Comparison of large eddy simulation and Reynolds-averaged Navier–Stokes evaluations with experimental tests on U-bend duct geometry

Abstract

The correct prediction of the flow field is of crucial importance to drive numerical optimization to a real improvement of a design. For this purpose, different numerical approaches can be used to study the fluid dynamics characteristics and the performance of the design. In particular, in the present work the Reynolds-averaged Navier–Stokes and large eddy simulation approach are compared for an internal aerodynamic application. The obtained solutions are validated against experiments through a quantitative and qualitative comparison, i.e. pressure measurements and particle image velocimetry flow visualizations, respectively.

Cad-Based Adaptive Shape Parametrisation for Aerodynamic Shape Optimisation

“…However height and length of the separation region are underestimated. Similar behavior is also noted in the RANS-based results of Alessi et al [2]. Figure 10 shows a good match between STAMPS and LES for the counter-rotating Dean vortices at the 90 • turn region, only small discrepancies near the inner wall separation region can be observed.…”

“…6b. The comparison of the simulated velocity field and experimental results by Coletti et al [6], the Large Eddy Simulation results by Alessi et al [2] and the STAMPS results is shown in Fig. 9 for the symmetric mid plane (Z/D h ).…”

“…The numerical results obtained using STAMPS are compared with the computational and experimental ones performed by Coletti et al [6,2] for the same Reynolds number Re = 43830. In their experimental work, the inlet leg with 23.3D h long is used to guarantee a fully developed flow at the location of the circular bend.…”

Adjoint shape optimization coupled with LES-adapted RANS of a U-bend duct for pressure loss reduction

“…The same behaviour is highlighted on the outer-wall at the end of the bend. Similar conclusions can be drawn for the comparison of the initial geometry [40].…”

“…However, a recirculation bubble, not detected by the RANS evaluation, is still present inside the design as revealed by the experimental validation through Particle Image Velocimetry (PIV) [39]. On the other hand, simulations using LES could replicate with high accuracy the experimental findings [40]. To further improve the U-bend design, a LES based approach is thus inevitable.…”