Computational Research of the Main Rotor Hover and Vertical Descent States Based on the Nonlinear Blade Vortex Model

Ignatkin, Yu. M.; Makeev, P. V.; Shaidakov, V. I.; Shomov, A. I.

doi:10.3103/s1068799818030121

Cited by 3 publications

(3 citation statements)

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“…Форма следа выстраивается в результате расчета. Рассматриваемый численный метод определения аэродинамических характеристик НВ вертолета прошел широкую апробацию, при которой обоснована достоверность получаемых результатов [8][9][10]13].…”

Section: о методе расчетаunclassified

“…Существуют различные методы расчета винтов винтокрылых летательных аппаратов: с использованием интегральных формул, дисковых и лопастных вихревых теорий и сеточные методы [8][9][10][11][12][13][14]. Данные расчетные исследования проводились с использованием разработанной в ЦАГИ «Программы расчета многовинтовых систем винтокрылых летательных аппаратов различной конфигурации» (MultiRotor VTOL [15]).…”

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Computational studies of the rotors aerodynamic characteristics of multirotor drones

Косушкин

Kritsky

Mirgazov

2021

Naučn. vestn. MGTU GA

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The article presents the results of computational studies of aerodynamic characteristics for unmanned lift-generating multi-rotor drones of various configurations. The distinctive features of rotors flow were characterized. The rotor interaction was evaluated. The computations were based on the nonlinear rotor blade vortex theory in a non-stationary arrangement. The combinations of four, eight (four coaxial) and fourteen two-bladed rotors at velocity V = 100, 150, 200 km/h were considered. Semi-empirical methods were employed to select the rotor angles of attack, rotation speed, blade installation angles and geometric parameters at the given take-off weight for each combination of rotors and flight airspeed. The computations showed that for a four-rotor lift-generating design (quad-rotor), two rotors installed downstream, depending on the velocity due to the mutual effect, have values of the thrust coefficients ≈10...20% less than those of the rotors located upstream. For a coaxial quad-copter, the effect of the upper front rotor on the upper rear rotor is similar to the effect of the front rotors on the rear ones in a four-rotor lift-generating design. The effect of the upper front rotor on the lower rear rotor does not vary in terms of the average thrust value, and variations are only local in nature. The interaction of other rotors is identical to that of the four-rotor version. A fourteen-rotor lift-generating multi-rotor drone has a complex flow pattern, which generates deviance in the thrust coefficients variation with respect to time. Depending on the mode and rotors location, the average rotor thrust coefficient can vary approximately twice. The computations showed that with the similar geometric parameters and kinematics characteristics, rotors thrust is substantially subject to variation, which causes destabilizing moments to a significant degree without additional control input. Thrust pulsations and, respectively, vibrations grow in intensity as the flight airspeed increases. Probably, the right choice of the rotor configuration and the automatic control system can counterbalance thrust surge by so-called "phasing", i.e. selecting an initial azimuth angle for each rotor.

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Section: о методе расчетаunclassified

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Computational studies of the rotors aerodynamic characteristics of multirotor drones

Косушкин

Kritsky

Mirgazov

2021

Naučn. vestn. MGTU GA

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“…Johnson (2005), Ignatkin et al (2018) and Stanisławski (2010), are focused only on investigations of flight of isolated main rotor, and their computational models of flight are based usually on implemented the nonlinear blade vortex model. Based on the same approach, Ignatkin et al (2018) present the computational research on aerodynamic performance of the Mi-8 helicopter main rotor in the hover state and the vertical descent state, including VRSs. The data necessary to validate helicopter-flight-simulation methods or codes may be found in flight training or manoeuvre guides published by rotorcraft manufacturers (Robinson, 2013; Bell, 1999).…”

Section: Introductionmentioning

confidence: 99%

Investigations of the vortex ring state on a helicopter main rotor using the URANS solver

Stalewski

Surmacz

2020

AEAT

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Purpose This paper aims to present the novel methodology of computational simulation of a helicopter flight, developed especially to investigate the vortex ring state (VRS) – a dangerous phenomenon that may occur in helicopter vertical or steep descent. Therefore, the methodology has to enable modelling of fast manoeuvres of a helicopter such as the entrance in and safe escape from the VRS. The additional purpose of the paper is to discuss the results of conducted simulations of such manoeuvres. Design/methodology/approach The developed methodology joins several methods of computational fluid dynamics and flight dynamic. The approach consists of calculation of aerodynamic forces acting on rotorcraft, by solution of the unsteady Reynold-averaged Navier–Stokes (URANS) equations using the finite volume method. In parallel, the equations of motion of the helicopter and the fluid–structure-interaction equations are solved. To reduce computational costs, the flow effects caused by rotating blades are modelled using a simplified approach based on the virtual blade model. Findings The developed methodology of computational simulation of fast manoeuvres of a helicopter may be a valuable and reliable tool, useful when investigating the VRS. The presented results of conducted simulations of helicopter manoeuvres qualitatively comply with both the results of known experimental studies and flight tests. Research limitations/implications The continuation of the presented research will primarily include quantitative validation of the developed methodology, with respect to well-documented flight tests of real helicopters. Practical implications The VRS is a very dangerous phenomenon that usually causes a sudden decrease of rotor thrust, an increase of the descent rate, deterioration of manoeuvrability and deficit of power. Because of this, it is difficult and risky to test the VRS during the real flight tests. Therefore, the reliable computer simulations performed using the developed methodology can significantly contribute to increase helicopter flight safety. Originality/value The paper presents the innovative and original methodology for simulating fast helicopter manoeuvres, distinguished by the original approach to flight control as well as the fact that the aerodynamic forces acting on the rotorcraft are calculated during the simulation based on the solution of URANS equations.

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Numerical investigation of full scale coaxial main rotor aerodynamics in hover and vertical descent

Makeev

Ignatkin

Shomov

2021

Chinese Journal of Aeronautics

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Computational Research of the Main Rotor Hover and Vertical Descent States Based on the Nonlinear Blade Vortex Model

Cited by 3 publications

References 1 publication

Computational studies of the rotors aerodynamic characteristics of multirotor drones

Computational studies of the rotors aerodynamic characteristics of multirotor drones

Investigations of the vortex ring state on a helicopter main rotor using the URANS solver

Numerical investigation of full scale coaxial main rotor aerodynamics in hover and vertical descent

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