitative Climate and Environmental Science Seminars
• Queens' College Politics Society
• Talks related to atmosphere and ocean dynamics and climate science
• bld31
• ps635

Note that ex-directory lists are not shown.