On the noise reduction of a porous trailing edge applied to an airfoil at lifting condition

Numerical simulations, using a lattice-Boltzmann technique, have been carried out to study the effect of aerodynamic loading and Reynolds number on aeroacoustics porous trailing-edge insert. The airfoil is National Advisory Committee for Aeronautics 0018 with last 20% its chord being replaceable insert based Ni-Cr-Al metal foam mean pore diameter 0.8 mm. modeled as an equivalent fluid region governed by Darcy's law. angle-of-attack set 7.8°, freestream numbers are 2.7 × 105 5.4 105. amount noise reduction produced generally decreases or increased, although far-field directivity remains similar that solid case. Unlike insert, in which sources concentrated at trailing edge, those distributed across medium surface, they promote phase interference causes attenuation. This mechanism realized pressure release process, refers interaction between surface fluctuations both sides edge through medium. It found process strongly present 25% extent, thus upstream segment plays relatively limited role also velocity deficit, enhanced shear stress, lower convection turbulent boundary layer. Nevertheless, since only flow field surrounding affected, overall penalty minor. has cross-flow inside almost negligible investigation due small difference two