A critical evaluation of two-equation models for near wall turbulenceA basic theoretical and computational study of two-equation models for near-wall turbulent flows was conducted. Two major problems established for the K-epsilon model are discussed, the lack of natural boundary conditions for the dissipation rate and the appearance of higher-order correlations in the balance of terms for the dissipation rate at the wall. The K-omega equation is shown to have two problems also: an exact viscous term is missing, and the destruction of the dissipation term is not properly damped near the wall. A new K-tau model (where tau = 1/omega is the turbulent time scale) was developed by inclusion of the exact viscous term, and by introduction of new wall damping functions with improved asymptotic behavior. A preliminary test of the new model yields improved predictions for the flat-plate turbulent boundary layer.
Document ID
19900051580
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Speziale, Charles G. (NASA Langley Research Center Hampton, VA, United States)
Anderson, E. Clay (NASA Langley Research Center Hampton, VA, United States)
Abid, Ridha (Vigyan Research Associates, Inc. Hampton, VA, United States)