Application of Generalized Wall Function for Complex Turbulent Flows

Abstract

Abstract. This paper describes a generalized wall function for threedimensional turbulent boundary layer flows. Since the formulation is valid for various pressure gradients including those associated with zero skin friction, it can be applied to wall bounded complex flows with acceleration, deceleration and recirculation. This generalized wall function is extended to the whole surface layer (or inner layer), covering the viscous sublayer, buffer layer and inertial sublayer; therefore, it is a unified wall function. This 'unified' feature is particularly useful for computational fluid dynamics (CFD) to deal with flows with complex geometries, because it allows a flexible grid resolution near the wall to provide accurate wall boundary conditions. This paper also describes a systematic procedure for implementing the wall function in a general CFD code. Finally, a few examples of complex turbulent flows are presented to show the performance of the generalized wall function.

Evaluation of non-uniform cooling effects for air-cooled forgings

“…Adverse gradients are created by cross-flows [38], and, importantly, interact strongly with the local flows behind cylinders. Very recently Shih et al [39] have developed a generalised wall function, for both types of pressure gradient. Alternatively, some codes (e.g.…”

An analytical wall-function for turbulent flows and heat transfer over rough walls

“…This approach showed good performance in several boundary layer flows including transonic, supersonic and hypersonic flows. More recently, Shih et al (2003) employed a combined velocity scale composed of a friction velocity and a pressure gradient. Although the logarithmic velocity distribution was still used, they obtained successful results for flows with a separation and an adverse pressure gradient according to the use of the combined velocity scale.…”

Modeling of Internal Reacting Flows and External Static Stall Flows Using RANS and PRNS

“…A previous experience in the RANS simulation showed that the generalized wall function was able to catch the near wall behavior of turbulent mean profile toward the wall. However, the RANS without wall function needs a fine grid resolution near the wall (see [10]). In our PRNS simulation of NACA0012 airfoil, the grid near the wall is quite fine.…”

“…Here we just report what we have found so far for the wall bounded internal and external flows. In the internal flow simulations using NCC code (see [1] and the present paper), a generalized wall function [10] was used to avoid the immediate vicinity of the wall (as a common practice in LES type of simulations). In our previous PRNS simulation of pipe flows at different Reynolds numbers, the results with RCP=0.38 were well compared with the available experimental data from the center line all the way toward the wall.…”

“…18 Contour of hydrogen mass fraction near injection points (PRNS) Fig. 19 A section of numerical grid of NACA0012 subscale model is (10), which is evolved from the above RANS model. The flow field for each angle of attack was fully developed after 4000 time steps as evidenced by the history of the loads (i.e., the integrated lift, drag and moment, e.g., see Figs.…”