Large-eddy simulation of a three-dimensional shear-driven turbulent boundary layer

Abstract

A three-dimensional shear-driven turbulent boundary layer over a flat plate generated by moving a section of the wall in the transverse direction is studied using large-eddy simulations. The configuration is analogous to shear-driven boundary layer experiments on spinning cylinders, except for the absence of curvature effects. The data presented include the time-averaged mean flow, the Reynolds stresses and their budgets, and instantaneous flow visualizations. The near-wall behaviour of the flow, which was not accessible to previous experimental studies, is investigated in detail. The transverse mean velocity profile develops like a Stokes layer, only weakly coupled to the streamwise flow, and is self-similar when scaled with the transverse wall velocity, Ws. The axial skin friction and the turbulent kinetic energy, K, are significantly reduced after the imposition of the transverse shear, due to the disruption of the streaky structures and of the outer-layer vortical structures. The turbulent kinetic energy budget reveals that the decrease in production is responsible for the reduction of K. The flow then adjusts to the perturbation, reaching a quasi-equilibrium three-dimensional collateral state. Following the cessation of the transverse motion, similar phenomena take place again. The flow eventually relaxes back to a two-dimensional equilibrium boundary layer.

Large eddy simulations of Taylor-Couette-Poiseuille flows in a narrow-gap system

“…This behavior is opposite of that found by Jung and Sung 12 for η = 0.5 and N = 0 and 0.429 but in agreement with previous numerical simulations of rotating pipes 37 and 3DTBL over a flat plate. 38 For 1.49 ≤ N ≤ 6.71, the rotor and stator boundary layers exhibit the main characteristics of 2DTBL except for the misalignment of the Reynolds shear stress and mean velocity gradient angles. These two boundary layers have then a more complex behavior in this range of swirl parameters in the narrow-gap case.…”

Direct numerical simulation of a non-equilibrium three-dimensional turbulent boundary layer over a flat plate

“…The relationship between (1.5) and (1.6) will be discussed in § 3.2. In the present flow, the seminal numerical simulation was done by Kannepalli & Piomelli (2000) with the use of a wall-resolved large-eddy simulation (LES). They examined the effect of cross-flow for two different magnitudes of W S /U 0 = 0.3 and 1.0, where Re θ ≈ 1100 in their 3DTBL.…”

“…They demonstrated that a half-power-law dependence in θ z /W s is intrinsically associated with the Stokes layer in which θ z ∼ t 1/2 . Kannepalli & Piomelli (2000) also discussed a possible scaling law of the spanwise skin friction coefficient C f ,z (defined in § 3.1) for W S /U 0 = 1 by comparing with the experimental data of Driver & Johnston (1990) (Re θ = 6000 in a trailing edge of the spinning cylinder). They used a normalization by U e W s /2ρ (see relation (4.1)).…”

Large-eddy simulations for internal combustion engines – a review

“…There has been continued effort is this area for several years (e.g. Kannepalli and Piomelli [45] and Chang et al [46]), but, to date, no significant progress has been made on practical models for CFD applications. Some promising advanced work by Cabot and Moin [47] used RANS models with additional consideration for unsteadiness and 'ejection' events.…”

“…Thus, most LES simulations use one of two approaches for wall boundary conditions: (a) no special treatment of the wall, except for additional grid points (Kannepalli and Piomelli [45]), and (b) wall-layer models essentially the same as used in RANS that have been shown, by Rodi et al [50], to give reasonably good results. For engine applications, the use of wall functions is probably the best approach for the near future.…”