Abstract
The flow in the wake behind a circular cylinder in a cross-flow at Reynolds number of 4815 was studied both experimentally and via mathematical modeling. The mathematical model was performed as a Large Eddy Simulation (LES), while the experiments were carried out using the time-resolved variant of the Particle Image Velocimetry (PIV) method. Both the simulation and experiment took into account the dynamical aspects of the studied phenomenon, which enabled a detailed validation of the mathematical model. The overall statistical properties of the simulated flow were validated via comparing the time-averaged measured and computed velocity and vorticity fields. To validate the dynamical behavior, the velocity spectra were examined first. Next, the Proper Orthogonal Decomposition (POD) of the spatio-temporal velocity data was performed on both the experimental and numerical data and a comparison of the obtained energetic modes was carried out. All the performed validations have shown a satisfactory agreement between the simulation and the experiment.
Highlights
Two strong trends have been observed in fluid dynamics during the past decade
The measured and modeled flow fields are studied via the means of proper orthogonal decomposition (POD) [13,14,15,16], where we focus on the most energetic coherent flow structures
It might be assumed that a simulation returning results similar to the experiment for all the three steps reflects the real flow dynamics
Summary
Two strong trends have been observed in fluid dynamics during the past decade. First, the increasing available computing power have enabled applications of high-fidelity modeling approaches, such as the large eddy simulation (LES), even to industrial-scale problems [1,2,3]. Improving measurement techniques, e.g. the particle image velocimetry (PIV), provide more and more detailed data on flow dynamics. If any analysis of the system dynamics is performed, it is usually limited to the comparison of turbulence spectra as in [7, 8]. Such a situation follows from the fact that most existing verification and validation methods for fluid flow simulations are derived for the computationally cheaper and better established Reynolds-averaged Navier-Stokes equations (RANS) [9]
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