CETA Faculty Member and Alumni Publish Mechanical Engineering and Acoustics Research

The College of Engineering, Technology, and Architecture (CETA) prides itself on the unique opportunity students have in pursuing research related to their majors with the College’s knowledgeable faculty.

Since joining the University in 2016, assistant professor of mechanical engineering Paul Slaboch has worked with many students studying mechanical engineering and acoustical engineering and music on research related to aeroacoustics, experimental fluid mechanics, turbomachinery flows, and aircraft wake turbulence. Two areas of research were recently published.

First, Slaboch collaborated with CETA alumni Sophie Kaye ’19 and Ethan Casavant ’19 while they were undergraduate students on aeroacoustics research. The research, entitled “Low Frequency Acoustic Absorption of 3D Printed Cylinders,” was published on July 1 in the ASME Journal of Vibration and Acoustics, which is a major accomplishment for the students especially as undergraduate research generally only appears in conference publications. Read the paper here. 

Abstract: Attenuating low frequency sound is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. The present study determines the effect of varied outer diameter and outer spacing on the 200-1600 Hz acoustic absorption of additively manufactured arrays of hollow cylinders. Samples were tested in a 100 mm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any parameter can be assessed individually. It was found that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low frequency noise that would otherwise disturb listeners.

Second, Slaboch collaborated with recent CETA graduates Aikaterini Stylianides ’20 and Reagan Johnson ’20 on computational acoustics analysis as an extension of his work with NASA Glenn Research Center from last summer. The research, entitled “Effects of Mean Flow on Supersonic Inlet Noise Radiation,” was published as a conference paper and Stylianides presented on the research virtually for the AIAA AVIATION 2020 Conference in mid-June. Read the paper here.

Abstract: A computational acoustic analysis was completed on a commercial supersonic engine inlet with a spike center body. Thirty-five flow cases were considered with the auxiliary door opened at one frequency and circumferential mode. The analysis indicated that the directivity changes significantly with the varying velocities. The presence of leading edge separation at the lip of the auxiliary door proves to be a potential cause of these variances. The peak sound level and angle of the far field radiation at the first lobe are affected primarily by changes in the free stream velocity.