Session: 10-06-01: Fluid Mechanics, Machine Learning and Predictive Simulations in Fluid Flows, Aerospace Systems, Thermodynamics, Heat Transfer, Energy Systems, Fluid Power and Pneumatic systems, and Renewable Energy Applications I

Paper Number: 165534

Aerodynamic Analysis of a Composite Material Drone With a 3-Axis Rotating Mechanism Propeller 

Our research project intended to advance composite-material drones' design and performance optimization through a multi-faceted analysis integrating computational fluid dynamics (CFD), rigid-body dynamics, and structural evaluations. Focusing on a quadcopter equipped with a novel 3-axis rotating mechanism—previously conceptualized for dynamic thrust vectoring—the design has been validated with its aerodynamic feasibility and operational efficiency. The mechanism enables independent propeller rotation around three axes, enhancing maneuverability by dynamically adjusting thrust vectors during flight. Using ANSYS Fluent, steady-state CFD simulations were conducted with the Moving Reference (MRF) method to model an eight-inch composite propeller (carbon fiber-reinforced polymer matrix) under varying angles of attack (AoA: 0°–15°) and rotational speeds (RPM: 5000–15,000). The MRF approach simplified the rotating domain’s interaction with the stationary fluid domain, balancing computational efficiency with accuracy for preliminary design validation.

Aerodynamic performance metrics were analyzed to identify optimal operating conditions, including lift (CL) and drag (CD) coefficients. At 5° AoA, the propeller achieved CL = 4.7 and CD = 0.3, striking an optimal balance between thrust generation and energy efficiency. This configuration minimized flow separation and vortex shedding, which are critical for maintaining stability in multi-axis rotations. RPM-dependent simulations revealed a nonlinear relationship between thrust and rotational speed: while thrust increased with RPM, drag forces grew disproportionately beyond 12,000 RPM due to turbulent skin friction and tip-vortex interactions, corroborating prior studies on propeller energy losses.

Our research findings include a 400 mm center-to-center propeller spacing to eliminate aerodynamic interference and ensure that wake turbulence from one rotor does not disrupt adjacent propellers. This distance aligns with tip-vortex decay rates and minimizes blade-wake interaction (BWI) noise, a critical factor in multi-rotor systems. Comparative analysis of single-propeller and dual-propeller configurations confirmed that spacing below 400 mm degrades thrust by 18–22% due to wake ingestion. Larger separated distances preserve aerodynamic independence without compromising structural compactness.

The CFD results were cross-validated against experimental data, showing a strong correlation in thrust trends but minor discrepancies in absolute values at high RPMs, attributable to turbulence model limitations (k-omega SST) and steady-state assumptions. Despite this, the simulations accurately predicted stall behavior at AoAs greater than 10°, aligning with theoretical aerodynamics. Structural evaluations of the composite airframe highlighted its role in damping vibrational harmonics induced by rotor dynamics, further enhancing flight stability.

Our research provides actionable insights for designing multi-axis thrust-vectoring drones, emphasizing the interplay between composite material properties, aerodynamic efficiency, and geometric configuration. The validated 3-axis mechanism demonstrates the potential for applications in agile UAVs operating in constrained or turbulent environments. Future work will integrate transient simulations and experimental prototyping to refine dynamic performance under real-world conditions.

Presenting Author: Jagrut Desai SAN JOSE STATE UNIVERSITY

Presenting Author Biography: Motivated Mechanical Engineer specializing in Design & Manufacturing, holding an M.S. in Mechanical Engineering from San José State University with a focus on aerodynamics. With over two years of industry experience, he leverages expertise in SolidWorks, ANSYS, and AutoCAD to develop innovative solutions for complex engineering challenges. His work emphasizes collaborative problem-solving, technical precision, and advancing product functionality, driven by a passion for innovation and sustainable engineering practices.

Authors:

Jagrut Desai SAN JOSE STATE UNIVERSITY
Raymond Yee SAN JOSE STATE UNIVERSITY
Varun Mathur Intuitive Surgical