Split form ALE discontinuous Galerkin methods with applications to under-resolved turbulent low-Mach number flows

Assessment of a RANS Transition Model with Flapping Foils at Moderate Reynolds Numbers

“…Similar observations are also true for the dynamics of the lower surface boundary layer; although the SA-BCM model predicts the presence of three clockwise-rotating structures, the use of a fully turbulent SA closure does not seem to be able to capture any vorticity ejection into the fluid domain. The higher accuracy resulting from the application of a transition model is made evident upon inspection of the three-dimensional results in [11,12]. The early transition state at the upper surface, with the presence of span-wise homogeneous vortices, seems to be exactly captured by the SA-BCM model.…”

“…Even though an accurate capture of the LEV dynamics, and thus an overall accurate flow description, is thought to be fundamental for precise computation of the forces exerted on the profile, the simulated configuration revealed to be solely dominated by the dynamics of the profile motion rather than the flow structure itself. Such an observation seems to be justified by the small difference in the forces predicted by the two models, even though SA-BCM allowed the derivation of a much more accurate representation of the relevant flow features with respect to the standard SA, especially when compared with the threedimensional results in [11,12]. To demonstrate this, in Table 1 the thrust coefficients derived from the two models are reported as averages realized over five motion periods together with the aforementioned experimental and numerical reference values.…”

“…In particular, several experimental and numerical studies [6][7][8][9][10][11][12] have been carried out at moderate Reynolds numbers, for which transitional effects can be relevant. In this circumstance, the use of the standard, fully turbulent, Reynolds-averaged Navier-Stokes equations (RANS) approach can be erratic, while scale-resolving simulations, namely large eddy simulations (LES) and direct numerical simulations (DNS), are still prohibitively expensive, particularly when a large-scale investigation is required.…”

“…A more detailed description of the parameters will be outlined in the dedicated section (Section 3.1). For the second motion condition, namely high-frequency plunging, the work of Visbal [11] and Krais et al [12] have instead been used as a reference. In [11], a three-dimensional LES analysis was provided for a plunging SD7003 airfoil, considering different values of Reynolds number and motion parameters, together with validation of the experimental results [10].…”

“…A more detailed description will be given in Section 3.2. The work of Krais et al [12] provides additional data, once again derived from scale-resolving simulations (ILES) employing a nodal DG solver adopting the plunging configuration characterized by k = 3.93 and Re = 40,000 defined in [11] as a test case.…”