Lunch and Learn at China Garden Buffet: "Experimental Investigation of Upstream Geometry Effects on

When:  Apr 10, 2026 from 11:45 to 13:00 (ET)
Associated with  Dayton/Cincinnati Section
Abstract: Investigation of the impact of upstream nozzle geometry on screech generation mechanisms in twin supersonic jets. Through detailed acoustic and flow-field experiments, evidence is presented that demonstrates higher screech production and multimodal behavior along with broadband shock associated noise in nozzles featuring a plug-type design. Although the optimal nozzle design exhibits slightly higher broadband shock-associated noise in design operating condition, the plug nozzle’s pronounced screech tones dominate the overall sound pressure levels, exceeding by approximately 3–5 dB across nearly all tested conditions, including over expanded (2.5,2.7,3.0) and design nozzle pressure ratios NPR of 3.67. Additionally, a notable increase in high-frequency noise accompanies the screech tones in plug-type nozzles, suggesting the presence of smaller-scale turbulent structures upstream of the nozzle exit. This high-frequency acoustic signature is especially pronounced at lower observer angles, consistently appearing stronger in plug nozzles compared to their optimal counterparts across all measurement angles. Observations suggests the jet turbulence characteristics changes not just because of its design parameters rather the way the design is inculcated.
 
Biography: Arshad Mohammed is a Ph.D. candidate in Aerospace Engineering at the University of Cincinnati, specializing in experimental aeroacoustics and jet noise research. He earned his Bachelor’s degree in Mechanical Engineering from Jawaharlal Nehru Technological University (JNTU-K), India, before pursuing his Master’s degree at the University of Cincinnati. During his Master’s program, Arshad worked with Dr. Janet Dong on the design and development of an autonomous fire-extinguishing robot, a project that earned 1st place in the Thangs Design Challenge. This experience strengthened his interest in applied mechanical design and experimental systems. He later transitioned into PhD in aeroacoustics research, focusing on fully experimental investigations of supersonic jet noise. His doctoral work involves studying the effects of nozzle geometry—including single and twin nozzle configurations—and throat location on screech mechanisms and overall noise reduction. His research aims to better understand and mitigate high-intensity jet noise through geometry-driven design strategies. Arshad is expected to complete his Ph.D. by the end of this year and looks forward to contributing to aerospace research and acoustic design innovations.

Location

China Garden Buffet
112 Woodman Dr.
Dayton, OH 45431

Contact

Troy Hoeger
7574345873
tchoeger@earthlink.net