Noise Source Analysis of a Rod–Airfoil Configuration Using Unstructured Large-Eddy Simulation

Giret, Jean-Christophe; Sengissen, Alois; Moreau, Stéphane; Sanjosé, Marlène; Jouhaud, Jean-Christophe

doi:10.2514/1.j053371

Cited by 62 publications

(41 citation statements)

References 49 publications

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“…the mean streamwise velocity is at a minimum on the center-line, a very large discrepancy in the mean velocity is observed. Agrawal & Sharma (2014) are suspicious of the experimental mean velocity data at x/c = −0.87 because the velocity deficit in the wake is expected to reduce with distance away from the rod (Agrawal & Sharma 2014;Giret et al 2015). This behaviour can be identified from the present simulation by comparing the mean streamwise velocity Compared with the experimental data, the r.m.s.…”

Section: Validationmentioning

confidence: 61%

“…The increasing L, followed by the weakening interaction between the turbulent wake and airfoil, is also consistent with the pressure distributions on the airfoil surface tending to be identical. In figure 10(b), the present mean pressure distributions on the airfoil surface are also compared with the experimental data from ECL and the LES results of Giret et al (2015). It can be seen that the calculated solutions for the rod-airfoil configuration with L/d = 10 are very close to the LES results of Giret et al (2015), however, a large gap between the numerical results displayed and the experimental data can be seen.…”

Section: Validationmentioning

confidence: 71%

“…Yet, the two numerical solutions are close to each other, with relatively obvious differences near the center-line, indicating that a relatively higher level of streamwise fluctuating velocity is predicted by the present simulation near the center-line at x/c = −0.87. Since different methods and meshes are adopted, a dispersion of the numerical fluctuating velocity can be observed near the center-line (Giret et al 2015).…”

Section: Validationmentioning

confidence: 99%

“…An illustration of the force behaviour of the rod-airfoil configuration is given by the distribution of the mean pressure on the surface of the cylinder and airfoil, shown in figure 10(a,b), respectively. As shown in figure 10(a), the airfoil behind the cylinder leads to the pressure increase in the base Here, the experimental data from Apelt & West (1975) and Szepessy & Bearman (1992) are measured for the circular cylinder with Re d = 4 × 10 4 ; the experimental data from ECL and the LES results of Giret et al (2015) are obtained for the rod-airfoil configuration with L/d = 10.…”

Section: Validationmentioning

confidence: 99%

“…Casalino, Jacob & Roger 2003;Jacob et al 2005), the large eddy simulation method (LES) (e.g. Casalino et al 2003;Magagnato, Sorgüven & Gabi 2003;Boudet et al 2005;Jacob et al 2005;Greschner et al 2008;Agrawal & Sharma 2014;Giret et al 2015) and the detached eddy simulation method (DES) (e.g. Creschner et al 2004;Caraeni et al 2007;Gerolymos & Vallet 2007;Greschner et al 2008).…”

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confidence: 99%

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Numerical investigation on body-wake flow interaction over rod–airfoil configuration

et al. 2015

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Numerical investigations of body-wake interactions were carried out by simulating the flow over a rod-airfoil configuration using high-order implicit large eddy simulation (HILES) for the incoming velocity U ∞ = 72 m s −1 and a Reynolds number based on the airfoil chord 4.8 × 10 5 . The flow over five different rod-airfoil configurations with different distances of L/d = 2, 4, 6, 8 and 10, respectively, were calculated for the analysis of body-wake interaction phenomena. Various fundamental mechanisms dictating the intricate flow phenomena including force varying regulation, flow structures and flow patterns in the interaction region, turbulent fluctuations and their suppression, noise radiation and fluid resonant oscillation, have been studied systematically. Due to the airfoil downstream, a relatively higher base pressure is exerted on the surface of the cylinder upstream, and the pressure fluctuation on the surface of the rod-airfoil configuration with L/d = 2 is significantly suppressed, resulting in a reduction of the fluctuating lift. Following the distance between the cylinder and airfoil strongly decreases, Kármán-street shedding is suppressed due to the blocking effect. The flow in this interaction region has two opposite tendencies: the influence of the airfoil on the steady flow is to accelerate it and the counter-rotating vortices connecting with the leading edge of the airfoil tend to slow the flow down. There may be two flow patterns associated with the interference region, i.e. the Kármán-street suppressing mode and the Kármán-street shedding mode. The primary vortex shedding behind the cylinder upstream, and the shedding wake impingement onto the airfoil downstream, play a dominant role in the production of turbulent fluctuations. When primary vortex shedding is suppressed, the intensity of impingement is weakened, resulting in a significant suppression of the turbulent fluctuations. Due to these factors, a special broadband noise without a manifestly distinguishable peak is radiated by the rod-airfoil configuration with L/d = 2. The fluid resonant oscillation within the flow interaction between the turbulent wake and the bodies was further investigated by adopting a feedback model, which confirmed that the effect of fluid resonant oscillation becomes stronger when L/d = 6 and 10.The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to the body-wake interaction.

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Section: Validationmentioning

confidence: 61%

Section: Validationmentioning

confidence: 71%

Section: Validationmentioning

confidence: 99%