@article{chen_liu_edwards_fang_2026, title={Computational Study of Hybrid Propeller Configurations}, volume={1}, url={https://www.mdpi.com/2226-4310/13/1/94}, DOI={10.3390/aerospace13010094}, abstractNote={This study presents the first computational investigation of hybrid propeller configurations that combine toroidal and conventional blade geometries. Using Delayed Detached Eddy Simulation (DDES) with the Shear Stress Transport (SST) k−ω model for flow analysis and the Ffowcs Williams and Hawkings (FW–H) formulation for aeroacoustic prediction, five hybrid propeller designs were evaluated: a baseline model and four variants with modified loop-element spacing. The results show that the V-Gap-S configuration achieves the highest figure of merit (FM), producing over 10% improvement in propeller performance relative to the baseline, while also exhibiting the lowest turbulence kinetic energy (TKE) levels across multiple radial planes. Aeroacoustic analysis reveals quadrupole-like directivity for primary tonal noise, primarily driven by blade tip–vortex interactions, with primary tonal noise strongly correlated with thrust. Broadband noise and overall sound pressure level (OASPL) exhibited dipole-like patterns, influenced by propeller torque and FM, respectively. Comparisons of surface pressure, vorticity, and time derivatives of acoustic pressure further elucidate the mechanisms linking blade spacing to aerodynamic loading and noise generation. The results demonstrate that aerodynamic performance and aeroacoustics are strongly coupled and that meaningful noise reduction claims require performance conditions to be matched.}, journal={Aerospace}, author={Chen, Mingtai and Liu, Tianming and Edwards, Jack and Fang, Tiegang}, year={2026}, month={Jan} }
 @article{chen_liu_fang_2025, title={Experimental and Numerical Analysis of a Toroidal Propeller}, volume={38}, url={https://doi.org/10.1061/JAEEEZ.ASENG-6423}, DOI={10.1061/JAEEEZ.ASENG-6423}, abstractNote={This study presents an experimental and numerical analysis of a 254 mm toroidal propeller, focusing on its aerodynamic performance and acoustic characteristics. Experiments were conducted in an anechoic chamber, where a load cell and microphones captured propeller performance and aeroacoustic data. The propeller achieves a figure of merit of approximately 0.45, indicating moderate efficiency. Pressure differentials near the blade tips are identified as the primary contributors to thrust and torque, with the leading blade in a single loop reducing lift on the trailing blade by up to 50%. Vortex structures in the propeller’s slipstream, including root, tip, and central vortices, are analyzed, and curve-fitting techniques are used to model tip vortex trajectories at various rotational speeds. The Spalart–Allmaras model, coupled with the Ffowcs-Williams and Hawkings model in Reynolds-averaged Navier–Stokes equations, accurately predicts tonal noise but underestimates broadband noise and the overall sound pressure level (OASPL) due to its tendency to smooth out pressure fluctuations. A comparison with conventional advanced precision composite and wood propellers shows that the primary tonal noise, broadband noise, and OASPL increase with disk loading, underscoring the importance of consistent test conditions when comparing toroidal propellers with conventional designs. Overall, the study provides valuable insights into the performance characteristics of toroidal propellers and offers recommendations for future research.}, number={6}, journal={Journal of Aerospace Engineering}, author={Chen, Mingtai and Liu, Tianming and Fang, Tiegang}, year={2025}, month={Aug} }
 @article{chen_wimsatt_liu_fang_2025, title={Experimental and Numerical Study of a UAV Propeller Printed in Clear Resin}, volume={12}, url={https://doi.org/10.3390/aerospace12050362}, DOI={10.3390/aerospace12050362}, abstractNote={This paper presents an experimental and numerical investigation of a 254 mm resin-printed propeller operating at rotational speeds between 3000 and 9000 RPM. Propeller thrust and torque were measured using a six-degree-of-freedom load cell, while acoustic data were captured with a microphone positioned three times the propeller diameter from the center. To complement the experimental analysis, computational simulations were conducted using ANSYS Fluent with the detached eddy simulation (DES) model, the Ffowcs-Williams and Hawkings (FW-H) model, and a transient flow solver. The figure of merit (FM) results show that the resin propeller slightly outperforms two commercial counterparts with a marginal difference between the wood and resin propellers. Additionally, the resin propeller demonstrates better noise performance, exhibiting the lowest primary tonal noise, broadband noise, and overall sound pressure level (OASPL), with minimal differences between the two commercial counterparts. ANSYS Fluent simulations predict thrust and torque within a 10% error margin, showing particularly accurate results for primary tonal noise. A new trade-off index is proposed to assess the balance between propeller performance and aeroacoustics, revealing distinct trends compared to traditional metrics. Furthermore, aerodynamic phenomena such as flow separation on the leading edge near the tip, flow separation behind the middle trailing edge, and vortex interactions at the root are identified as key contributors to tonal and broadband noise. These findings provide valuable insights into propeller design and aeroacoustic optimization.}, number={5}, journal={Aerospace}, author={Chen, Mingtai and Wimsatt, Jacob and Liu, Tianming and Fang, Tiegang}, year={2025}, month={Apr} }