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Journal articles on the topic 'Aerodynamic load'
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1
Tomasz Lusiak, Andrej Novak, Martin Bugaj, and Radovan Madlenak. "Assessment of Impact of Aerodynamic Loads on the Stability and Control of the Gyrocopter Model." Communications - Scientific letters of the University of Zilina 22, no. 4 (October 1, 2020): 63–69. http://dx.doi.org/10.26552/com.c.2020.4.63-69.
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Aerodynamic modelling currently relates to development of mathematical models to describe the aerodynamic forces and moments acting on the aircraft. It is a challenging part of aerodynamics that defines a comprehensive approach to using traditional methods and modern techniques to obtain relevant data. The most complicated task for the aerodynamics and flight dynamics is definition, computation and quantification of the aerodynamic description of an object. This paper presents how to determine the aerodynamic load on a gyrocopter and defines the effect on its stability and control. The first step to solution is to develop simpler approximate aerodynamic model - a model that can be used in analysis of aerodynamic load and can represent the aerodynamic properties of the gyrocopter with an acceptable degree of accuracy. Control and stability are very important parts of aircraft characteristics and therefore those characteristics were analyzed in simulation. Finally, the aerodynamic data outputs are assessed in terms of impact of aerodynamic loads on stability and control of the gyrocopter model.
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Perez-Becker, Sebastian, Francesco Papi, Joseph Saverin, David Marten, Alessandro Bianchini, and Christian Oliver Paschereit. "Is the Blade Element Momentum theory overestimating wind turbine loads? – An aeroelastic comparison between OpenFAST's AeroDyn and QBlade's Lifting-Line Free Vortex Wake method." Wind Energy Science 5, no. 2 (June 15, 2020): 721–43. http://dx.doi.org/10.5194/wes-5-721-2020.
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Abstract. Load calculations play a key role in determining the design loads of different wind turbine components. To obtain the aerodynamic loads for these calculations, the industry relies heavily on the Blade Element Momentum (BEM) theory. BEM methods use several engineering correction models to capture the aerodynamic phenomena present in Design Load Cases (DLCs) with turbulent wind. Because of this, BEM methods can overestimate aerodynamic loads under challenging conditions when compared to higher-order aerodynamic methods – such as the Lifting-Line Free Vortex Wake (LLFVW) method – leading to unnecessarily high design loads and component costs. In this paper, we give a quantitative answer to the question of load overestimation of a particular BEM implementation by comparing the results of aeroelastic load calculations done with the BEM-based OpenFAST code and the QBlade code, which uses a particular implementation of the LLFVW method. We compare extreme and fatigue load predictions from both codes using sixty-six 10 min load simulations of the Danish Technical University (DTU) 10 MW Reference Wind Turbine according to the IEC 61400-1 power production DLC group. Results from both codes show differences in fatigue and extreme load estimations for the considered sensors of the turbine. LLFVW simulations predict 9 % lower lifetime damage equivalent loads (DELs) for the out-of-plane blade root and the tower base fore–aft bending moments compared to BEM simulations. The results also show that lifetime DELs for the yaw-bearing tilt and yaw moments are 3 % and 4 % lower when calculated with the LLFVW code. An ultimate state analysis shows that extreme loads of the blade root out-of-plane bending moment predicted by the LLFVW simulations are 3 % lower than the moments predicted by BEM simulations. For the maximum tower base fore–aft bending moment, the LLFVW simulations predict an increase of 2 %. Further analysis reveals that there are two main contributors to these load differences. The first is the different way both codes treat the effect of the nonuniform wind field on the local blade aerodynamics. The second is the higher average aerodynamic torque in the LLFVW simulations. It influences the transition between operating modes of the controller and changes the aeroelastic behavior of the turbine, thus affecting the loads.
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Tian, Xiao, Wenhui Yan, and Kun Zhang. "Numerical Calculation of 1P Aerodynamic Loads on Aviation Propellers." Journal of Physics: Conference Series 2747, no. 1 (May 1, 2024): 012043. http://dx.doi.org/10.1088/1742-6596/2747/1/012043.
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Abstract To accurately predict the 1P aerodynamic loads of aviation propellers, this paper established a mathematical model of aviation propeller 1P aerodynamic loads based on the coupling method of blade element theory and momentum theory. Correction methods such as the Prandtl tip correction method and the propeller root correction method were implemented to further improve calculation accuracy. A 1P aerodynamic load calculation procedure was developed based on the mathematical model by using the Matlab software. 1P aerodynamic loads of a three-blade propeller were predicted for three different angles including 3 °, 9 °, and 12°. The numerical calculation results show that the calculated aerodynamic characteristic parameters of individual propeller blades obtained based on the propeller 1P aerodynamic load mathematical model deviate less than 6% from the CFD simulation results, and regular periodic pulsations are observed. The numerical calculations in this paper show that the propeller 1P aerodynamic load calculation procedure developed based on this model can accurately predict the propeller 1P aerodynamic load, which can provide some reference for the study of aviation propeller aerodynamic characteristics.
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Cicolani, L. S., J. G. A. da Silva, E. P. N. Duque, and M. B. Tischler. "Unsteady aerodynamic model of a cargo container for slung-load simulation." Aeronautical Journal 108, no. 1085 (July 2004): 357–68. http://dx.doi.org/10.1017/s0001924000005170.
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Abstract The problem of simulation models capable of predicting the aerodynamic instability of helicopter slung-load cargo containers and bluff bodies is addressed. Instability for these loads is known to depend on unsteady frequency-dependent aerodynamics, but simulation models that include the unsteady aerodynamics do not currently exist. This paper presents a method for generating such models using computational fluid dynamics (CFD) to generate forced-oscillation aerodynamic data and frequency domain system identification techniques to generate a frequency response from the CFD data and to identify a transfer function fit to the frequency response. The method is independent of the responsible flow phenomenon and is expected to apply to bluff-bodies generally. Preliminary results are presented for the case of the 6- by 6- by 8-ft CONEX (container express) cargo container. The present work is based on two-dimensional (2D) aerodynamic data for the CONEX side force and yaw moment generated by a forced oscillation in which frequency is varied smoothly over the range of interest. A first-order rational polynomial transfer function is found adequate to fit the aerodynamics, and this is shown to provide a good match with flight test data for the yawing motion of the CONEX.
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Gennaretti, M., and C. Ponzi. "Finite-state aerodynamic modelling for gust load alleviation of wing–tail configurations." Aeronautical Journal 103, no. 1021 (March 1999): 147–58. http://dx.doi.org/10.1017/s0001924000064964.
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Abstract A finite-state aerodynamics methodology is proposed for the analysis of the forces generated by a gust. To illustrate and assess the methodology, gust-response and gust-alleviation applications are included. Finite-state aerodynamics denotes a technique to approximate aerodynamic loads so as to yield an aircraft model of the type ẋ = Ax + Bu (state-space formulation). In this paper, a finite-state formulation is proposed to include the presence of a gust. The aerodynamic loads to be approximated are evaluated here by using a frequency-domain boundary-element formulation; the flow is assumed to be irrotational except for a zero-thickness vortex layer (wake). The gust-alleviation application consists of determining a control law for reducing the response to a vertical gust disturbance, as measured by the centre of mass acceleration. Two optimal-control approaches are considered for the synthesis of the control law: one uses the classical linear-quadratic regulator (LQR), whereas the second includes the additional feed-forward of the gust velocity ahead of the aircraft. Deflections of ailerons and elevators are assumed to be the control variables. Numerical results deal with responses to both a deterministic ‘1 – cosine’ gust distribution and a stochastic von Kármán spectrum. They indicate that the finite-state aerodynamic model proposed is capable of approximating, with a high level of accuracy, both the aerodynamic loads induced by the aircraft kinematics variables and those induced by the control variables, over a wide frequency range.
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Ma, Kaichao, Changhong Tang, Jianye Zhang, Xiaofei Niu, and Qingzhi Fan. "Flight Load Design of Nacelle of Carrier-Based Propeller Transport Aircraft." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 6 (December 2020): 1249–56. http://dx.doi.org/10.1051/jnwpu/20203861249.
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The carrier-based propeller transport aircraft has a compact layout, where the large nacelle in size and weight is sensitive to propeller slipstream, and thus calls for sophisticated flight load design studies, which are still insufficient considering domestic experience. In detail, the design methods on aerodynamic load, inertial load, gyrostatic moment, as well as studies on design criteria and maneuver simulation technology are shown for a reference aircraft. The design range applied to this nacelle's flight load is firstly determined by understanding and selecting the design criteria. The typical loadcases of the nacelle are derived from aircraft maneuver simulation. The data of pressure distribution under a series of propeller slipstream strengths is obtained by CFD method. The Design Loads and Design Loadcases of the nacelle are calculated and selected. The effects of the propeller slipstream are compared in an example of the increment on aerodynamic load in a maneuver. The results show that the Design Loads of the nacelle are obtained from the abrupt pitching maneuver under the maximum normal load factor (Nz), the yawing maneuver under the Design Dive Speed(VD), and the maximum propeller pull under the maximum landing weight; the transverse loads of the nacelle are dominated by the aerodynamic load, and the normal loads are dominated by the inertial load, in which the inertial force exceeds the aerodynamic force by 4 times under the extreme circumstances. In some manoeuvres or status, the total aerodynamic force of the whole nacelle is increased by above 90% due to propeller slipstream; the front part of the nacelle which is close to the propeller sees a much bigger increment.
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Liu, Mengjuan, Han Wu, Junqi Xu, Xiaohui Zeng, Bo Yin, and Zhanzhou Hao. "Research on sliding mode controller of the high-speed maglev train under aerodynamic load." Advances in Mechanical Engineering 14, no. 10 (October 2022): 168781322211278. http://dx.doi.org/10.1177/16878132221127857.
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The high-speed maglev train will be subjected to extremely obvious aerodynamic load and instantaneous aerodynamic impact during passing another train, which brings significant challenges to the train’s suspension stability and safe operation. It’s necessary to consider the influence of aerodynamic load and shock waves in the design of suspension control algorithms. Traditional proportion integration differentiation (PID) control cannot follow the change of vehicle parameters or external disturbance, which is easy to cause suspension fluctuation and instability. To improve the suspension stability and vibration suppression of the high-speed maglev train under aerodynamic load and impact, we design a siding mode controller introducing the primary suspension’s deformation to replace the aerodynamic load on the electromagnet. Furthermore, we establish the train’s dynamic simulation model with three vehicles and compare the designed controller and the PID controller for their performance in controlling the model suspension stability in the presence of the train operating in open air. Simulation results show that the sliding mode control (SMC) method proposed in this paper can effectively restrain the electromagnet fluctuation of the train under aerodynamic loads.
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Didenko, Anton, Vladislav Borisenko, and Jose Leoro. "Load distribution method in helicopter blade multibody dynamics system." E3S Web of Conferences 258 (2021): 09076. http://dx.doi.org/10.1051/e3sconf/202125809076.
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The paper focuses on the loads applied to the helicopter blade cross-sections in the multibody dynamics system. The main objective is to simplify the blade aerodynamics calculation and avoid time-consuming CFD methods. For this reason, the way of computing blade aerodynamics is proposed by using multibody dynamics methods with a linear-elastic blade model. As the primary tool for further research, the MCS Adams software package is selected. Splitting the main rotor blade into a finite number of sections, each having its own average value of installation and coning angles, simplifies the calculation. Afterward, expressions for the total flow velocity around the blade section and its angle of attack are obtained through vector operations. This provides a measure of aerodynamic forces acting on each section in its cross-sectional coordinate system. In conclusion, the article provides the formalized method of aerodynamic force distribution between blade sections in the multibody model as well as the correlation between the flow coordinate system and the blade chord coordinate system.
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Xie, Yonghui, Kun Lu, Le Liu, and Gongnan Xie. "Fluid-Thermal-Structural Coupled Analysis of a Radial Inflow Micro Gas Turbine Using Computational Fluid Dynamics and Computational Solid Mechanics." Mathematical Problems in Engineering 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/640560.
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A three-dimensional fluid-thermal-structural coupled analysis for a radial inflow micro gas turbine is conducted. First, a fluid-thermal coupled analysis of the flow and temperature fields of the nozzle passage and the blade passage is performed by using computational fluid dynamics (CFD). The flow and heat transfer characteristics of different sections are analyzed in detail. The thermal load and the aerodynamic load are then obtained from the temperature field and the pressure distribution. The stress distributions of the blade are finally studied by using computational solid mechanics (CSM) considering three cases of loads: thermal load, aerodynamics load combined with centrifugal load, and all the three types of loads. The detailed parameters of the flow, temperature, and the stress are obtained and analyzed. The numerical results obtained provide a useful knowledge base for further exploration of radial gas turbine design.
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Harinaldi Harinaldi and Farhan T Pratama. "Transient Analysis on the Crosswind Effect to the Aerodynamics of High-speed Train Travelled on the Bridge Between Two Tunnels at Jakarta -Bandung Track." CFD Letters 16, no. 10 (June 2, 2024): 64–80. http://dx.doi.org/10.37934/cfdl.16.10.6480.
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The rapid evolution of global transportation technology is exemplified by Indonesia's innovative high-speed train initiative, linking Jakarta and Bandung in an impressive 45 minutes. Operating at 350 km/h, the HST CR400AF underscores the importance of aerodynamics in high-speed rail systems. This study delves into the significant impact of crosswind on key aerodynamic factors (drag, lift, rolling moment) within the tunnel-bridge-tunnel configuration. Leveraging Computational Fluid Dynamics (CFD) through ANSYS FLUENT, the analysis explores crosswind variations at 0 m/s, 10 m/s, and 25 m/s. Results reveal a proportional increase in aerodynamic load with higher crosswind intensities: 1.67 times for drag, 58.8 times for lift, and 29.8 times for rolling moment. Notable observations include pronounced aerodynamic load fluctuations during the "OUT" process, with the head section bearing the greatest load, followed by the tail and middle sections. These findings contribute valuable insights to the global discourse on enhancing safety and efficiency in high-speed rail systems
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Heathcote, D. J., I. Gursul, and D. J. Cleaver. "Aerodynamic Load Alleviation Using Minitabs." Journal of Aircraft 55, no. 5 (September 2018): 2068–77. http://dx.doi.org/10.2514/1.c034574.
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Enciu, K., and A. Rosen. "Aerodynamic modelling of fin stabilised underslung loads." Aeronautical Journal 119, no. 1219 (September 2015): 1073–103. http://dx.doi.org/10.1017/s0001924000011143.
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AbstractBox-like slung loads exhibit periodic yaw response instabilities, while carried externally by a helicopter. When coupled with the slung load longitudinal and lateral pendulum motions, these instabilities result in significant pendulum oscillations of the load. High amplitude oscillations lead in many cases to the limiting of a load’s flight envelope. Using wind tunnel and flight tests, rear mounted fins were previously demonstrated as efficient means for stabilisation of a problematic load. However, the lack of a proper analytical model of the stabilised load’s aerodynamic characteristics, led to a trial and error development process, without an appropriate physical understanding of the stabilisation problem. The present paper describes a method for the aerodynamic modeling of fins stabilised slung loads based on a limited number of simple static wind-tunnel tests. The resulting database is incorporated in a dynamical slung load simulation that shows good agreement with dynamic wind-tunnel tests. The applicability of the proposed method is demonstrated, by the calculation of stabilised loads aerodynamic databases for interim fin inclination angles not covered by tests.
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Amrutheswara Krishnamurthy and Dr.Suresh Nagesh. "Aerodynamic Effect on Stability and Lift Characteristics of an Elevated Sedan Car." ARAI Journal of Mobility Technology 2, no. 2 (May 13, 2022): 205–13. http://dx.doi.org/10.37285/ajmt.1.2.6.
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There is a strong interaction between air and vehicle components. Aerodynamics plays a significant role in a vehicle's fuel efficiency. The contact patch load between the tire and road is directly related to the vehicle load. In this research, the lift forces generated due to the additional wing attached to the car model with different spans and heights of the wing location from the car body is considered for study. The loads due to change in Angle of Attack (AOA) and their effect on the tire loads are studied. The upward vertical force produced from aerodynamic loads reduces the wheel load of the car virtually. A tire's coefficient of friction would decrease with upward vertical force. This balance load implies that a lightweight car would make more efficient use of its tires than a heavier car. ANSYS Fluent is used for the Computational Fluid Dynamics (CFD) study. The validation of airflow characteristics, lift and drag forces from simulations are done with wind tunnel testing data. Varying the angle of attack, wingspan, height between the car and the wing's lower surface, one can increase the capacity of the payload by 10% or fuel efficiency by 10% to 20%.
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Petrone, Nicola, Matteo Capuzzo, Erik De Paoli, and Nicola Biliato. "The Measurement of Aerodynamic Loads using Dynamometric Load Cells." ATZautotechnology 4, no. 3 (May 2004): 56–59. http://dx.doi.org/10.1007/bf03246829.
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Zhang, Xuyao, Congxin Yang, and Shoutu Li. "Influence of the Heights of Low-Level Jets on Power and Aerodynamic Loads of a Horizontal Axis Wind Turbine Rotor." Atmosphere 10, no. 3 (March 11, 2019): 132. http://dx.doi.org/10.3390/atmos10030132.
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The influence of the heights of low-level jets (LLJs) on the rotor power and aerodynamic loads of a horizontal axis wind turbine were investigated using the fatigue, aerodynamics, structures, and turbulence code. The LLJ and shear inflow wind fields were generated using an existing wind speed spectral model. We found that the rotor power predicted by the average wind speed of the hub height is higher than the actual power in relatively weak and shallow LLJ inflow conditions, especially when the LLJ height is located inside the rotor-swept area. In terms of aerodynamic loads, when the LLJ height is located inside the rotor-swept area, the root mean square (RMS) rotor thrust coefficient and torque coefficient increase, while the RMS rotor unbalanced aerodynamic load coefficients, including lateral force, longitudinal force, tilt moment, and yaw moment, decreased. This means that the presence of both positive and negative wind shear in the rotor-swept area not only increases the rotor power but also reduces the unbalanced aerodynamic loads, which is beneficial to the operation of wind turbine. Power spectrum analysis shows no obvious difference in the power spectrum characteristics of the rotor torque and thrust in LLJ inflow conditions with different heights.
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Martín-San-Román, Raquel, Jon Cerrada-Garcés, Guillén Campaña-Alonso, Beatriz Méndez-López, José Azcona-Armendáriz, and Alvaro Cuerva-Tejero. "Assessment of the azimuthal loads variation by a bi-rotor configuration." Journal of Physics: Conference Series 2767, no. 2 (June 1, 2024): 022015. http://dx.doi.org/10.1088/1742-6596/2767/2/022015.
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Abstract Multi wind turbine configurations are emerging in the offshore wind energy market. The modelling of the aerodynamics of these systems is challenging, due to the small lateral distance between rotors and the subsequent interaction between wakes. Previous analysis in the literature showed that, due to this interaction, multi wind turbine concepts present the advantage of an increment in power production, if the rotors are laterally aligned. However, the counterpart in the variation of the blade loads throughout the revolution, has yet to be analysed in depth. This study focuses on the differences observed in azimuthal cycles of blade aerodynamic loads in side-by-side bi-rotor configurations, as an initial analysis of their potential impact on fatigue loads. The analysis has been developed using two aerodynamic codes, with different levels of fidelity. These models are: a Free Vortex filament Method (FVM) combined with an unsteady Lifting Line (LL) model, and a URANS-blade resolved approach. The simulations show that the sectional blade loads are affected by the adjacent rotor, changing the shape of the aerodynamic load cycles along the azimuth. The load azimuthal distributions predicted by a FVM and a URANS models have been compared, showing agreement on the shape of the cycle with slight differences on maximum peak values, specially at the inner sections of the blade. The FVM model has predicted increments in the blade load cycles, with respect to a single rotor case, with a maximum amplitude of a 3% for out-of-plane forces, and a 8% for in-plane forces. The difference in the azimuthal position of both rotors (phase shift angle) mainly affects the azimuthal shape and not so much the characteristic amplitude of these cycles. Finally, including geometric angles as tilt or pre-cone, produces imbalances between the blade sectional forces of the different rotors.
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Schulz, Christian W., Umut Özinan, Stefan Netzband, Po Wen Cheng, and Moustafa Abdel-Maksoud. "The Impact of Unsteadiness on the Aerodynamic Loads of a Floating Offshore Wind Turbine." Journal of Physics: Conference Series 2626, no. 1 (October 1, 2023): 012064. http://dx.doi.org/10.1088/1742-6596/2626/1/012064.
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Abstract The role of unsteadiness in the aerodynamics of Floating Offshore Wind Turbines (FOWT) remains a subject of discussion among the research community. Therefore, it must be investigated whether and to what extent transient aerodynamic phenomena impact the loads of a wind turbine rotor undergoing motions in unsteady winds. The study of transient aerodynamic phenomena is closely linked to the question of whether the modern Blade Element Momentum Theory (BEMT) methods can be considered reliable for the simulation of FOWTs. In this work, investigations are carried out to identify the relevant transient aerodynamic phenomena and quantify their effects on the torque and thrust of the Floatgen wind turbine. A free-wake panel method is utilised to identify and quantify transient parts of the load response to a set of simplified unsteady scenarios: a wind gust, a harmonic surge motion and a rotor speed oscillation. Transient contributions to the load behaviour of the wind turbine can be identified in all scenarios under consideration. In addition, the ability of a state-of-the-art BEMT method to model the identified transient contributions is evaluated. While an agreement of the qualitative impact of the transient aerodynamic phenomena at moderate motion frequencies is found, a contradicting behaviour of the simulation models becomes apparent at high motion frequencies. This indicates the presence of a transient, three-dimensional wake effect that cannot be reproduced by the common unsteady corrections for BEMT methods.
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Esmaeili, Ali, Hossein Jabbari, Hadis Zehtabzadeh, and Majid Zamiri. "Investigating Mechanical Response and Structural Integrity of Tubercle Leading Edge under Static Loads." Modelling 5, no. 2 (May 25, 2024): 569–84. http://dx.doi.org/10.3390/modelling5020030.
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This investigation into the aerodynamic efficiency and structural integrity of tubercle leading edges, inspired by the agile maneuverability of humpback whales, employs a multifaceted experimental and computational approach. By utilizing static load extensometer testing complemented by computational simulations, this study quantitatively assesses the impacts of unique wing geometries on aerodynamic forces and structural behavior. The experimental setup, involving a Wheatstone full-bridge circuit, measures the strain responses of tubercle-configured leading edges under static loads. These measured strains are converted into stress values through Hooke’s law, revealing a consistent linear relationship between the applied loads and induced strains, thereby validating the structural robustness. The experimental results indicate a linear strain increase with load application, demonstrating strain values ranging from 65 με under a load of 584 g to 249 με under a load of 2122 g. These findings confirm the structural integrity of the designs across varying load conditions. Discrepancies noted between the experimental data and simulation outputs, however, underscore the effects of 3D printing imperfections on the structural analysis. Despite these manufacturing challenges, the results endorse the tubercle leading edges’ capacity to enhance aerodynamic performance and structural resilience. This study enriches the understanding of bio-inspired aerodynamic designs and supports their potential in practical fluid mechanics applications, suggesting directions for future research on manufacturing optimizations.
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Srivastava, Nilabh, Peter T. Tkacik, and Russell G. Keanini. "Ascending rockets as macroscopic self-propelled Brownian oscillators." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, no. 2148 (September 12, 2012): 3965–94. http://dx.doi.org/10.1098/rspa.2012.0273.
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High-fidelity numerical experiments and theoretical modelling are used to study the dynamics of a sounding-rocket-scale rocket, subject to altitude-dependent random wind and nozzle side loads and deterministic aerodynamic loading. This paper completes a series of studies that showed that Ornstein–Uhlenbeck (OU) rotational dynamics arise when random nozzle side loads dominate wind and aerodynamic loading. In contrast to the earlier work, this paper elucidates that under conditions where aerodynamic, wind and nozzle side loads are comparable, the rocket behaves as stochastic Brownian oscillator. The Brownian oscillator model allows straightforward interpretation of the complex rotational dynamics observed: three dynamical regimes—each characterized by differing balances between nozzle-side-load-induced torques, spring-like aerodynamic torques and mass flux damping torques—characterize rocket ascent. Further, the paper illuminates that in the limit where wind and aerodynamic loads are small, random mass flux variations exponentially amplify side-load-induced rotational stochasticity. In this practical limit, pitch/yaw dynamics are described by a randomly damped OU process; an exact solution of the associated Fokker–Planck equation can be obtained and used to compute, e.g. time-dependent pitch/yaw rate means and variances.
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Čavoj, Ondřej, Ondřej Blaťák, Petr Hejtmánek, and Jan Vančura. "Vehicle Ride Height Change Due To Radial Expansion Of Tires." Journal of Middle European Construction and Design of Cars 13, no. 2 (November 1, 2015): 22–27. http://dx.doi.org/10.1515/mecdc-2015-0008.
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Abstract In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height - axle load equations, the ride height change due to tire radial expansion was determined.
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Berci, Marco. "On Aerodynamic Models for Flutter Analysis: A Systematic Overview and Comparative Assessment." Applied Mechanics 2, no. 3 (July 29, 2021): 516–41. http://dx.doi.org/10.3390/applmech2030029.
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This work reviews different analytical formulations for the time-dependent aerodynamic load of a thin aerofoil and clarifies numerical flutter results available in the literature for the typical section of a flexible wing; inviscid, two-dimensional, incompressible, potential flow is considered in all test cases. The latter are investigated using the exact theory for small airflow perturbations, which involves both circulatory and non-circulatory effects of different nature, complemented by the p-k flutter analysis. Starting from unsteady aerodynamics and ending with steady aerodynamics, quasi-unsteady and quasi-steady aerodynamic models are systematically derived by successive simplifications within a unified approach. The influence of the aerodynamic approximations on the aeroelastic stability boundary is then rigorously assessed from both physical and mathematical perspectives. All aerodynamic models are critically discussed and compared in the light of the numerical results as well, within a comprehensive theoretical framework in practice. In all cases, results accuracy depends on the aero-structural arrangement of the flexible wing; however, simplified unsteady and simplified quasi-unsteady aerodynamic approximations are suggested for robust flutter analysis whenever the wing’s elastic axis lies ahead of the aerofoil’s control point.
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Weimin, Sun. "Distributing Three-Dimensional Aerodynamic Load to Fem Nodes." MATEC Web of Conferences 293 (2019): 04006. http://dx.doi.org/10.1051/matecconf/201929304006.
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Aiming at the requirement of the load conversion in aeronautics and astronautics static strength analysis, a three-dimensional aerodynamic load equivalent distribution method based on least squares is proposed. Based on the principle of the closest distance, the corresponding relationship between the aerodynamic node and the finite element node is established to ensure that each finite element node has its corresponding aerodynamic node. Under the requirement of minimizing the variance of load obtained by each node allocation, the least squares algorithm is used to obtain the results of the load conversion. Through an engineering example of aerodynamic distribution, it is verified that the method presented in this paper not only has high accuracy but also can ensure the uniformity of load distribution before and after load distribution.
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Duan, Qing Song, Cun Ming Ma, and Bin Xie. "Research on Aerodynamic Impacts of Snow on Bridge Decks." Advanced Materials Research 774-776 (September 2013): 68–72. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.68.
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With the development of economy and technology, many long span bridges have been constructed. However, oversize thickness and long duration of snow on these long span bridges might lead to security issues. The computational fluid dynamics software FLUENT is employed to simulate the snow effect on the bridges. According to the two-phase fluid theory, the relationship between air phase and snow phase is one-way coupling. The corresponding changes of snow load on the bridge deck under the action of strong winds are studied in this paper and the comparative analysis about aerodynamic impacts before and after the snow are conducted as well. According to the results, the snow has notable influence on the aerodynamic characteristics of bridge decks. Keywords: computational fluid dynamics; two-phase fluid theory; snow load; aerodynamics;
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Islam, Hafizul, Serge Sutulo, and C. Guedes Soares. "Aerodynamic Load Prediction on a Patrol Vessel Using Computational Fluid Dynamics." Journal of Marine Science and Engineering 10, no. 7 (July 7, 2022): 935. http://dx.doi.org/10.3390/jmse10070935.
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Aerodynamic loads and moments on a naval patrol vessel are investigated using computational fluid dynamic simulations based on the OpenFOAM solver. After the initial turbulence, time, and grid dependency study, model scale simulations were performed for a wide range of inflow angles to predict aerodynamic forces and moments acting on the vessel at different heading conditions. For validation, model scale results were compared with wind tunnel data for similar hull forms. Finally, full-scale simulations were performed for a few cases to investigate possible scale effects on simulation results. The revealed scale effect turned out significant only for the yaw moment response. In this study, we aimed to produce reliable aerodynamic load data for the high-speed vessel, which is essential to developing reliable manoeuvring models. We conclude that Computational Fluid Dynamics is capable of providing reliable aerodynamic load predictions for high-speed vessels with sophisticated superstructures, in an economical manner.
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Lu, Yaohui, Dewen Zhang, Heyan Zheng, Chuan Lu, Tianli Chen, Jing Zeng, and Pingbo Wu. "Analysis of the aerodynamic pressure effect on the fatigue strength of the carbody of high-speed trains passing by each other in a tunnel." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 8 (November 2, 2018): 783–801. http://dx.doi.org/10.1177/0954409718809469.
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When two high-speed trains pass through a tunnel, the aerodynamic changes are more complex and drastic than in open air owing to the interference of the tunnel wall and the entry effect. The impact on the carbody fatigue strength is very significant in the fatigue reliability design of the carbody. In this paper, the sequential coupling method was used for the first time to study the effect of pressure waves on the fatigue strength in a large-scale and complex carbody structure. The computational fluid dynamics method was used to calculate and analyze the aerodynamic pressure wave of the intersection of the trains in a long and short tunnel. A full-scale finite element shell model of the carbody structure was established. Then, the time integration method was used to convert the transient pressure wave into the aerodynamic loads bearing by the side wall of the carbody. The inhomogeneous stress concentrations at the restraint points were eliminated by the inertial release method; moreover, a finite element analysis of the carbody was carried out under the combined aerodynamic and mechanical loads. The Goodman fatigue strength curve of the aluminum alloy carbody was drawn. The influence of the aerodynamic load on the fatigue strength of the vehicle body was analyzed and compared under the entry effect of the short tunnel. The results show that the aerodynamic load of the short tunnel has a significant impact on the fatigue strength of the carbody owing to the train's entry effect. The safety factor of the fatigue strength is 15% less than that of the long tunnel aerodynamic load. In this paper, computational fluid dynamics and finite element method were used to analyze and evaluate the impact of the pressure wave on the fatigue strength of the carbody, which is of great reference value in the structural design of the carbody subjected to complex aerodynamic loads.
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Niven, A. J., and S. W. Tait. "A new approach to the third order calibration of internal strain gauge balances used for aerodynamic load measurement." Aeronautical Journal 104, no. 1041 (November 2000): 501–8. http://dx.doi.org/10.1017/s0001924000017875.
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Abstract With respect to wind tunnel aerodynamic load measurement, an internal strain gauge balance (often referred to as a sting balance) is essentially a compact load cell designed to fit within a cavity of the aerodynamic body and form a link between the model and a fixed ground point via a sting support system. The structure of an internal strain gauge balance is designed to incorporate a series of planar surfaces such that the deflection of each surface is predominantly induced by a unique aerodynamic load. Strain gauges, mounted on groups of surfaces in a Wheatstone bridge arrangement produce output signals proportional to the applied aerodynamic loads. A strain gauge balance is calibrated by applying known loads, measuring the bridge outputs and then formulating an equation which relates the two variables together. Although calibration techniques are well established, reservations have been recently expressed concerning the ability of the associated calibration equation to satisfactorily model the response of the balance when subjected to a six component aerodynamic loading. This generally accepted calibration equation (referred to here as the traditional equation) results in a quadratic approximation to the behaviour of the output signals with applied loads, whereas a more appropriate variation would be cubic. Other limitations of the traditional calibration equation are that the behaviour of the balance to two simultaneously applied loads is based upon limited combinations of the two applied loads, and that the acquisition of the required loads from the strain gauge signals is frequently based upon an approximate matrix inversion method. The proposed calibration equation, described within this paper, models the behaviour of the sting balance to the third order, takes account of all possible combinations of two simultaneously applied loads, and avoids the use of an approximate matrix inversion when deriving the desired aerodynamic loading from the signal outputs. It is also shown that the proposed method may be used to determine the interaction of all possible combinations of up to three simultaneously applied loads.
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Chiariello, Antonio, Salvatore Orlando, Pasquale Vitale, Mauro Linari, Raffaele Longobardi, and Luigi Di Palma. "Development of a Morphing Landing Gear Composite Door for High Speed Compound Rotorcraft." Aerospace 7, no. 7 (June 30, 2020): 88. http://dx.doi.org/10.3390/aerospace7070088.
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In the framework of fast rotorcraft, smoothness and flushness of external aerodynamic surfaces present challenges for high-speed conditions, where aerodynamics is the driver of helicopter performance. For AIRBUS-RACER helicopter the main landing gear trap doors are parts of the lower wing skins (in retracted configuration) affecting helicopter performance by minimizing the drag. Flushness requirements must not be in contrast with the functionally of the Landing gear system that must open and close the doors during the landing gear retraction-extension phases at moderately low velocity. To manage these goals, a novel design logic has been identified to support the trap doors development phase. The identified way to proceed needs of relevant numerical method and tool as well. This method is aimed at identifying the main landing gear composite compartment doors in pre-shaped configuration to match the smoothness and door-stopper engagements over each aerodynamic conditions. The authors propose a detailed non-linear Finite Element method, based on MSC Nastran (MSC Software, Newport Beach, US) SOL-400 solver in which the structure is modelled with deformable contact bodies in a multiple load step sequence, open door condition and pre-shaped, deformed under actuator pre-load, under flight load conditions. The method includes the entire pre-stressed field due to the preload and the actual door stiffness, considering the achieved large displacement to verify the most representative strain field during loads application. The paper defines a robust methodology to predict the deformation and ensure the most appropriate door “pre-bow” and pre-load, in order to achieve the desiderated structural shape that matches aerodynamic requirements. The main result is the identification of a pre-shaped doors configuration for the Airbus RACER Fast Rotorcraft.
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Zhang, Mingming, Shurong Hao, and Anping Hou. "Study on the Intelligent Modeling of the Blade Aerodynamic Force in Compressors Based on Machine Learning." Mathematics 9, no. 5 (February 25, 2021): 476. http://dx.doi.org/10.3390/math9050476.
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In order to obtain the aerodynamic loads of the vibrating blades efficiently, the eXterme Gradient Boosting (XGBoost) algorithm in machine learning was adopted to establish a three-dimensional unsteady aerodynamic force reduction model. First, the database for the unsteady aerodynamic response during the blade vibration was acquired through the numerical simulation of flow field. Then the obtained data set was trained by the XGBoost algorithm to set up the intelligent model of unsteady aerodynamic force for the three-dimensional blade. Afterwards, the aerodynamic load could be gained at any spatial location during blade vibration. To evaluate and verify the reliability of the intelligent model for the blade aerodynamic load, the prediction results of the machine learning model were compared with the results of Computation Fluid Dynamics (CFD). The determination coefficient R2 and the Root Mean Square Error (RMSE) were introduced as the model evaluation indicators. The results show that the prediction results based on the machine learning model are in good agreement with the CFD results, and the calculation efficiency is significantly improved. The results also indicate that the aerodynamic intelligent model based on the machine learning method is worthy of further study in evaluating the blade vibration stability.
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Zheng, Xinqian, Chuang Ding, and Yangjun Zhang. "Influence of different loads on the stresses of multistage axial compressor rotors." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 5 (April 19, 2016): 787–98. http://dx.doi.org/10.1177/0954410016642461.
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Multistage axial compressors are widely used in the gas turbine engines. The strength of rotors is one of the key factors for the reliability of multistage axial compressors. The stresses of rotors at real working conditions can be caused by the centrifugal load, thermal load, and aerodynamic load. It is important to figure out the roles and the mechanism of the three kinds of loads in the stresses generating process. In this paper, the stresses of rotors in a typical five-stage axial compressor are calculated with different kinds of loads by solid–fluid coupling method. The results show that the proportion of the stress caused by centrifugal load is more than 80% of the total stress, which is dominant. The maximum proportion of the stress caused by thermal load is about 20% of the total stress at the front stages. However, the influence of thermal load is quite different from the first stage to the last stage. It is surprising that thermal load can decrease the stresses of the last stage rotor, which is mainly because of the variation of radial temperature gradient at disks for different stages. The proportion of the stress caused by aerodynamic load is usually less than 4%, and it tends to make the stresses at the suction side of the blades lower and enlarge it at the pressure side. According to the above results, centrifugal load is necessary of consideration at the conceptual design phase for the multistage axial compressor rotors. At preliminary three-dimensional design phase, centrifugal load and thermal load should be considered together. At optimized three-dimensional design phase, aerodynamic load cannot be neglected and all the three loads should be considered.
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Silva, Adriana Correia da, and Michael Muskulus. "VAWT support structure mass sensitivity due to aerodynamic load scaling." Journal of Physics: Conference Series 2626, no. 1 (October 1, 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2626/1/012003.
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Abstract The X-rotor wind turbine is an X-shaped hybrid vertical axis wind turbine whose power take-off is done by horizontal axis rotors located at the tip of the lower blades. Based on an initial basic study, the present study developed a preliminary jacket design as the turbine support structure. Steady aerodynamic loads were obtained from an actuator cylinder model and dynamic load simulations including wave loads were performed. The structure was checked according to fatigue damage and maximum yielding for representative site-specific load cases for fatigue and ultimate limit states. Even though the use of a conventional jacket was shown to be feasible for the new turbine concept, the overall mass of the support structure obtained by the higher fidelity model was higher than the initial prediction. The design was driven by the fatigue damage, caused by large cyclical loads on every rotor rotation. The effect of a hypothetical aerodynamic load reduction on the jacket mass was investigated. The developed design methodology was also applied to the design of equivalent jackets after a load reduction of 75% and 50% and the mass of the structure was shown to be sensible, with a respective reduction of 25% and 48%. This result demonstrates that different design strategies that influence the magnitude of the aerodynamic loads (e.g. the control strategy) could lead to a more cost-efficient jacket design.
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Liu, J., J. L. Ge, H. Yang, W. S. Chen, J. H. Wu, and Q. L. Qu. "Analysis of Aircraft Parking Stability Based on Atmosphere Boundary Theory." Journal of Physics: Conference Series 2458, no. 1 (March 1, 2023): 012026. http://dx.doi.org/10.1088/1742-6596/2458/1/012026.
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Abstract Based on numerical simulation technology, the aerodynamic load research of civil aircraft parked on the ground is conducted. The CRM model parked on the ground is established by CFD software. Based on the atmospheric boundary layer theory, the seven incoming flow conditions for numerical calculation are designed. And the aerodynamic loads’ change of the aircraft model is calculated when the -90° sideslip angle. The result shows that the mooring load on the nose landing gear mainly comes from the longitudinal load caused by the upwards pitching moment on the flat tail and the lateral load caused by the yaw moment; since the rolling moment coefficient is less than the pitching moment coefficient by two orders of magnitude, which hardly affects the mooring load. The study provides a reference for reducing the mooring load of civil aircraft under heavy wind conditions.
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Daemei, Abdollah B., Amiraslan Darvish, Roya Aeinehvand, and Amirali Razzaghipour. "Large-Eddy Simulation (LES) on the Square and Triangular Tall Buildings to Measure Drag Force." Advances in Civil Engineering 2021 (May 25, 2021): 1–11. http://dx.doi.org/10.1155/2021/6666895.
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The wind load issues play a significant role in designing tall buildings, which has sometimes been considered an even more essential factor than earthquake loads. Also, investigating wind behavior in tall buildings is a crucial issue in architectural and structural design. A primary concern of wind engineering and aerodynamics is drag force. Drag force refers to a solid object’s behavior in the relative wind flow velocity direction in terms of fluid dynamics. The investigation involved only drag forces. The Autodesk Flow Design 2014 software was utilized as a wind tunnel simulator. The Large Eddy Simulation (LES) method was used for turbulence solving. This study aims to optimize tall square and triangular-shaped buildings in order to reduce drag force under along-wind motion. For this purpose, architectural aerodynamic strategies such as chamfered, rounded, and recessed corners were applied as aerodynamic modifications. Moreover, aerodynamic forms, including tapering and setting back on shapes, were applied on 24 building models. Generally, the height (H) and breadth (b) ratios were set to H: 200 m, which is equivalent to almost 60 stories, and b: 25 m wide. The obtained results indicate that model S5 (with a square floor plan) achieved 0.65 CD, and the t1 (with a triangular floor plan) achieved 0.30 CD, which could provide the best building model to reduce drag force. In this regard, the s1 could perform over 50% better in reducing wind load. Concerning the aerodynamic modification performance, the simulation results indicate that these modifications were able to lead to over 50% better performance in reducing wind force in square samples compared to triangular samples.
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Zhang, Zhe, Qiang Wang, Shida Song, Chengchun Zhang, Luquan Ren, and Yingchao Zhang. "Joint Research on Aerodynamic Characteristics and Handling Stability of Racing Car under Different Body Attitudes." Energies 15, no. 1 (January 5, 2022): 393. http://dx.doi.org/10.3390/en15010393.
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With the rapid development of FSAE, the speed of racing cars has increased year by year. As the main research content of racing cars, aerodynamics has received extensive attention from foreign teams. For racing cars, the aerodynamic force on the aerodynamic device ultimately acts on the tires through the transmission of the body and the suspension. When the wheel is subjected to the vertical load generated by the aerodynamic device, the ultimate adhesion capacity of the wheel is improved. Under changing conditions, racing wheels can withstand greater lateral and tangential forces. Therefore, the effects of aerodynamics have a more significant impact on handling stability. The FSAE racing car of Jilin University was taken as the research object, and this paper combines the wind tunnel test, the numerical simulation and the dynamics simulation of the racing system. The closed-loop design process of the aerodynamics of the FSAE racing car was established, and the joint study of aerodynamic characteristics and handling stability of racing car under different body attitudes was realized. Meanwhile, the FSAE car was made the modification of aerodynamic parameter on the basis of handling stability. The results show that, after the modification of the aerodynamic parameters, the critical speed of the car when cornering is increased, the maneuverability of the car is improved, the horoscope test time is reduced by 0.525 s, the downforce of the car is increased by 11.39%, the drag is reduced by 2.85% and the lift-to-drag ratio is increased by 14.70%. Moreover, the pitching moment is reduced by 82.34%, and the aerodynamic characteristics and aerodynamic efficiency of the racing car are obviously improved. On the basis of not changing the shape of the body and the aerodynamic kit, the car is put forward to shorten the running time of the car and improve the comprehensive performance of the car, so as to improve the performance of the car in the race.
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Lee, Jaein, Jinyoung Shin, Donghyun Cho, Hyeongsuk Jung, Taekyu Choi, Jonghoon Lee, Youngho Kim, and Sitae Kim. "Analyses on Aerodynamic and Inertial Loads of an Airborne Pod of High Performance Fighter Jet." Journal of the Korea Institute of Military Science and Technology 25, no. 1 (February 5, 2022): 9–22. http://dx.doi.org/10.9766/kimst.2022.25.1.009.
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A fighter performing a reconnaissance mission is equipped with a pod that drives optical/infrared sensors for acquiring and identifying target information on the lower part of the fuselage. Due to the nature of the reconnaissance mission, the fighter performs high speed evasive maneuvers, and the resulting load should be considered importantly for the development of the pod. This paper concerns a numerical investigation into the inertial and aerodynamic loads of the airborne pod of high performance aircrafts. For the aerodynamic load analysis, the pylon and pod shapes are added to the fighter 3D model, and the commercial software was used for static and dynamic analysis. Considering the practical mission conditions, the common/extreme conditions were established respectively in the static and dynamic situations of pods and the driving torque could be tripled under dynamic conditions. In the analysis of inertia load, a 3-DOF model considering roll and turning maneuvers was derived by the Lagrangian method, and then the numerical integration method was applied to the analysis. As a results, it was conformed that the inertia load was generally induced at a low level compared to the aerodynamic load, but depending on the unbalance mass condition of the pod, the inertia load cannot be negligible.
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Oh, Gyeongtaek, Jongho Park, Jeongha Park, Hongju Lee, Youdan Kim, Sang-Joon Shin, Jaemyung Ahn, and Sangbum Cho. "Load relief control of launch vehicle using aerodynamic angle estimation." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 8 (March 23, 2017): 1598–605. http://dx.doi.org/10.1177/0954410017699435.
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A nonlinear closed-loop load relief scheme is proposed to reduce the aerodynamic load during the ascent phase of a launch vehicle. The proposed controller is designed based on a back-stepping and sliding-mode control scheme with aerodynamic angle feedback. A hybrid load-relief strategy using the load relief scheme around the period of the maximum dynamic pressure and the traditional minimum-drift scheme during the other period is proposed. An aerodynamic angle estimator is also developed using a Kalman filter for the feedback of the load relief control. Numerical simulation is conducted to demonstrate the performance of the proposed strategy as well as the potential benefits.
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Yu, Jing Mei, Yan Hong Yu, and Pan Pan Liu. "Horizontal Axis Wind Turbine Numerical Simulation of Two Dimensional Angle of Attack." Advanced Materials Research 619 (December 2012): 111–14. http://dx.doi.org/10.4028/www.scientific.net/amr.619.111.
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wind power is the most effective form of wind energy utilization, modern large-scale wind turbine with horizontal axis wind mainly. Horizontal axis wind turbine aerodynamic performance calculation of the wind turbine aerodynamics research hot spot, is a wind turbine aerodynamic optimization design and calculation of critical load. Horizontal axis wind turbine airfoil aerodynamic performance of the wind turbine operation characteristics and life plays a decisive role". Using Fluent software on the horizontal axis wind turbine numerical simulation, analysis of the United States of America S809NREL airfoil aerodynamic characteristics of different angles of attack numerical simulation, analyzes the different angles of attack in the vicinity of the pressure, velocity distribution. By solving the two-dimensional unsteady, compressible N-S equations for the calculation of wind turbine airfoil S809used the characteristics of flow around. N-S equation in body-fitted coordinate system is given, with the Poisson equation method to generate the C grid.
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Da, Kang, Wang Yongliang, Zhong Jingjun, and Liu Zihao. "Pre-Deformation Method for Manufactured Compressor Blade Based on Load Incremental Approach." International Journal of Turbo & Jet-Engines 37, no. 3 (August 27, 2020): 259–65. http://dx.doi.org/10.1515/tjj-2017-0024.
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AbstractThe blade deformation caused by aerodynamic and centrifugal loads during operating makes blade configurations different from their stationary shape. Based on the load incremental approach, a novel pre-deformation method for cold blade shape is provided in order to compensate blade deformation under running. Effect of nonlinear blade stiffness is considered by updating stiffness matrix in response to the variation of blade configuration when calculating deformations. The pre-deformation procedure is iterated till a converged cold blade shape is obtained. The proposed pre-deformation method is applied to a transonic compressor rotor. Effect of load conditions on blade pre-deformation is also analyzed. The results show that the pre-deformation method is easy to implement with fast convergence speed. Neither the aerodynamic load nor centrifugal load can be neglected in blade pre-deformation.
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Li, Yun Feng. "Loads Calculation of Pitch Bearing of Wind Turbine." Advanced Materials Research 148-149 (October 2010): 479–84. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.479.
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Loads calculation process for pitch bearing of wind turbine was presented. The aerodynamic of the rotor was analyzed by using momentum theory and blade element theory firstly; then the aerodynamic loads, the gravitational loads and the centrifugal loads of the pitch bearing were calculated along each axis of the bearing coordinate system; thirdly, all the loads of each direction of the pitch bearing load were composed into three loads, they are radial, axial and tilting moment loads. A calculation example was given at last.
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Zhu, Gui Hua, Tuan Hui Qiu, and Min Xie. "The Analysis of Aerodynamic Load for High Speed Centrifugal Compressor Blade." Advanced Materials Research 675 (March 2013): 103–6. http://dx.doi.org/10.4028/www.scientific.net/amr.675.103.
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With the ANSYS Workbench software,the 3D fluid model of the impeller for the centrifugal compressor is set up,whose design flow is 3.2kg/s,rotating speed is 32473r/min,pressure ratio is 3.8,and then with the method of CFD,the k-ε two equations model is selected as the turbulence model,in the condition of design speed,the fluid region of the impeller is simulated under eight different flow rate,the aerodynamic load of the impeller blade and its distribution is acquired under different flow rate,the results showed that the location of the largest aerodynamic load is in the blade that near the outlet of impeller,under the design flow rate condition,the largest aerodynamic load is 0.1969MPa,the aerodynamic load increases with the flow rate decreases.
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Yang, Wenjun, Huiqun Yuan, and Tianyu Zhao. "Multi-field coupling dynamic characteristics based on Kriging interpolation method." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 6 (May 16, 2016): 1088–99. http://dx.doi.org/10.1177/0954410016648350.
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Multi-field coupling problems are taken more and more attention mainly because of the higher requirement of load, efficiency, and reliability in aero-engine operation. This research takes an aero-engine compressor as the research object, 3D flow field and structural models are established. For the method of cyclic symmetric, single-sector model is selected as the calculation domain. Considering the influence of former stator wakes, compressor flow field is simulated. The article analyzes the distribution law of unsteady aerodynamic load on rotor blade. Based on Kriging model, load transfer of aerodynamic pressure and temperature is achieved from flow field to blade structure. Then the effects of centrifugal force, aerodynamic pressure and temperature load are discussed on compressor vibration characteristic and structural strength. The results show dominant fluctuation frequencies of aerodynamic load on rotor blade are manly at frequency doubling of stator–rotor interaction, especially at one time frequency (1 × f0). Magnitude and pulsation amplitude on pressure surface are far greater than that on suction surface. Load transfer with Kriging model has a higher precision, it can meet the requirement of multi-field coupling dynamic calculation. In multi-field coupling interaction, temperature load makes the natural vibration frequencies decrease obviously, centrifugal force is the main source of deformation and stress. Bending stress induced by aerodynamic pressure and temperature load can counteract part of bending stress induced by centrifugal force. However, temperature load causes the maximum displacement of blade-disk system to increase.
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Salman, Abbass. "Flutter Phenomena Effected by The Aerodynamic Load." Engineering and Technology Journal 24, no. 3 (March 25, 2005): 210–26. http://dx.doi.org/10.30684/etj.24.3a.2.
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Dadonov, Mikhail, Alexander Kulpin, Valery Borovtsov, and Anar Zhunusbekova. "Effect of aerodynamic loads on redistribution of normal reactions of quarry dump trucks tires." E3S Web of Conferences 174 (2020): 03018. http://dx.doi.org/10.1051/e3sconf/202017403018.
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Tires of quarry dump trucks occupy one of the leading places in the item of costs for motor transport, as they are expensive product and at the same time more than half of them do not generate their resource. The causes of premature tires failure are exceeding normal load on them. In turn, the aerodynamic forces effect on the quarry dump truck as one of the influencing factors, is the dynamic redistribution of normal loads on tires and, as a result, affects temperature modes. The determination of the load on the tire under different operating conditions will increase the service life of the tires and avoid early failure. The proposed calculation method of aerodynamic loads and their influence on redistribution of normal mine dump truck tires reactions in dynamics allows to make correction to load modes and control the tires resource, which will lead to more complete use of tires resource.
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Dittmer, Antje, Bernhard Osterwinter, and Daniel Ossmann. "Combined Individual Pitch and Flap Control for Load Reduction of Wind Turbines." Journal of Physics: Conference Series 2767, no. 3 (June 1, 2024): 032022. http://dx.doi.org/10.1088/1742-6596/2767/3/032022.
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Abstract In this paper individual pitch control is combined with trailing-edge flap (TEF) control, both designed as multi-loop proportional-integral-derivative (PID) controllers, to significantly reduce blade damage equivalent loads. OpenFAST NREL 5MW aerodynamics are enhanced with dedicated aerodynamic polars of TEF blade elements. The NREL 5MW model, including the TEF extension, is incorporated into Simulink, and PID controller parameters are optimized in a closed-loop optimization setup. The DEL decrease is confirmed via an extensive simulation campaign using the non-linear wind turbine simulation environment.
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Liu, Yanming, and Yongyi Yang. "The jitter frequency domain of long-span railway cable-stayed bridges considering the influence of pneumatic admittance." Journal of Physics: Conference Series 2553, no. 1 (August 1, 2023): 012076. http://dx.doi.org/10.1088/1742-6596/2553/1/012076.
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Abstract The long-span bridge is highly sensitive to wind loads, and their random vibration response under static wind deformation and fluctuating wind load are relatively complex. The analysis of jitter response has become a key issue in the design. Taking the Hanjiatuo Yangtze River Bridge in the chongqing-lichuan railway as the engineering background, the influence of different aerodynamic admittance functions on the main girder jitter response is studied through frequency domain analysis. The results show that aerodynamic admittance has a great influence on the jitter response. Considering that the jitter displacement response of the aerodynamic admittance function is obviously smaller than the calculated results, the influence of aerodynamic admittance should be considered in the calculation and analysis.
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Schoř, Pavel. "AERODYNAMIC LOAD OF AN AIRCRAFT WITH A HIGHLY ELASTIC WING." Acta Polytechnica 57, no. 4 (September 1, 2017): 272. http://dx.doi.org/10.14311/ap.2017.57.0272.
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In this article, a method for calculation of air loads of an aircraft with an elastic wing is presented. The method can predict a redistribution of air loads when the elastic wing deforms. Unlike the traditional Euler or Navier-Stokes CFD to FEM coupling, the method uses 3D panel method as a source of aerodynamic data. This makes the calculation feasible on a typical recent workstation. Due to a short computational time and low hardware demands this method is suitable for both the preliminary design stage and the load evaluation stage. A case study is presented. The study compares a glider wing performing a pull maneuver at both rigid and and elastic state. The study indicates a significant redistribution of air load at the elastic case.
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Xu, Zhi Qiang, and Jian Huang. "Research on Wind Turbine Blade Loads and Dynamics Factors." Advanced Materials Research 1014 (July 2014): 124–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1014.124.
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Wind turbines consists of three key parts, namely, wind wheels (including blades, hub, etc.), cabin (including gearboxes, motors, controls, etc.) and the tower and Foundation. Wind turbine wheel is the most important part ,which is made up of blades and hubs. Blade has a good aerodynamic shape, which will produce aerodynamic in the airflow rotation, converting wind energy into mechanical energy, and then, driving the generator into electrical energy by gearbox pace. Wind turbine operates in the natural environment, their load wind turbine blades are more complex. Therefore load calculations and strength analysis for wind turbine design is very important. Wind turbine blades are core components of wind turbines, so understanding of their loads and dynamics by which the load on the wind turbine blade design is of great significance.
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Zeng, Xiao-Hui, Jiang Lai, and Han Wu. "Hunting Stability of High-Speed Railway Vehicles Under Steady Aerodynamic Loads." International Journal of Structural Stability and Dynamics 18, no. 07 (July 2018): 1850093. http://dx.doi.org/10.1142/s0219455418500931.
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With the rising speed of high-speed trains, the aerodynamic loads become more significant and their influences on the hunting stability of railway vehicles deserve to be considered. Such an effect cannot be properly considered by the conventional model of hunting stability analysis. To this end, the linear hunting stability of high-speed railway vehicles running on tangent tracks is studied. A model considering the steady aerodynamic loads due to the joint action of the airflow facing the moving train and the crosswind, is proposed for the hunting stability analysis of a railway vehicle with 17 degrees of freedom (DOF). The key factors considered include: variations of the wheel–rail normal forces, creep coefficients, gravitational stiffness and angular stiffness due to the actions of the aerodynamic load, which affects the characteristics of hunting stability. Using the computer program developed, numerical calculations were carried out for studying the behavior of the linear hunting stability of vehicles under steady aerodynamic loads. The results show that the aerodynamic loads have an obvious effect on the linear critical speeds and instability modes. The linear critical speed decreases monotonously as the crosswind velocity increases, and the influences of pitch moment and lift force on the linear critical speed are larger than the other components of the aerodynamic loads.
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Guan, Xin, Hua Dong Wang, Zhi Li Sun, Xiao Guo Bi, and Xu Dong Liu. "Variation of Aerodynamic Load Engineering Analysis during Wind Turbine Run." Applied Mechanics and Materials 291-294 (February 2013): 501–6. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.501.
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In order to improve design reliability of wind turbine, it is needed that calculating method of aerodynamic load during wind turbine run. In paper from the angle of the project, NACA special airfoil of wind turbine is analyzed. Combined with thin-theory, airfoil angle of attack variation is deduced, meanwhile wind turbine actual force is calculated in each blade location point when blade of wind turbine is running based on wind shear theory and tower shadow effect. According to actual condition calculation method is engineering amplified, aerodynamic load calculation method of wind turbine blade is obtained. By this method aerodynamic load which is calculated match with experiment result, it fits better.
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Li, Yonghong, and Ning Qin. "A Review of Flow Control for Gust Load Alleviation." Applied Sciences 12, no. 20 (October 19, 2022): 10537. http://dx.doi.org/10.3390/app122010537.
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Effective control of aerodynamic loads, such as maneuvering load and gust load, allows for reduced structural weight and therefore greater aerodynamic efficiency. After a basic introduction in the types of gusts and the current gust load control strategies for aircraft, we outline the conventional gust load alleviation techniques using trailing-edge flaps and spoilers. As these devices also function as high-lift devices or inflight speed brakes, they are often too heavy for high-frequency activations such as control surfaces. Non-conventional active control devices via fluidic actuators have attracted some attention recently from researchers to explore more effective gust load alleviation techniques against traditional flaps for future aircraft design. Research progress of flow control using fluidic actuators, including surface jet blowing and circulation control (CC) for gust load alleviation, is reviewed in detail here. Their load control capabilities in terms of lift force modulations are outlined and compared. Also reviewed are the flow control performances of these fluidic actuators under gust conditions. Experiments and numerical efforts indicated that both CC and surface jet blowing demonstrate fast response characteristics, capable for timely adaptive gust load controls.
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Gao, Liang, Jian Xin Liu, and Miao Liu. "Experimental Study of Static Aerodynamic Coefficients of Bridge Section." Advanced Materials Research 301-303 (July 2011): 780–84. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.780.
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With HK-Zhuhai-Macau Bridge as the engineering background, through the section model wind tunnel test, research into the influence of vibration damping measure to the static aerodynamic coefficients of the structure, so as to seek to improve structural characteristics. The influencing factors of static aerodynamic coefficients including the guide plate position, the central trough opening rate, baluster drafty rate, repair car track position, windbreak, and vehicle. The results show that the changes of the static aerodynamic coefficients directly affect the static wind loads, and the influence of changes of these parameters to the static wind load cannot be ignored.