scholarly journals Determination of the aerodynamic characteristics of the tiltrotor with the wingtip-mounted coaxial rotors

2021 ◽  
pp. 108-116
Author(s):  
Sergii Povarov
Keyword(s):  
Vortex Method ◽  
Aerodynamic Characteristics ◽  
Graphical Form ◽  
Maximum Speed ◽  
Basic Model ◽  
Computational Aerodynamics ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Comparison Of The Results ◽  
Coaxial Rotors

The article describes the study of rotor-to-wing aerodynamic interaction for the wingtip-mounted coaxial rotors configuration of the tiltrotor aircraft. The influence of the rotor slipstreams on lift-to-drag ratio characteristic was determined. Obtained results were compared with similar characteristics of the equivalent in thrust conventional single rotor slipstreams impact. Using the computational aerodynamics methods (panel-vortex method) the flow around the tiltrotor model with the wingtip-mounted single and coaxial rotors has been simulated. A study of the basic model configuration with conventional single rotors, based on the technical characteristics of the AgustaWestland AW609 tiltrotor, was conducted. Further researches were conducted for a modified model where single rotors were replaced with equivalent in thrust coaxial rotors. The influence of the rotor slipstreams on the aerodynamic characteristics of the model for both directions of rotors rotation in coaxial combination is considered. Also, the dependence of the maximum lift-to-drag characteristic due to the coaxial rotor diameters change has been determined. The results show that the coaxial rotor slipstreams-to-wing aerodynamic interaction effect is the similar to the effect of conventional single rotor, but less intensive. Comparison of the results showed that a tiltrotor equipped with wingtip-mounted single rotors has approximately 20% greater maximum lift-to-drag characteristic than one equipped with coaxial rotors with the same thrust. However, the use of coaxial rotors allows getting higher maximum speed, when conventional single rotors lose the efficiency significantly. Therefore, it is advisable to conduct further research for the possibility of using coaxial rotors for tiltrotor aircrafts. The research results are presented in graphical form. The obtained data provides a basis for further studies of the described problem, and also will be useful for new tiltrotor design works.

scholarly journals Comparison of aerodynamic characteristics of convertible models with single and coaxial schemes of propellers

2020 ◽  
pp. 96-105
Author(s):  
Sergey Povarov
Keyword(s):  
Vortex Method ◽  
Aerodynamic Characteristics ◽  
Graphical Form ◽  
Maximum Speed ◽  
Basic Model ◽  
Computational Aerodynamics ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Comparison Of The Results ◽  
Coaxial Rotors

The article describes the study of rotor-to-wing aerodynamic interaction for the wingtip-mounted coaxial rotors configuration of the tiltrotor aircraft. The influence of the rotor slipstreams on lift-to-drag ratio characteristic was determined. Obtained results were compared with similar characteristics of the equivalent in thrust conventional single rotor slipstreams impact. Using the computational aerodynamics methods (panel-vortex method) the flow around the tiltrotor model with the wingtip-mounted single and coaxial rotors has been simulated. A study of the basic model configuration with conventional single rotors, based on the technical characteristics of the AgustaWestland AW609 tiltrotor, was conducted. Further researches were conducted for a modified model where single rotors were replaced with equivalent in thrust coaxial rotors. The influence of the rotor slipstreams on the aerodynamic characteristics of the model for both directions of rotors rotation in coaxial combination is considered. Also, the dependence of the maximum lift-to-drag characteristic due to the coaxial rotor diameters change has been determined. The results show that the coaxial rotor slipstreams-to-wing aerodynamic interaction effect is the similar to the effect of conventional single rotor, but less intensive. Comparison of the results showed that a tiltrotor equipped with wingtip-mounted single rotors has approximately 20% greater maximum lift-to-drag characteristic than one equipped with coaxial rotors with the same thrust. However, the use of coaxial rotors allows getting higher maximum speed, when conventional single rotors lose the efficiency significantly. Therefore, it is advisable to conduct further research for the possibility of using coaxial rotors for tiltrotor aircrafts. The research results are presented in graphical form. The obtained data provides a basis for further studies of the described problem, and also will be useful for new tiltrotor design works.

scholarly journals Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method

2018 ◽  
Vol 122 (1251) ◽  
pp. 693-714 ◽  
Author(s):  
J. Tan ◽  
Y. Sun ◽  
G. N. Barakos
Keyword(s):  
Flow Model ◽  
Particle Method ◽  
Reversed Flow ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Vortex Particle Method ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Coaxial Rotors ◽  
Vortex Particle

ABSTRACTRecent advances in coaxial rotor design have shown benefits of this configuration. Nevertheless, issues related to rotor-head drag, aerodynamic performance, wake interference, and vibration should also be considered. Simulating the unsteady aerodynamic loads for a coaxial rotor, including the aerodynamic interactions between rotors and rotor blades, is an essential part of analysing their vibration characteristics. In this article, an unsteady aerodynamic analysis based on a vortex particle method is presented. In this method, a reversed-flow model for the retreating side of the coaxial rotor is proposed based on an unsteady panel technique. To account for reversed flow, shedding a vortex from the leading edge is used rather than from the trailing edge. Moreover, vortex-blade aerodynamic interactions are accounted for. The model considers the unsteady pressure term induced on a blade by tip vortices of other blades, and thus accounts for the aerodynamic interaction between the rotors and its contribution to the unsteady airloads. Coupling the reversed-flow model and the vortex-blade aerodynamic interaction model with the viscous vortex-particle method is used to simulate the complex wake of the coaxial rotor. The unsteady aerodynamic loads on the X2 coaxial rotor are simulated in forward flight, and compared with the results of PRASADUM (Parallelized Rotorcraft Analysis for Simulation And Design, developed at the University of Maryland) and CFD/CSD computations with the OVERFLOW and the CREATE-AV Helios tools. The results of the present method agree with the results of the CFD/CSD method, and compare to it better than the PRASADUM solutions. Furthermore, the influence of the aerodynamic interaction between the coaxial rotors on the unsteady airloads, frequency, wake structure, induced flow, and force distributions are analysed. Additionally, the results are also compared against computations for a single-rotor case, simulated at similar conditions as the coaxial rotor. It is shown that the effect of tip vortex interaction plays a significant role in unsteady airloads of coaxial rotors at low speeds, while the rotor blade passing effect is obviously strengthened at high-speed.

scholarly journals Aerodynamic Modelling and Analysis of a Novel Mechanism for Chord and Camber Morphing Wing

2018 ◽  
Vol 188 ◽  
pp. 04002 ◽  
Author(s):  
Harun Levent Şahin ◽  
Bora Orçun Çakır ◽  
Yavuz Yaman
Keyword(s):  
Incompressible Flow ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
Maximum Speed ◽  
Structural Mechanism ◽  
Speed Range ◽  
Deployable Mechanism ◽  
Aerodynamic Modelling ◽  
Four Bar Linkage ◽  
Transport Theorem

This paper presents the aerodynamic modelling and analysis of surfaces created by a novel deployable mechanism, which is composed of a four-bar linkage and a scissor-structural mechanism (SSM) which contains several scissor-like elements (SLEs). With the help of that mechanism, which is located inside the trailing portion of wing section, continuous adjustment of the airfoil is possible. In order to highlight the advantageous aerodynamic characteristics of newly created airfoil geometries via proposed SSM, several aerodynamic analyses have been performed. The flow characteristics used for the analyses are determined by the flight envelope of an intended generic UAV. Since the maximum speed range of the sample aircraft is well below Mach 0.3, incompressible flow assumption is made throughout the solutions and conservation laws of Reynolds Transport Theorem are employed.

Modeling and Test of Aerodynamic Force for a Piezoelectric Transducer Drive Mechanism

2014 ◽  
Vol 631-632 ◽  
pp. 610-613
Author(s):  
Jing Lu ◽  
Yan Fang Hang ◽  
Ying Jun Hu
Keyword(s):  
Piezoelectric Transducer ◽  
Aerodynamic Force ◽  
Model Simulation ◽  
Aerodynamic Characteristics ◽  
System Model ◽  
Force Model ◽  
Initial Angle ◽  
Drive Mechanism ◽  
Force Mode ◽  
Comparison Of The Results

To reduce the complexity structure of a flapping rotor, a piezoelectric transducer drive mechanism is designed to achieve active flapping and passive rotary motion. Then, its aerodynamic force model is built by using Theodorsen's theory in order to analyze the aerodynamic characteristics of this system. Model simulation and experimental results show that flapping amplitude, flapping frequency and initial angle of attack make a significant role for aerodynamic characteristics. The effectiveness of aerodynamic force mode also can be seen from the comparison of the results.

scholarly journals Computational aerodynamics in architectural siting of the structures of agro-industrial complex

2021 ◽  
Vol 280 ◽  
pp. 03002
Author(s):  
Anton Makhinko ◽  
Nataliia Makhinko
Keyword(s):  
Aerodynamic Characteristics ◽  
Wind Effect ◽  
Cylinder Surface ◽  
Industrial Complex ◽  
Software Module ◽  
Element Mesh ◽  
Computational Aerodynamics ◽  
Sufficient Detail ◽  
Special Relations ◽  
Turbulent Airflow

The article presents study of wind effect on silo parks, which was carried out by computer simulation methods. A special modeling technique was created as a software module for the Ansys Workbench platform. A finite element mesh was developed in accordance with two requirements. Through the use of this mesh, which doesn’t contain needless elements which can be used for simplification of calculations and reduction of execution time, it is possible to describe the turbulent airflow in sufficient detail. The dimensions of all mesh elements are determined by special relations as the functions of the silo diameter and the Reynolds number. The major stage in this investigation was modeling of various options for flowing silos and their groups. As a result of the study, we have obtained aerodynamic characteristics of individual silos as part of silo parks and plotted charts of the distribution of pressure coefficients over the cylinder surface, changing the size of the silos, distances between them and local wind regime. Based on these data, we have drawn a conclusion about the optimal space planning locations of silos for different wind directions. Visualizations of turbulent flow around models at different speeds have also been obtained in this study.

scholarly journals ОСОБЛИВОСТІ ЗАБЕЗПЕЧЕННЯ АЕРОДИНАМІЧНИХ ХАРАКТЕРИСТИК РЕГІОНАЛЬНОГО ПАСАЖИРСЬКОГО ЛІТАКА

2019 ◽  
pp. 106-133
Author(s):  
Олександр Дмитрович Донець ◽  
Володимир Олександрович Кудрявцев
Keyword(s):  
High Speed ◽  
Research Work ◽  
Flight Dynamics ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Control Mode ◽  
Aviation Industry ◽  
Maximum Speed ◽  
Flight Tests ◽  
Aerodynamic Configuration

Principal results of the computational and research work performed during development of a regional passenger aircraft to ensure its aerodynamic characteristics are given. When creating the An-148-100/An-158 family of aircraft, such level of the aircraft aerodynamic perfection was achieved, which ensured fulfillment of the specified requirements for their flight performance – maximum speed, cruising flight altitude and flight range with different payloads. The developed aerodynamic configuration made it possible to create a family of regional passenger high-wing planes with a flight speed of up to 870 km/h (true speed) (M = 0.8), which have no analogues in the world aviation industry. Developed for the An-148-100 / An- 158 aircraft, supercritical profiles of the new generation with a large maximum relative thickness formed the basis of the aerodynamic configuration of a high-speed  wing with moderate sweep. The aircraft lift-to-drag ratio in cruise flight is Kcruise = 15.8, which corresponds to the worldwide values. Developed aerodynamic configuration of the wing high-lift devices provides high bearing properties of the wing during take-off and landing stages, which allows to fully meet the requirements for the runway required length of the base airfields Lrun = 1485...1950 m. Developed algorithms are implemented in the electric remote control system and provide necessary standard characteristics of stability, controllability and flight dynamics in the main control mode. Selected margins of the aircraft’s own static stability and effectiveness of its controls ensure safe completion of the flight in standby control mode. The certification flight tests of the An-148-100/An-158 airplanes confirmed full compliance of their take-off and landing performance, as well as the stability, controllability and flight dynamics characteristics with the requirements of the Certification basis in both standard and in failure situations tested in flight tests. Necessary and sufficient amount of experimental work was conducted in the lowspeed  and high-speed wind tunnels of the ANTONOV SC and TsAGI to verify the aerodynamic and spin characteristics of the An-148-100/An-158 airplane models, which improved the aerodynamic configuration of the aircraft and its individual units and allowed to apply the work results in calculation of aircraft strength, as well as for development of their systems.

scholarly journals Distance and Rotational Speed Analysis of Coaxial Rotors for UTHM C-Drone

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Che Muhammad Ikram Che Umar ◽  
◽  
Mohd Fadhli Zulkafli ◽  
Keyword(s):  
Rotational Speed ◽  
Rotation Speed ◽  
Flow Simulation ◽  
Power Efficient ◽  
Flow Simulations ◽  
System A ◽  
Coaxial Rotor ◽  
Cad Models ◽  
Total Thrust ◽  
Coaxial Rotors

The prototype of UTHM C-Drone use a coaxial hexacopter concept for its propulsion system. A coaxial rotor consists of two motor and two propellers mounted above each other and aligned in relation to their axis of rotation. The propellers are based on the T-Motor U15XXL KV29 model used in UTHM C-Drone. The distance between the two propellers is usually relative to the radius of the propeller or can be lesser. The objectives for this study are to investigate the effect of distance between upper and lower propeller in a coaxial rotors system and the effect of rotational speed. This study is important to ensure the C-Drone power efficient and capable to lift 180 kg payload. The CAD model of the propeller and coaxial rotors system were designed based on the specification from T-Motor company by Solidworks software and the flow simulations were conducted using Solidworks Flow Simulation module. The total of six CAD models; one for a single propeller and five for coaxial rotors with five difference of distance cases were constructed. For each model, the total thrust was tested from 50% throttle power up to the 90% throttle power. It was found that the coaxial rotors system can generate more thrust than a single propeller but less than double. It was also found that if the lower propeller rotates faster than the upper propeller, the increment of total thrust is very small. However, if the upper propeller rotates faster than the lower propeller, the total thrust increase significantly. For the case of faster upper propeller, as the higher the throttle applied, the thrust increment ratio will decrease, and the efficiency of the thrust produced will be affected. In addition, for same rotation speed, the thrust generated was lesser when both propellers rotate in a same direction compared to when each propeller rotates in the opposite directions of each other.

Aerodynamic Interactions Study on Low-Re Coaxial and Quad-Rotor Configurations

2017 ◽  
Author(s):  
Dhwanil Shukla ◽  
Nandeesh Hiremath ◽  
Sahaj Patel ◽  
Narayanan Komerath
Keyword(s):  
High Speed ◽  
Particle Image ◽  
Small Scale ◽  
Rotational Flow ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Image Velocimetry ◽  
Stereo Particle Image Velocimetry ◽  
Wake Model ◽  
Free Wake

Unmanned multi-rotor VTOL vehicles have recently gained importance in various applications such as videography, surveillance, search and rescue etc. suited to their small size and relatively cheap construction. Small scale UAVs struggle in providing satisfactory performance in terms of payload, range, and endurance because of higher viscosity-dominated losses, and due to yet to be understood rotor-rotor and rotor-airframe aerodynamic interactions. Viscosity dominated rotational flow field makes most potential flow methods, such as free wake model, invalid. A full N-S based approach for this problem is too expensive. Thus, a multi-rotor aerodynamic interaction study is necessary for understanding crucial phenomena, which will help in developing physics-based models which will be instrumental in multi-rotor UAV performance prediction and design optimization. In present work, a flow visualization and a high-speed stereo Particle Image Velocimetry (SPIV) study is done on two low Reynolds number multi-rotor arrangements with the aim of capturing vortex-vortex, blade-vortex and vortex-duct interactions. The first arrangement is a coaxial rotor in forward flight and another is an in-plane quad-rotor with and without duct. Instantaneous and average PIV data is being presented here with some observations and corresponding interpretations.

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