Assessment of Wall-Functions k-e Turbulence Models for the Prediction of the Wall Heat Flux in Rocket Combustion Chambers

An efficient modeling framework for wall heat flux prediction in rocket combustion chambers using non adiabatic flamelets and wall-functions

“…In order to save computational resources in view of 3D simulations on complex geometries, wall functions are introduced for turbulent boundary layer modeling. The latter generally prescribe algebraic boundary conditions for mean turbulent quantities based on flow quantities far from the wall [13,25]. According to the standard wall function approach (Launder and Spalding [10]) the last computational node before the wall should fall within the outer layer of a turbulent boundary layer, in order to patch the outer flow solution with the universal velocity and temperature profiles [59,10,12].…”

“…and ν + = ν t /ν w , where T τ = q w /(ρ w C p,w u τ ) is the skin friction temperature while ∆y P is the distance between the last grid node before the wall, denoted by the subscript P , and the wall, denoted by the subscript w. In order to avoid singularities in the definition of u τ , caused by wall shear stress vanishing at re-attachment and separating points [61], Launder and Spalding [62] proposed the use of the local turbulent kinetic energy, k P , as a characteristic turbulent velocity scale. Based on this assumption the skin friction velocity is usually retrieved as [63,25]…”

UQ eSpace

“…Early models of wall function boundary conditions were established with reference to the analysis of flat plates, pipes, and channels examined by Millikan (1938), Tennekes and Lumley (1972). While the analysis revolves mainly around low-speed incompressible fluids, the lawof-the-wall was well presented (Sondak and Pletcher (1995), Vance (2005), Fico, Cutrone, and Battista (2008)). When dealing with high-velocity compressible flows, it was typical to employ an extension of the classic incompressible and adiabatic formula, which considers the fluctuation of the density.…”