Noise pollution levels are constantly exceeding health safety limits in many Indian cities. Vengat has taken it upon himself to contribute towards reducing the noise made by the vehicles.
As a part of his master thesis, Vengat, supervised by Dr. K. Shanmuga Sundaram, focuses on methods to reduce the noise escaping from mufflers on 350cc internal combustion engines. Here he particularly investigates the effect of introducing a helically divergent tube (see image above) at the end of the muffler.
With the help of the FINE™/Acoustics tutorial on the muffler-wizard, Vengat first analyzed the transmission loss through the system. He observed that the transmission loss reduced with increase in frequencies.
Figure: Acoustic pressure [dB] fields at cuts through the middle of the tube for different increasing frequencies 260 Hz, etc.
After finishing the transmission loss calculation, Vengat moved on to analyzing the difference in the acoustic power, radiated with and without the fitted-muffler. This is called insertion loss. He was able to capture the the insertion-loss for different frequencies as shown in the figure below.
Figure: Sound pressure level attenuation provided by the muffler including sound absorbing material
After successfully calculating the transmission and insertion loss, Vengat has now moved onto calculating the flow induced noise. We wish him all the best and success for his thesis!