“…These results significantly extend the preliminary analysis conducted by Zamponi et al. (2020), which was based on the RDT asymptotic solution in (4.1). Likewise, the predictions qualitatively agree with the conclusions drawn by the investigation of the measured turbulent-velocity fluctuations (figure 11 in Zamponi et al.…”
Section: Rapid Distortion Theory Results In Presence Of Porositysupporting
confidence: 86%
“…This evidence is supported by the results of the static pressure measurements on the surface of the porous aerofoil shown in figure 10 in Zamponi et al. (2020). Figure 12.( a ) Representation of the porous NACA-0024 profile featuring the solid middle-plane that prevents the cross-flow between pressure and suction side, the hard-plastic exo-skeleton that preserves the aerofoil shape integrity and the metallic wire mesh that ensures the desired surface roughness.…”
Section: Rapid Distortion Theory Results In Presence Of Porositysupporting
confidence: 73%
“…The RDT calculations are compared with the hot-wire anemometry measurements performed by Zamponi et al. (2020). ( b ) Solid and porous () normalised variances of the streamwise and upwash velocity components computed along the stagnation streamline for .…”
Section: Rapid Distortion Theory Results In Presence Of Porositymentioning
confidence: 99%
“…This hypothesis has been recently addressed by Zamponi et al. (2020), who experimentally investigated the turbulent flow interacting with a thick porous aerofoil by fitting melamine foam into a NACA-0024 profile. Flow field measurements were performed by placing solid and porous aerofoil configurations in the turbulent wake shed by an upstream circular rod.…”
Section: Introductionmentioning
confidence: 99%
“…In the present work, the experimental investigation on the porous NACA-0024 profile performed by Zamponi et al. (2020) is considered as a test case for the analytical model in order to explore this possibility. The RDT calculations are thereby validated through comparison with the velocity measurements.…”
“…These results significantly extend the preliminary analysis conducted by Zamponi et al. (2020), which was based on the RDT asymptotic solution in (4.1). Likewise, the predictions qualitatively agree with the conclusions drawn by the investigation of the measured turbulent-velocity fluctuations (figure 11 in Zamponi et al.…”
Section: Rapid Distortion Theory Results In Presence Of Porositysupporting
confidence: 86%
“…This evidence is supported by the results of the static pressure measurements on the surface of the porous aerofoil shown in figure 10 in Zamponi et al. (2020). Figure 12.( a ) Representation of the porous NACA-0024 profile featuring the solid middle-plane that prevents the cross-flow between pressure and suction side, the hard-plastic exo-skeleton that preserves the aerofoil shape integrity and the metallic wire mesh that ensures the desired surface roughness.…”
Section: Rapid Distortion Theory Results In Presence Of Porositysupporting
confidence: 73%
“…The RDT calculations are compared with the hot-wire anemometry measurements performed by Zamponi et al. (2020). ( b ) Solid and porous () normalised variances of the streamwise and upwash velocity components computed along the stagnation streamline for .…”
Section: Rapid Distortion Theory Results In Presence Of Porositymentioning
confidence: 99%
“…This hypothesis has been recently addressed by Zamponi et al. (2020), who experimentally investigated the turbulent flow interacting with a thick porous aerofoil by fitting melamine foam into a NACA-0024 profile. Flow field measurements were performed by placing solid and porous aerofoil configurations in the turbulent wake shed by an upstream circular rod.…”
Section: Introductionmentioning
confidence: 99%
“…In the present work, the experimental investigation on the porous NACA-0024 profile performed by Zamponi et al. (2020) is considered as a test case for the analytical model in order to explore this possibility. The RDT calculations are thereby validated through comparison with the velocity measurements.…”
The flow field on solid and porous airfoils subjected to turbulence shed by an upstream cylindrical rod and the corresponding far-field noise radiations are studied through particle image velocimetry (PIV) and microphone measurements, respectively. Three different Reynolds numbers based on the rod diameter are considered in a range between 2.7 × 10 4 and 5.4 × 10 4 , and two porous airfoil models are tested to analyze the influence of the design elements of the permeable treatment. A standard proper orthogonal decomposition (POD) algorithm is employed to band filter the different length scales that characterize the turbulent flow, making it feasible to determine which turbulence scales are affected by porosity. The aeroacoustic results indicate that the porous treatment of the wing profile leads to a noise reduction at low frequencies and a noise regeneration at high frequencies due to surface roughness. The investigation on the flow field shows that the main effect of porosity is to mitigate the turbulent kinetic energy in the stagnation region, attenuating the distortion of turbulence interacting with the airfoil surface. The application of the POD algorithm indicates that this effect acts mainly on the largest scales of turbulence.
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