Straight Wing Research Articles

直線翼垂直軸風車における高効率で自己起動性に優れた翼型の数値的研究

直線翼垂直軸風車における高効率で自己起動性に優れた翼型の数値的研究

БЕЗПІЛОТНИЙ ЛІТАЛЬНИЙ АПАРАТ ІЗ ПРЯМИМ ТА АРОЧНИМ КРИЛОМ

The purpose of this article is to develop a methodology for calculating the aerodynamic computer of the aircraft to straight and arched wings.Сorresponding unmanned aerial vehicle has been considered for the development of methodology. This design is necessary to achieve greater lift force which enables the implementation of a vertical takeoff and landing.Scientific novelty lies in the combination of design already exist-ing of aircraft with arched wings and multicopter, implement-ing vertical takeoff.This article describes a method of computer calculation of aerodynamic-cal characteristics for unmanned aircraft to straight and arched wings. To develop a methodology for the selection of the profile were used, calculation of aerodynamic characteristics for an isolated wing, as well as the construction of the velocity diagrams and overloads for further Designing-of unmanned aircraft to straight and arched wings.According to the calculation results it can be concluded that the subject of the summer-tive device can perform a vertical take-off and landing on nepod-prepara- areas and in urban environments.

Effect of chevrons on the slat noise of straight and swept wings

An experimental study of the airframe noise for small-scale wing models with high-lift devices (slat and flap) is performed. It is shown that installation of chevrons on the lower edge of a slat leads to noise reduction on both straight and swept wings. Simultaneous acoustic and aerodynamic measurements show that chevrons lead to suppression of the slat tonal noise components without significantly affecting the wing aerodynamics.

Parametric Exploration of Wing–Body Junction Flow Using Computational Fluid Dynamics

The wing–body junction flow is investigated parametrically using computational fluid dynamics in an attempt to understand the effects of junction flow on aircraft drag, with a focus on application to large business jet or commercial transport aircraft. A Reynolds-averaged Navier–Stokes computational fluid dynamics methodology is validated against detailed experimental data for a junction flow. Computational fluid dynamics results for a wing with a leading-edge strake (an aerodynamic surface designed to reduce flow separation, thereby reducing aircraft drag) are presented, and the effects of scaling this strake are explored. The effectiveness of the strake on a swept wing is compared to the same for a straight wing. Finally, the results from this parametric study are successfully applied to sizing a leading-edge strake for a commercial transport aircraft. It is demonstrated that a systematic approach, starting with a simple, validated model and building up to a realistic aircraft application, can build confidence in computational fluid dynamics results.

Computational Analysis of Different Shapes of Dimple on Wing

Dimple is a slight indentation in a surface. Dimples create turbulence by creating vortices which delays the boundary layer separation resulting in decrease of drag, increasing aerodynamic efficiency, manoeuvrability and also the angle of stall. The present work focused on the understanding of the effect of dimples on boundary layer separation, lift, drag, critical angle of attack, aerodynamic efficiency of wings. The airfoils without any dimples and with circular dimples as inward and outward on are studied. Types of dimples considered in 3D studies are circular and octagon dimple then computational analysis is done using ANSYS FLUENT CFD software, applying subsonic flow, in three dimensional co-ordinate system. The results are compared with a straight wing without dimples. Then suggestions and conclusions are made.

Calculation and Analysis on Stealth and Aerodynamics Characteristics of a Medium Altitude Long Endurance UAV

This paper seeks to calculate and analyze the stealth and aerodynamics characteristics of a medium altitude long endurance (MALE) UAV. Firstly, geometry model of the UAV was established according its technical parameters by three-dimensional modeling software. In terms of electromagnetics analysis, the physical optics (PO) and the method of equivalent currents (MEC) were used as the numerical computation method, and its feasibility was verified by experiment. The main radar scattering source, scattering characteristics, polarization characteristics and RCS level were analyzed by the computation of the main components and the whole UAV under the electromagnetic bound S (3GHz) and bound X (10GHz). In terms of fluid analysis, the finite volume method was used to solve Navier-Stokes equations and the Spalart-Allmaras (S-A) turbulence model was applied to simulate the turbulence. The aerodynamics characteristics of lift, drag and pitch in the cruise state were calculated. The final result shows: the aerodynamic layout of high aspect ratio and approximate straight wing has good aerodynamic performance of high lift-drag ratio. The high aerodynamic efficiency of UAV makes for investigation or carrying out other tactical assignment with long endurance; however, the aerodynamic layout has the disadvantage in the stealth performance. Big leading edge radius of the low-speed aero foil and low sweptback angle of wing (and empennage) has mirror reflection, which make up of the important scattering source in the front direction of UAV. Large radius of curvature surface and small angle plane of fuselage has high scattering level in the side direction of UAV. These results may help the stealth design and research of UAV.

Validation of UAV Wing Structural Model for Finite Element Analysis

Finite element method is increasingly used in the analysis of aircraft structures, including Unmanned Aerial Vehicles (UAVs). The structural model used for finite element analysis however needs to be validated in order to ensure that it correctly represents the physical behaviour of the actual structure. In this work, a case study of a straight, unswept and untapered wing structure made of composite material subjected to aerodynamic loading was modelled and analysed using finite element method. Four-noded, reduced integration shell elements were used, with structural components attached by adhesive joints modelled using tied surface constraints. For the validation process an experimental set-up of the actual wing was loaded using sandbags to simulate the aerodynamic loads. The deflection of the wing at three key locations were obtained and compared between both methods. It was found that the difference between both results ranges between 0.3% (at the tip) to 36.1% (near the root, for small deflections).

Aerodynamic performance analysis of a non-planar C-wing using CFD

The aircraft is the second fastest means of transport. One of the most important necessities of an aircraft is the air flow over the wings to produce lift. Wing is a structure attached to the fuselage of the aircraft. Lift is an aerodynamic force which is counteracted by drag. In air transport, the cost of operation per each person/unit is higher than in the other transport because of lower passenger/load carrying capacity. One of the best ways to reduce the cost among such factors is increasing the capacity of the airplane. And this can be increased by weight carrying or lifting capacity of the airplane. Lift is controlled by the free stream flow over the wing body (main lifting body) and speed of the flow that produce drag. Most aircraft are monoplanes having one-wing structure for providing lift. Biplanes (two wings) or triplanes (three wings) were popular in the past. Due to inefficiency of the biplane and triplane (used in past days), monoplanes are in present use. To increase the efficiency of the monoplane configuration, ‘C-wing’ configuration is presented in this article. The aim is to prove, at all angles of attack, the C-wing will produce higher (L/D) ratio than straight wing for the same wetted surface area. The work undertaken here is to study the aerodynamic performance of a non-planar C-wing. This project concentrates on comparison between straight wing and C-wing with regard to characteristics like drag, stall.

Experimental Studies of the Effect of Vortex Disturbances on the Flow Around the Wing Model at Low Reynolds Numbers

Results of experimental investigations in subsonic wind tunnels, which studied the impact of artificial forcing on the flow in the boundary layer of straight wing model were described. The feature of this work is the use of such locally impact that can change the general flow pattern. The influences of the angle of attack, free stream turbulence level, and wake behind thin thread on the flow near the wing profile were studied at this paper. The method of oil-film based on titanium dioxide was applied for flow visualization, also hot-wire measurements were used. The obtained results were analyzed with the aim of finding the most efficient ways of vortex control to the flow

Analysis of the Bionic Wing's Aerodynamic Performance

According to a certain type of flying in the no imitation gull wing design straight wing with man. Then the bionic wing and conventional airfoil are simulated, and compared the two kinds of wing aerodynamic parameters. The study found, hale no flow man-machine bionic wing design can effectively improve the wing, reduce the upper wing surface flow separation, reduce the lift loss, reduce the pressure drag, improve the lift drag ratio of the wings. In this paper, the simulation results for the design of the UAV wing provides certain reference.

A novel stochastic collocation method for uncertainty propagation in complex mechanical systems

This paper presents a novel stochastic collocation method based on the equivalent weak form of multivariate function integral to quantify and manage uncertainties in complex mechanical systems. The proposed method, which combines the advantages of the response surface method and the traditional stochastic collocation method, only sets integral points at the guide lines of the response surface. The statistics, in an engineering problem with many uncertain parameters, are then transformed into a linear combination of simple functions’ statistics. Furthermore, the issue of determining a simple method to solve the weight-factor sets is discussed in detail. The weight-factor sets of two commonly used probabilistic distribution types are given in table form. Studies on the computational accuracy and efforts show that a good balance in computer capacity is achieved at present. It should be noted that it’s a non-gradient and non-intrusive algorithm with strong portability. For the sake of validating the procedure, three numerical examples concerning a mathematical function with analytical expression, structural design of a straight wing, and flutter analysis of a composite wing are used to show the effectiveness of the guided stochastic collocation method.

AFFECTING EACH OF RIDGER FURROW OPENER PARAMETERS AND PLANTING METHODS ON WATER USE EFFICENCY AND SUGAR BEET YIELD

Design parameters of the ridger furrow opener directly affecting the furrow profile characteristics and the amount of applied water. Furrow-bed irrigation technique is usually used for water conservation, efficient fertilizer use and many other benefits. This study is to evaluate the impact of design parameters of the ridger furrow opener and planting methods on sugar beet yield and water use efficiency. Therefore, field experiments are conducted to (i) investigate the effects of share rake angles (20o, 25o and 30o), opener wing angles (35o and 45o) and wing shape configurations (straight and curved) on the furrow profile characteristics, transverse scattering, draft force, and (ii) evaluate planting methods (i.e. ridges with 50 cm rows spacing and pair of rows on bed with 30, 35 and 40 cm rows spacing), the wing shape and angles on the emergence, sugar percentage, root and sugar yield, applied water and water use efficiency. The results showed that the curved shape and the wing angle of 45o produced wider furrows than those produced by the straight shape and 35o wing angle. Minimum transverse scattering is associated with the curved wing, wing angle of 35o and share rake angle of 20o. Increasing the share rake and wing angles increased the required draft force. The highest average values of root and sugar yields have been achieved at beet planting in beds with 30 cm rows spacing flowed by beds with 35 and 40 cm rows spacing, respectively. The lowest value of the water use efficiency is achieved at planting on ridges compared to the other planting methods. The maximum emergence percentage, root and sugar yields, sugar percentage and water use efficiency are associated with a wing angle of 45o and the curved wing shape.

AFFECTING THE DESIGN PARAMETERS OF RIDGER FURROW OPENER AND PLANTING METHODS ON SUGAR BEET YIELD AND WATER USE EFFICENCY

Design parameters of the ridger furrow opener directly affecting the furrow profile characteristics and the amount of applied water. Furrow-bed irrigation technique is usually used for water conservation, efficient fertilizer use and many other benefits. This study was to evaluate the impact of design parameters of the ridger furrow opener and planting methods on sugar beet yield and water use efficiency. Therefore, field experiments were conducted to (i) investigate the effects of share rake angles (20o, 25o and 30o), opener wing angles (35o and 45o) and wing shapes (straight and curved) on the furrow profile characteristics, transverse scattering, draft force, and (ii) evaluate planting methods (i.e. ridges with 50 cm rows spacing and pair of rows on bed with 30, 35 and 40 cm rows spacing), the wing shape and angles on the percentage of emergence, sugar percentage, root and sugar yield, applied water and water use efficiency. The results showed that the curved shape and the wing angle of 45o produced wider furrows than those produced by the straight shape and 35o wing angle. Minimum transverse scattering was associated with the curved wing, wing angle of 35o and share rake angle of 20o. Increasing the share rake and wing angles increased the required draft force. The highest average values of root and sugar yields could be achieved by planting beet in beds with 30 cm rows spacing flowed by beds with 35 and 40 cm rows spacing, respectively. The lowest value of the water use efficiency was achieved by planting on ridges compared to the other planting methods. The maximum emergence percentage, root and sugar yields, sugar percentage and water use efficiency were associated with a wing angle of 45o and the curved wing shape.

Numerical investigation of unsteady vortex breakdown past 80°/65° double-delta wing

An improved delayed detached eddy simulation (IDDES) method based on the k-ω-SST (shear stress transport) turbulence model was applied to predict the unsteady vortex breakdown past an 80°/65° double-delta wing (DDW), where the angles of attack (AOAs) range from 30° to 40°. Firstly, the IDDES model and the relative numerical methods were validated by simulating the massively separated flow around an NACA0021 straight wing at the AOA of 60°. The fluctuation properties of the lift and pressure coefficients were analyzed and compared with the available measurements. For the DDW case, the computations were compared with such measurements as the mean lift, drag, pitching moment, pressure coefficients and breakdown locations. Furthermore, the unsteady properties were investigated in detail, such as the frequencies of force and moments, pressure fluctuation on the upper surface, typical vortex breakdown patterns at three moments, and the distributions of kinetic turbulence energy at a stream wise section. Two dominated modes are observed, in which their Strouhal numbers are 1.0 at the AOAs of 30°, 32° and 34° and 0.7 at the AOAs of 36°, 38° and 40°. The breakdown vortex always moves upstream and downstream and its types change alternatively. Furthermore, the vortex can be identified as breakdown or not through the mean pressure, root mean square of pressure, or even through correlation analysis.

Static Aeroelastic Response of Wing-Structures Accounting for In-Plane Cross-Section Deformation

In this paper, the aeroelastic static response of flexible wings with arbitrary cross-section geometry via a coupled CUF-XFLR5 approach is presented. Refined structural one-dimensional (1D) models, with a variable order of expansion for the displacement field, are developed on the basis of the Carrera Unified Formulation (CUF), taking into account cross-sectional deformability. A three-dimensional (3D) Panel Method is employed for the aerodynamic analysis, providing more accuracy with respect to the Vortex Lattice Method (VLM). A straight wing with an airfoil cross-section is modeled as a clamped beam, by means of the finite element method (FEM). Numerical results present the variation of wing aerodynamic parameters, and the equilibrium aeroelastic response is evaluated in terms of displacements and in-plane cross-section deformation. Aeroelastic coupled analyses are based on an iterative procedure, as well as a linear coupling approach for different free stream velocities. A convergent trend of displacements and aerodynamic coefficients is achieved as the structural model accuracy increases. Comparisons with 3D finite element solutions prove that an accurate description of the in-plane cross-section deformation is provided by the proposed 1D CUF model, through a significant reduction in computational cost.

Wing Structural Design of a High Altitude Long Endurance Solar-Powered Platform

The solar-powered platform has great application prospects with its unique characteristics of high cruising altitude and long endurance. This paper presents a high-aspect-ratio long straight composite wing structure. A 3D FEM model is used to study the mechanical performance of the wing under gust, by applying nonlinear analytical method. The wing optimization is focused on high stiffness and light weight. A wing structure of feasible strength and stiffness is obtained. Through analysis, several engineering conclusions are obtained. In addition, the instability features of the main spar are included as well.

Control and System Integration of a Small Vertical-Axis Wind Rotor Coupled a Generator Having Two Windings

Increase in the efficiency of a small vertical-axis wind turbine (VAWT) elevates its potential that compares with a horizontal-axis wind turbine (HAWT). The efficiency does not only depend on the power coefficient of the wind rotor but also on the efficiency of the generator. A permanent magnet synchronous generator having two windings keeps high efficiency in both of low rotor speed regime and high rotor speed regime. To maximize the electricity output of the VAWT, this study directly coupled a generator having 1kW winding and 3kW winding with a straight wing vertical-axis wind rotor as a 4kW VAWT. Meanwhile, system integration and control systems of the wind power system were developed to make sure the operation and the safety of the VAWT. The average efficiency of the wind power system is 0.32 through field tests. The results demonstrated that the small VAWT has the same potential in comparison with two small HAWTs via using the electrical generator having two windings.

Performance of Straight Wing Vertical Axis Wind Turbine in Shear Flow near a Porous Fence

Performance of Straight Wing Vertical Axis Wind Turbine in Shear Flow near a Porous Fence

무인헬기 부착용 원심식 볍씨 살포 장치에 관한 연구

Purpose: While an unmanned helicopter has been extensively used for spraying chemicals on agricultural crops, its low utilization (two months per year from July to August) has recently become an issue. This study aimed to increase the utilization of the unmanned helicopter. The centrifugal rice seeder, a mounting device for rice seeding for unmanned helicopter was developed and assessed its performance. Methods: The concept of the centrifugal spraying device was to obtain design criteria for centrifugal distribution. Four types of blade shapes namely straight, curved, straight wing and curved wing were developed and used. The rotational speed of the blades was tested at 1,000, 1,200 and 1,400 rpm. Results: The blade shapes, rotational blade speed and angle of trajectory were theoretically analyzed and results were validated with a series of laboratory experiments. Conclusions: The curved wing blades provided the distribution uniformity (DU) at 1,200rpm of rotational speed and 60 degree of seed drop point. The spray uniformity of 4.2% was also achieved.

Based on Imitation Seagull Airfoil UVA Wing Numerical Simulation

Wing aircraft is one of the major components to generate lift, in today's energy shortage, design the high lift-to-drag ratio wing is the goal pursued by, The author in the exploration of bionic airfoil aerodynamic characteristics on the basis of, which will be applied to straight wing design so as to improve the aerodynamic performance of aircraft.Our research mainly includes two aspects: first, the use of imitation seagull airfoil and NACA4412 airfoil are designed into the straight wing. The use of FLUENT software in Re=300000condition carries on the numerical simulation results show that the ratio of gull wing airfoil than NACA4412 lift coefficient increased by 13%, while the lift to drag ratio,is improved by 46.83%. Then, using the similarity principle, the wing scale, was tested in a wind tunnel test, the results obtained with the simulation are consistent. Airfoil design for the design of high performance wing opened a new way.