Benchmark on the Aerodynamics of a Rectangular 5:1 Cylinder (BARC)

Flows Around Bodies

Underlying Flow Regime 2-15

Evaluation

Comparison of CFD Calculations with Experiments

Bulk parameters

The main flow bulk parameters obtained in the different wind tunnel and numerical studies are reported in Tables 7 and 8: ${\left.t-avg(C_{D})\right.}$ and ${\left.t-avg(C_{L})\right.}$ are the time- and spanwise-averaged drag and lift coefficients per unit length, respectively; ${\left.t-std(C_{L})\right.}$ is the standard deviation of the time variation of the lift coefficient; ${\left.St_{D}=f_{s}D/U\right.}$ is the Strouhal number, where the shedding frequency ${\left.f_{s}\right.}$ is evaluated from the time fluctuations of the lift coefficient or from pressure or velocity time signals (we refer to the single cited articles for more details).

First of all, we remark that at present, among the different wind tunnel tests carried out in the framework of the BARC benchmark, bulk parameters are available only from \citet{schewe2006,schewe2009} and from \citet{bartoli} (only the Strouhal number). In general, several wind tunnel data are available in the literature for the flow around the same body geometry as far as the Strouhal number is concerned and only a few for the mean drag coefficient; these data are also reported in Table 7 for comparison. Conversely, bulk-parameter values computed in 25-36 simulations of the BARC configuration are available. The histograms of the bulk parameters obtained by computational simulations are plotted in Fig. 4. For the sake of brevity, detailed values are not given herein (we refer to the cited papers which may be made available upon request to the interested readers) and only the range of the results obtained in all the simulations carried out in each single contribution is reported in Table 8. The ensemble average over the available data and the standard deviation are also reported in Table 8. The data of the 2D LES in \cite{arslan2011} and of the simulations in \cite{wei} have been excluded from the computation of the ensemble average and of the standard deviations, since they deviate significantly from the other data (see also the discussion below). Moreover, 2D LES is a priori expected to give unreliable results, while the simulations in \cite{wei} are probably affected by a too small size of the computational domain.