Description

In this project, the airflow Acoustics over Cylinders in Different Positions (LES) has been simulated, and the simulation results have been investigated using ANSYS Fluent software. We perform this CFD project and investigate it by CFD analysis.

Acoustics is a science that deals with the study of mechanical waves in gases, liquids, and solids, including vibration, sound, ultrasound, and infrasound. It concerns production, control, transmission, reception, and sound effects.

Structured mesh in ICEM is modeled. The number of elements in each file is about 2000000. There is a Boundary layer around cylinders.

Also, due to the nature of the present problem, the transient solver has been enabled.

Acoustic CFD Simulation Methodology

This acoustic project simulates sound pressure waves around cylinders in 4 different positions (4 cases) using Ansys Fluent software.

In general, sound waves within a fluid are caused by vibrations and reciprocating movements of the fluid layers. For example, when a layer of air moves forward in a certain direction, the next fluid layer pushes itself forward, and the layer returns to its original position.

These reciprocating movements of the air layers must continue until the energy within the airflow is depleted. The sound is produced if this number of reciprocating movements reaches more than 16 times per second.

Definitive density is equivalent to air density, i.e., 1.225 kg / m3, air velocity is 69.2 m/s, and the LES smagorinsky model simulates flow turbulence.

Also, Ffowcs-Williams & Hawking’s equations are used to model acoustic. Moreover, the SST k-omega model is used to solve turbulent fluid equations.

Acoustic CFD Simulation Conclusion

At the end of the solution process, two-dimensional contours related to the pressure at different configurations are obtained. As can be seen, Sound Pressure Level plots of different points in geometry are represented.

The exact coordinate of points is as below:

Down point (0   -0.15m   0)

First point (0.4   0   0)

Second point (0.7   0   0)

The distance between the center of circles in the X and Y direction is 100mm.

As a result, it was obtained that the sound pressure level is higher closer to the cylinder.