Zonal large-eddy simulation of a tip leakage flow

Abstract

International audienceno abstrac

Wavelet Analysis of a Blade Tip-Leakage Flow

“…In both the experiment [6,7] and the simulation [8,9], a broad hump was observed in near-field spectra at the airfoil tip, around 1.3 kHz. Moreover, its frequency range, which extends over more than two octave bands, is located within that of the tip-leakage noise (0.7-7 kHz), which makes it particularly interesting.…”

“…This simplicity enabled Jacob et al [6,7] to carry out a detailed experimental characterization, on both aerodynamics and acoustics. A zonal large-eddy simulation was also performed on the same configuration and compared very favorably to the experiment, as shown by Boudet et al [8,9] on mean flow, Reynolds stresses, and spectra. In both the experiment and the simulation, a broad hump was observed on pressure spectra at tip, around 1.3 kHz, within the frequency range in which the tip leakage has a significant noise contribution (0.7-7 kHz).…”

“…Because the simulation was initiated before the second test campaign, the original angle of attack (15 deg) was chosen. After convergence, results were stored every 3000 iterations over more than 10 ⋅ c∕U 0 (instead of 6 ⋅ c∕U 0 in [8]), and flow statistics were computed on the fly.…”

“…The total number of grid points is about 150 × 10 6 , distributed over 524 structured blocks for parallel computing. More details about the computation and its validation against experimental data can be found in [8,9].…”

Improved vortex method for large-eddy simulation inflow generation

“…Large-eddy simulation (LES) is becoming more and more attractive, owing to its explicit description of largescale unsteady turbulent motions and the development of sufficient computing power. LES inflow conditions are of great importance as the flow state within the domain of interest is strongly dependent on the inlet conditions, especially for turbulent flows at high turbulent Reynolds numbers [2,3,4,5]. In general, the requirements for LES inlet conditions are: (1) being stochastically fluctuating, (2) being spatially and temporally correlated, (3) being qualified by turbulence criteria and (4) being easy to implement.…”