The importance of controlling the upstream body wake in tandem cylinders system for noise reduction

Abstract

This work numerically investigates the importance of controlling the wake of upstream body in the tandem cylinders aiming at aerodynamics noise reduction. The two-dimensional unsteady Reynolds-averaged Navier-Stokes approach with the k-o turbulence model and Ffowcs Williams-Hawkings method are employed to simulate the flow field and the aerodynamics noise, respectively. The flow in the porous media is calculated by a volume-averaged model. Analogy to the mass-spring-damper system, one preliminary model is proposed to reveal the key role of stabilizing the upstream body wake. The simulations of different porous materials coating designs are implemented to corroborate the model and provide more details of flow modification by porous materials coating. Results indicate that the porous materials coating designed on the upstream cylinder can decrease the wake impingement on the downstream cylinder via suppressing the vortex shedding. Subsequently, not only the tonal noise but also the broadband noise level of tandem system can be reduced. It is also clarified that the effects of downstream cylinder absorption and downstream cylinder wake control by porous materials coating is not comparable with the upstream cylinder wake control. The present study gives a new idea to flow control and noise reduction of the multibody systems considering efficiency and economy.

Effects of Blowing Location on Aeroacoustics of the Flow over a Circular Cylinder

“…As it was mentioned earlier, to predict the noise in this study, the two-dimensional solver with turbulence model is considered the same as previous studies. Due to the lower computational cost of two-dimensional models compared to 3D models (Cox et al 1998, Khorrami et al 2007, Liu et al 2015, Liu et al 2018and Abbasi and Souri 2021b) and weaker noise estimation of the two-dimensional models, they are still more favorable for researchers (Ganta et al 2019). In Fig.…”