scholarly journals MODELLING THE HELICOPTER ROTOR AERODYNAMICS AT FORWARD FLIGHT WITH FREE WAKE MODEL AND URANS METHOD

Aviation ◽  
2020 ◽  
Vol 24 (4) ◽  
pp. 149-156
Author(s):  
Yuri Ignatkin ◽  
Pavel Makeev ◽  
Sergey Konstantinov ◽  
Alexander Shomov
Keyword(s):  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Helicopter Rotor ◽  
Force Coefficient ◽  
Ansys Fluent ◽  
Rotor Aerodynamics ◽  
Horizontal Flight ◽  
Wake Model ◽  
Unsteady Characteristics ◽  
Free Wake

The presented work is dedicated to the numerical study of the aerodynamic characteristics of the helicopter rotor. Two approaches to modeling of the rotor are applied: the free wake model developed by the Authors with using steady airfoil characteristics and the Unsteady RANS method based on the Ansys Fluent software. The modes of hovering and horizontal flight in the range of advancing ratio μ = (0-0.45) are considered. The shapes of the rotor wake, the distributions of the normal force coefficient and the fields of inductive velocities for all considered flight modes are calculated. For a particular case with μ = 0.25 there is a comparison with experimental data. The time needed for calculation of the applied methods is estimated. Accuracy of the used methods in the framework of the solved task is analysed with taking into account used models assumptions. It is shown that in the range of μ = (0-0.25) the free wake model provides a fast and reliable calculation of the aerodynamic characteristics of the helicopter rotor. For values of μ > 0.35 it is necessary to take into account the unsteady characteristics of the airfoil.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

An Experimental and Numerical Investigation of the Effect of Combustor-Nozzle Platform Misalignment on Endwall Heat Transfer at Transonic High Turbulence Conditions

2016 ◽  
Author(s):  
A. Arisi ◽  
D. Mayo ◽  
Z. Li ◽  
W. F. Ng ◽  
H. K. Moon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Horseshoe Vortex ◽  
Aerodynamic Characteristics ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Vortex System ◽  
Ansys Fluent ◽  
Heat Transfer Augmentation ◽  
Exit Mach Number

A detailed experimental and numerical study has been conducted to investigate the endwall heat transfer characteristics on a nozzle platform that has been misaligned with the combustor exit, resulting in a backward facing step at the nozzle inlet. The study was carried out under transonic engine representative conditions with an exit Mach number of 0.85 (Reexit = 1.5 × 106), and an inlet turbulence intensity of 16%. A transient infrared thermography technique coupled with endwall static pressure ports, were used to map the endwall surface heat transfer and aerodynamic characteristics respectively. A numerical study was also conducted by solving the steady state Reynolds Averaged Navier Stokes (RANS) equations using the commercial CFD solver ANSYS Fluent v.15. The numerical results were then validated by comparing to experiment data and good agreement was observed. The results reveal that the classical endwall secondary flows (endwall crossflows, horseshoe and passage vortices) are weakened and a unique auxiliary vortex system develops within the passage and interacts with the weakened horseshoe vortex. It is observed that heat transfer in the first half of the passage endwall is heavily influenced by this auxiliary vortex system. Heat transfer augmentation of between 15% and 40% was also observed throughout the NGV endwall. Furthermore, the auxiliary vortex system results in a delayed cross-passage migration of the horseshoe vortex which consequently results in large lateral gradient in heat transfer downstream of the throat.

Aerodynamic Analysis of the Helicopter Rotor Using the Time-Domain Panel Method

2009 ◽  
Author(s):  
Seawook Lee ◽  
Leesang Cho ◽  
Hyunmin Choi ◽  
Jinsoo Cho
Keyword(s):  
Time Domain ◽  
Numerical Technique ◽  
Aerodynamic Characteristics ◽  
Panel Method ◽  
Helicopter Rotor ◽  
Aerodynamic Analysis ◽  
Aerodynamic Performances ◽  
Long Time ◽  
Wake Model ◽  
The Time Domain

Recently, aerodynamic analysis of the helicopter rotor using computational fluid dynamics (CFD) is widely carried out with high accuracy. But, it is very long time to calculate aerodynamic performances and it is difficult to simulate the wake shape of the helicopter rotor using CFD analysis. In this research the time-domain panel method, which uses a numerical technique based on the piecewise constant source and doublet singularities, is applied to the analysis and prediction of the unsteady aerodynamic characteristics of helicopter rotor in a potential flow. And the free wake model is used for wake simulation. The results of present method are compared with the results of experiment of a helicopter rotor in hover and in forward flight. Results show good agreement with the experimental results.

scholarly journals Numerical study of the aerodynamic characteristics of an axisymmetric profile of an optimized shape

2021 ◽  
pp. 5-11
Keyword(s):  
Gas Flow ◽  
Aerodynamic Drag ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Inviscid Gas ◽  
Speed Up ◽  
The Cost ◽  
Different Characteristics

Today, one of the important and urgent tasks of the aerodynamics science is the study and op-timization of aerodynamic characteristics of optimized profile shapes in a gas flow. This problem arises in the design of aircraft and various vessels and is associated with a rational choice of profile shape for a large number of different characteristics and, in particular, in terms of aerodynamic drag. In this paper, consider methods for optimizing an axisymmetric aerodynamic profile in a sta-tionary laminar inviscid gas flow at different angles of attack. The proposed method of solv-ing such a problem of optimization and numerical study of aerodynamic characteristics of the described body in the flow is relevant due to the complexity of its solution, for example, by traditional methods based on the Navier-Stokes system of differential equations. Experi-mental methods are based on expensive and time-consuming tools that do not guarantee find-ing the optimum. Such a computing tool as Ansys Fluent is well suited for solving such prob-lems of hydroaerodynamics and allows not only to speed up and reduce the cost of the compu-tational experiment, but also to increase the efficiency of its implementation. The article describes the process of finding the optimum, which reduces to minimizing the drag force of the previously described axisymmetric profile. A description is also given of the wing

scholarly journals On the aerodynamic interactions analysis between the main rotor and the helicopter fuselage

10.29007/3m41 ◽  
2020 ◽  
Author(s):  
Thanh Dong Pham ◽  
Anh Tuan Nguyen ◽  
Ngoc Thanh Dang ◽  
Vu Uy Pham
Keyword(s):  
Aerodynamic Characteristic ◽  
Vortex Lattice ◽  
Aerodynamic Characteristics ◽  
Main Rotor ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Wake Model ◽  
Helicopter Main Rotor ◽  
Flight Regimes ◽  
Free Wake

This paper develops a numerical method that is capable of analyzing the aerodynamic characteristic of the helicopter main rotor in consider the influence of fuselage. The method is based on an unsteady nonlinear vortex-lattice method that can be used to simulate the interactions among the helicopter components efficiently. To clarify the effect of the main rotor-fuselage interaction, the aerodynamic characteristics of the main rotor in consider the influence of fuselage is determined along with those of the combined main rotor-fuselage system. The paper also shows the velocity field and free wake model in several flight regimes. The fuselage is modeled as a streamlined object, which is discretized into the system of quadrilateral vortex panels. The no-penetration boundary condition is satisfied on the fuselage surface, and no vorticity is shed from the fuselage. The results obtained in this paper are validated against experimental data and some from previous numerical methods.

scholarly journals Application of pressure head theory to determine the aerodynamic characteristics of the helicopter main rotor

2021 ◽  
Vol 273 ◽  
pp. 07026
Author(s):  
Andrey Reshenkin ◽  
Sergey Lisin ◽  
Oleg Zimovnov ◽  
Roman Mishchenko
Keyword(s):  
Statistical Data ◽  
Pressure Head ◽  
Aerodynamic Characteristics ◽  
Helicopter Rotor ◽  
Experimental Setup ◽  
Main Rotor ◽  
System A ◽  
Response Coefficient ◽  
Horizontal Flight ◽  
Helicopter Main Rotor

A method is proposed for calculating main aerodynamic characteristics of the main rotor of the Mi-26 helicopter: a lift, a reactive moment, a required power of the propulsion system, a speed of the inductive air flow, a throttle response coefficient, a speed of the horizontal flight. This method based on the pressure propeller theory. The parameters of the Mi-26 helicopter and the propeller of the experimental setup calculated according to the pressure theory of the main rotor are experimentally confirmed. The percentage of the discrepancy between the statistical data on the aerodynamic characteristics of the Mi-26 helicopter rotor calculated with the pressure theory does not exceed 1.5%.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

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