[Back]

B. Scheichl: 
''Gross separation approaching a blunt trailing edge as the turbulence intensity increases''; 
Philosophical Transactions of The Royal Society A (invited), 372 / Theme Issue ''Stability, separation and close-body interactions'' (2014), 2020; 20140001-1 - 20140001-18.

@article{scheichl14:20140001-1[TUW-227608],
    author = {Scheichl, Bernhard},
    title = {Gross separation approaching a blunt trailing edge as the turbulence intensity increases},
    journal = {Philosophical Transactions of The Royal Society A},
    year = {2014},
    volume = {372 / Theme Issue ''Stability, separation and close-body interactions''},
    number = {2020},
    pages = {20140001-1--20140001-18},
    url = {http://publik.tuwien.ac.at/files/PubDat_227608.pdf},
    doi = {10.1098/rsta.2014.0001},
    keywords = {bluff-body flows, interactive boundary layers, massive separation, Rayleigh stage, triple deck, turbulence},
    abstract = {\par
 A novel rational description of incompressible two-dimensional time-mean turbulent boundary layer flow separating from a bluff body at an arbitrarily large globally formed Reynolds number, Re, is devised. Partly in contrast to and partly complementing previous approaches, it predicts a pronounced delay of massive separation as the turbulence intensity level increases. This is bounded from above by a weakly decaying Re-dependent gauge function (hence the boundary layer approximation stays intact locally) and thus the finite level characterising fully developed turbulence. However, it by far exceeds the moderate level found in a preceding study which copes with the associated moderate delay of separation. Thus, the present analysis bridges this self-consistent and another forerunner theory, proposing extremely retarded separation by anticipating a fully attached external potential flow. Specifically, it is shown upon formulation of a respective distinguished limit at which rate the separation point and the attached-flow trailing edge collapse as Re -{\textgreater} oo and how on a short streamwise scale the typical small velocity deficit in the core region of the incident boundary layer evolves to a large one. Hence, at its base the separating velocity profile varies generically with the one-third power of the wall distance, and the classical triple-deck problem describing local viscous/inviscid interaction crucial for moderately retarded separation is superseded by a Rayleigh problem, governing separation of that core layer. Its targeted solution proves vital for understanding the separation process more close to the wall. Most important, the analysis does not resort to any specific turbulence closure. A first comparison with the available experimentally found positions of separation for the canonical flow past a circular cylinder is encouraging. \par
},
    note = {invited}
}



Created from the Publication Database of the Vienna University of Technology.