Plate Silencer

Plate Silencer and Sound Absorption — ANSYS Fluent CFD Simulation

Description

This project presents a CFD simulation of a plate silencer — a device used to absorb unwanted noise across industries from automotive and power generation to mining, subway tunnels, and architectural acoustics. A silencer works by vibrating in response to incoming sound waves; when the silencer's mode shapes match the sound waves, the energy is absorbed, quieting the environment. In this project, you'll model a symmetric silencer with a sinusoidal wavy plate at its center and study how acoustic waves behave as they travel through it, quantifying the silencer's noise-reduction efficiency. Within the Acoustics: Beginner CFD Training Package, this project applies the FW-H model taught earlier to a real noise-control device, opening the applied silencer and sound-absorption cases.

Methodology

The 2D symmetric silencer geometry, with a wavy central plate of 0.015 m wave amplitude, is designed in Design Modeler and meshed with a structured grid of roughly 17,000 elements for the acoustic domain. The Ffowcs-Williams & Hawkings (FW-H) acoustic model is set up, defining the far-field density (1.225 kg/m³), sound speed (340 m/s), and reference acoustic pressure (2×10⁻⁵ Pa), with acoustic sources defined near the inlet to introduce the pressure waves. The simulation must be transient to capture the wave behavior over time. The boundary conditions include a velocity inlet, a pressure outlet, and convective walls with a heat-transfer coefficient, and the setup uses the Realizable k-ε model with enhanced wall treatment and the energy equation.

Analysis

Post-processing produces pressure, velocity, and temperature contours, along with Sound Pressure Level (dB) versus frequency at inlet and outlet receivers and — most importantly — the Transmission Loss diagram, which quantifies how much sound the silencer removes across the frequency range. From these results you can evaluate the silencer's noise-reduction efficiency and understand how the wavy plate absorbs acoustic energy. Noise control is a regulated requirement across the automotive, HVAC, power, and building industries, and the FW-H acoustic workflow built here is the foundation for designing mufflers, exhaust systems, and any noise-attenuating device. By the end of this project, you'll be able to set up a transient FW-H acoustic simulation of a silencer, define acoustic sources and receivers, and interpret the sound-pressure and transmission-loss results that measure noise-reduction performance.