On the effect of popular additive manufacturing technologies on the performance and noise emission of UAV propellers J. García-Tíscar, P. Quintero, P. Varela, F.N. Ramírez, A. Cremades Aerospace Science and Technology, 2026 Noise remains a major concern for the widespread employment of Unmanned Air Vehicles (UAVs) operations, especially in urban environments. Moreover, not only must overall noise levels be considered when analyzing the acoustic impact of UAVs, but noise quality based on the spectral content of the acoustic signal must also be considered due to the psycho-acoustic effect on the listeners. Additionally, as UAVs become widespread, the ability to perform field replacement of propellers using additive manufacturing (AM) is of increased interest to many operators. However, as different AM techniques become popular, their impact on performance and noise must be assessed. In this investigation, the effect of manufacturing characteristics, such as surface roughness and flexibility, on the propeller thrust, torque, and acoustic signature is explored through an experimental campaign, revealing differences depending on the selected technique. A numerical experiment is then performed to isolate the effect of flexibility and roughness on these characteristics.
Aerodynamic and aeroacoustic interactions in multirotor aircraft for urban air mobility: A review Kangni Combey, Omer A. Elsayed, Andrea Magrini, Federico N. Ramirez, Sen Wang, Khaoula Qaissi, Hajar Chouiyakh, Lourenço T. L. Pereira, Daniele Ragni Physics of Fluids, 2026 The rapid growth of urbanization and increasing road traffic congestion are straining ground transportation infrastructure for both conventional and emergency purposes, driving the need for alternative mobility solutions. urban air mobility (UAM) offers a promising pathway by deploying electric vertical takeoff and landing (eVTOL) aircraft to enable efficient and flexible aerial transport in dense urban environments. However, the successful integration of UAM into city airspace faces critical technical challenges, both at the vehicle and operational levels. In particular, complex aerodynamic and aeroacoustic interactions between closely spaced propellers significantly influence vehicle performance, energy efficiency, and public acceptance. This work presents a review of experimental and computational studies on propeller–propeller and propeller–wing interactions, highlighting the state-of-the-art methodologies and their application to multirotor eVTOL designs. Results indicate that distributed electric propulsion systems arranged in side-by-side configurations exhibit minimal thrust degradation, typically less than 3% compared to an isolated propeller. However, reductions in propeller spacing can induce unsteady blade loading and increase tonal noise levels by up to 10 dB. In contrast, one-after-another configurations may suffer thrust losses of up to 80%, due to slipstream ingestion by the rear propeller, with a lateral separation of at least twice the propeller radius required to recover performance within 4% of the isolated case. The review also addresses propeller–wing interactions that modify local pressure distributions and spanwise lift, particularly in wing-mounted distributed propulsion configurations. The insights provided establish a foundation for developing efficient, low-noise multirotor architectures for future UAM integration.
Realizing topological edge states in graphenelike elastic metamaterials Zhen Huang, Penglin Gao, Federico N. Ramírez, Jorge García-Tíscar, Alberto Broatch, Jiu Hui Wu, Fuyin Ma, José Sánchez-Dehesa Physical Review Applied, 2024 The study of topological states in electronic structures, which allows robust transport properties against impurities and defects, has been recently extended to the realm of elasticity. This work shows that nontrivial topological flexural edge states located on the free boundary of the elastic graphene-like metamaterial can be realized without breaking the time reversal, mirror, or inversion symmetry of the system. Numerical calculations and experimental studies demonstrate the robust transport of flexural waves along the boundaries of the designed structure. The topological edge states on the free boundary are not limited by the size of the finite structure, which can reduce the scale of the topological state system. In addition, unlike the edge states localized on the free boundary in graphene where the group velocity is zero, the edge states on the elastic metamaterial plate have propagation states with non-zero group velocity. There is a frequency range for the edge states, and we introduce the concept of Shannon entropy for elastic waves and use it to assess the frequency range of the edge states in graphene-like elastic metamaterials. This work represents a relevant advance in the study of elastic wave topological states, providing a theoretical basis for engineering applications such as vibration reduction and vibration isolation of mechanical structures.
Evaluation of different FW-H surfaces and modal decomposition techniques for the acoustic analysis of UAV propellers through detached eddy simulations A. Broatch, R. Navarro, J. García-Tíscar, F.N. Ramírez Aerospace Science and Technology, 2024 Noise has been a much-studied problem since the beginning of aviation because it is one of the main factors affecting its social acceptance. In recent years, the expansion of Unmanned Aerial Vehicles (UAVs) has led to increased research on propellers working at low Reynolds numbers, which are typically found in this type of aircraft. This paper begins with an Improved Delayed Detached Eddy Simulation (IDDES) of a commercial nine-inch UAV propeller. The Ffowcs-Williams and Hawkings (FW-H) approach is then used to compute the acoustic propagation from the simulation results. Both aerodynamic performance and acoustic signature results in hover flight are validated experimentally. Then, the influence of different FW-H permeable surfaces is methodologically evaluated, finding that magnified SPL values at low frequencies are obtained when using cylinders due to vortical structures passing through the bottom cap, and that the use of spheres appears to be the most consistent approach. Once a validated, time-resolved flow field has been obtained, different data-driven modal decomposition techniques, such as Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), are applied to the 3D pressure field. This enables a better understanding of the propeller acoustic modes and the assessment of the suitability of each technique for this problem, especially when Reduced Order Models (ROMs) are sought.
EFFECT OF POPULAR ADDITIVE MANUFACTURING TECHNOLOGIES ON THE PERFORMANCE AND ACOUSTICS OF UAV PROPELLERS Icas Proceedings, 2024
PERFORMANCE AND ACOUSTIC ANALYSIS OF A DISTRIBUTED ELECTRIC PROPULSION UNMANNED AIRCRAFT Icas Proceedings, 2024
NUMERICAL AND EXPERIMENTAL EVALUATION OF NOISE AND PERFORMANCE IN UAV PROPELLERS José R. Serrano, Jorge García-Tíscar, Pedro Quintero, Federico N. Ramírez Proceedings of the ASME Turbo Expo, 2023 Due to the increasing use of unmanned air vehicles (UAVs) for civil and military purposes, accurate evaluation of this kind of aircraft is becoming a fundamental aim during their development. Particularly, propellers are often the most critical elements influencing a UAV’s performance and noise emission. Therefore, selecting the appropriate tools for modeling the behavior of this element becomes crucial, especially at the design stages, evaluating both their accuracy and cost. In this paper, we will test the suitability of different tools for numerical modeling and perform an experimental campaign to validate the numerical results. Particularly, from the computational point of view, the performance of a typical propeller will be evaluated for various values of the advance ratio and various rotational speeds at hover, paying special attention to the thrust and thrust coefficient. Various modeling approaches will be analyzed in this sense, including low-order Blade Element Momentum Theory (BEMT) evaluation, Reynolds Averaged Navier-Stokes (RANS) methodologies (both stationary using a moving reference frame and transient), and transient Detached Eddy Simulations (DES), to analyze the turbulent structures arising in these devices. Noise emission will be evaluated at the most significant working conditions by applying a Ffowcs-William & Hawkings approach to the computed unsteady results and a simplified Farassat formulation to the BEMT results. These numerical calculations will be carried out using open-source software such as OpenFOAM and libAcoustics in the case of CFD modeling or in-house codes for low-order models. Regarding experimental validation measurements, the hovering propeller’s thrust and far-field acoustic measurements will be performed in an anechoic chamber. The experimental setup will also be mounted in a wind tunnel for forward flight tests and to validate the performance results at different advance ratios. Furthermore, rapid prototyping is a necessary part of the development process for small propellers; thanks to progress in additive manufacturing (AM), this could even become the preferred way to manufacture in-house spares. In this paper, we will also assess the suitability of Fused Deposition Modeling — one of the most popular AM techniques — for manufacturing research propeller prototypes by comparing the propulsive and acoustic performance of a commercial propeller against its 3D-printed version.
A study of the mesh effect on a rocket plume simulation Federico N. Ramírez, Mara S. Escarti-Guillem, Luis M. García-Raffi, Sergio Hoyas Results in Engineering, 2022 The use of reliable CFD models for the simulation of spacecraft launch is crucial due to the complexity of obtaining experimental data. The validity of the results depends on the numerical schemes used and the mesh. In this paper two CFD simulations of a supersonic jet have been conducted using OpenFOAM. Two different mesh types have been compared, hexaedral and polyhedral. Our calculations show that the former is more accurate and faster than the latter. Moreover, the minimum required element has been estimated to be 50 cells/diameter.
RECENT SCHOLAR PUBLICATIONS
Aerodynamic and aeroacoustic interactions in multirotor aircraft for urban air mobility: A review K Combey, OA Elsayed, A Magrini, FN Ramirez, S Wang, K Qaissi, ... Physics of Fluids 38 (1) , 2026 2026 Citations: 11
On the effect of popular additive manufacturing technologies on the performance and noise emission of UAV propellers J García-Tíscar, P Quintero, P Varela, FN Ramírez, A Cremades Aerospace Science and Technology, 111466 , 2025 2025
Realizing topological edge states in graphenelike elastic metamaterials Z Huang, P Gao, FN Ramírez, J García-Tíscar, A Broatch, JH Wu, F Ma, ... Physical Review Applied 21 (5), 054015 , 2024 2024 Citations: 4
Evaluation of different FW-H surfaces and modal decomposition techniques for the acoustic analysis of UAV propellers through detached eddy simulations A Broatch, R Navarro, J García-Tíscar, FN Ramírez Aerospace Science and Technology 146, 108956 , 2024 2024 Citations: 21
Effect of popular additive manufacturing technologies on the performance and acoustics of UAV propellers J García-Tíscar, P Quintero, FN Ramírez, A Cremades ICAS Proceedings- 34th Congress of the International Council of the … , 2024 2024 Citations: 3
Performance and acoustic analysis of a distributed electric propulsion unmanned aircraft R Navarro, LM García-Cuevas, J García-Tíscar, FN Ramírez ICAS Proceedings- 34th Congress of the International Council of the … , 2024 2024 Citations: 2
Evaluation of different CFD models for aeroacoustics assessment of low Reynolds number propellers FN Ramírez Universitat Politècnica de València , 2023 2023
Numerical and Experimental Evaluation of Noise and Performance in UAV Propellers JR Serrano, J García-Tíscar, P Quintero, FN Ramírez Turbo Expo: Power for Land, Sea, and Air 86939, V001T01A023 , 2023 2023 Citations: 7
Design of unmanned air vehicles with distributed electric propulsion: range improvement and noise emission LM García-Cuevas, J García-Tíscar, P Varela, FN Ramírez Aerospace Europe Conference - EUCASS - CEAS - 2023 , 2023 2023 Citations: 4
A study of the mesh effect on a rocket plume simulation FN Ramírez, MS Escarti-Guillem, LM García-Raffi, S Hoyas Results in Engineering 13, 100366 , 2022 2022 Citations: 11
Estudio CFD de la influencia del deflector sobre el campo aero-acústico en el despegue del cohete VEGA FN Ramírez 2021
Levantamiento industrial y modelización 3D de un helicóptero militar BO-105 FN Ramírez Universitat Politècnica de València , 2019 2019
MOST CITED SCHOLAR PUBLICATIONS
Evaluation of different FW-H surfaces and modal decomposition techniques for the acoustic analysis of UAV propellers through detached eddy simulations A Broatch, R Navarro, J García-Tíscar, FN Ramírez Aerospace Science and Technology 146, 108956 , 2024 2024 Citations: 21
Aerodynamic and aeroacoustic interactions in multirotor aircraft for urban air mobility: A review K Combey, OA Elsayed, A Magrini, FN Ramirez, S Wang, K Qaissi, ... Physics of Fluids 38 (1) , 2026 2026 Citations: 11
A study of the mesh effect on a rocket plume simulation FN Ramírez, MS Escarti-Guillem, LM García-Raffi, S Hoyas Results in Engineering 13, 100366 , 2022 2022 Citations: 11
Numerical and Experimental Evaluation of Noise and Performance in UAV Propellers JR Serrano, J García-Tíscar, P Quintero, FN Ramírez Turbo Expo: Power for Land, Sea, and Air 86939, V001T01A023 , 2023 2023 Citations: 7
Realizing topological edge states in graphenelike elastic metamaterials Z Huang, P Gao, FN Ramírez, J García-Tíscar, A Broatch, JH Wu, F Ma, ... Physical Review Applied 21 (5), 054015 , 2024 2024 Citations: 4
Design of unmanned air vehicles with distributed electric propulsion: range improvement and noise emission LM García-Cuevas, J García-Tíscar, P Varela, FN Ramírez Aerospace Europe Conference - EUCASS - CEAS - 2023 , 2023 2023 Citations: 4
Effect of popular additive manufacturing technologies on the performance and acoustics of UAV propellers J García-Tíscar, P Quintero, FN Ramírez, A Cremades ICAS Proceedings- 34th Congress of the International Council of the … , 2024 2024 Citations: 3
Performance and acoustic analysis of a distributed electric propulsion unmanned aircraft R Navarro, LM García-Cuevas, J García-Tíscar, FN Ramírez ICAS Proceedings- 34th Congress of the International Council of the … , 2024 2024 Citations: 2
On the effect of popular additive manufacturing technologies on the performance and noise emission of UAV propellers J García-Tíscar, P Quintero, P Varela, FN Ramírez, A Cremades Aerospace Science and Technology, 111466 , 2025 2025
Evaluation of different CFD models for aeroacoustics assessment of low Reynolds number propellers FN Ramírez Universitat Politècnica de València , 2023 2023
Estudio CFD de la influencia del deflector sobre el campo aero-acústico en el despegue del cohete VEGA FN Ramírez 2021
Levantamiento industrial y modelización 3D de un helicóptero militar BO-105 FN Ramírez Universitat Politècnica de València , 2019 2019
