BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Improved assessment of the statistical stability of turbulent flow s using extended Orr-Sommerfeld stability analysis - Vilda Markeviciute (U niversity of Cambridge) DTSTART:20220331T093000Z DTEND:20220331T100000Z UID:TALK171200@talks.cam.ac.uk DESCRIPTION:The concept of statistical stability is central to Malkus's 19 56 attempt to predict the mean profile in shear flow turbulence. Here we d iscuss how his original attempt to assess this - an Orr-Sommerfeld analysi s on the mean profile - can be improved by considering a cumulant expansio n of the Navier-Stokes equations. Focusing on the simplest non-trivial clo sure (commonly referred to as CE2) which corresponds to the quasilinearize d Navier-Stokes equations\, we develop an extended Orr-Sommerfeld analysis (EOS) which also incorporates information about the fluctuation field. A more practical version of this  \;- minimally extended Orr-Sommerfeld analysis (mEOS) - is identified and tested on a number of statistically-st eady and therefore statistically stable turbulent channel flows. Beyond th e concept of statistical stability\, this extended stability analysis shou ld also improve the popular approach of mean-flow linear analysis in time- dependent flows by including more information about the underlying flow in its predictions.\nCo-author: Rich R. Kerswell LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR