scholarly journals Methodology for calculating the efficiency of the rudders of the tandem aircraft

2021 ◽  
pp. 11-21
Author(s):  
Illya Bilous ◽  
Illya Kryvohatko ◽  
Yurii Yakovlev
Keyword(s):  
Wind Tunnel ◽  
Rapid Development ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Experiment ◽  
Wind Tunnels ◽  
Analysis Tool ◽  
It Impacts ◽  
Characteristics Analysis ◽  
The Stability

As of recent rapid development in the field of UAVs, unusual aerodynamic practices can be used, for example, the tandem scheme. In early planning stages, it’s important to evaluate aerodynamic characteristics of the chosen scheme and to approximate its balancing losses, as it impacts the stability and controllability of the craft. The most effective way of aerodynamic characteristics analysis is done using wind tunnels. However, it requires considerable investments in both financial terms and time, when designing the model, conducting the experiment and processing the results. Because of that, it’s worthwhile to consider the simple CFD calculations (XFOIL). This paper calculates aerodynamic characteristics of a tandem-scheme based “A-8” aircraft using XFLR5 analysis tool with the results compared to a real wind tunnel experiment. The overall conclusion of the paper is a recommendation to consider XFLR5 for early planning stages for advanced balancing losses calculation approximation.

Model Test Techniques Developed to Investigate the Wind Heeling Characteristics of Sailing Vessels and Their Response to Gusts

1991 ◽  
Author(s):  
Barry Deakin
Keyword(s):  
Wind Tunnel ◽  
Model Test ◽  
Wind Tunnels ◽  
Stability Assessment ◽  
Tunnel Floor ◽  
The Stability ◽  
Scaled Models ◽  
Scale Data ◽  
Heeling Moment ◽  
Gust Response

During the development of new stability regulations for the U.K. Department of Transport, doubt was cast over many of the assumptions made when assessing the stability of sailing vessels. In order to investigate the traditional methods a programme of work was undertaken including wind tunnel tests and full scale data acquisition. The work resulted in a much improved understanding of the behaviour of sailing vessels and indeed indicated that the conventional methods of stability assessment are invalid, the rules now applied in the U.K. being very different to those in use elsewhere. The paper concentrates on the model test techniques which were developed specifically for this project but which will have implications to other vessel types. The tests were of two kinds: measurement of the wind forces and moments on a sailing vessel; and investigation of the response of sailing vessels to gusts of wind. For the force and moment measurements models were mounted in a tank of water on a six component balance and tested in a large boundary layer wind tunnel. Previous tests in wind tunnels have always concentrated on performance and the heeling moments have not normally been measured correctly. As the measurements of heeling moment at a range of heel angles was of prime importance a new balance and mounting system was developed which enabled the above water part of the vessel to be modelled correctly, the underwater part to be unaffected by the wind, and the interface to be correctly represented without interference. Various effects were investigated including rig type, sheeting, heading, heel angle and wind gradient. The gust response tests were conducted with Froude scaled models floating in a pond set in the wind tunnel floor. A mechanism was installed in the tunnel which enabled gusts of various characteristics to be generated, and the roll response of the models was measured with a gyroscope. These tests provided information on the effects of inertia, damping, rolling and the characteristics of the gust. Sample results are presented to illustrate the uses to which these techniques have been put.

Investigation of rapid manufacturing technology with ABS material for wind tunnel models fabrication

2012 ◽  
Vol 32 (8-9) ◽  
pp. 575-584 ◽  
Author(s):  
Saeed Daneshmand ◽  
Cyrus Aghanajafi ◽  
Hossein Shahverdi
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Raw Materials ◽  
Dimensional Accuracy ◽  
Aerodynamic Characteristics ◽  
Wind Tunnels ◽  
Rapid Manufacturing ◽  
Material Strength ◽  
Wind Tunnel Testing ◽  
Tunnel Testing

Abstract Nowadays, several procedures are used for manufacturing wind tunnel models. These methods include machining, casting, molding and rapid prototyping. Raw materials such as metals, ceramics, composites and plastics are used in making these models. Dimension accuracy, surface roughness and material strength are significant parameters which are effective in wind tunnel manufacturing and testing. Wind tunnel testing may need several models. Traditional methods for constructing these models are both costly and time consuming. In this research, a study has been undertaken to determine the suitability of models constructed using rapid manufacturing (RM) methods for use in wind tunnel testing. The aim of this research is to improve the surface roughness, dimensional accuracy and material strength of rapid manufacturing models for testing in wind tunnels. Consequently, the aerodynamic characteristics of three models were investigated and compared. The first model is made of steel, the second model from FDM-M30, and the third model is a hybrid model. Results show that metal models can be replaced by hybrid models in order to measure aerodynamic characteristics, reduce model fabrication time, save fabrication cost and also to verify the accuracy of aerodynamic data obtained in aerospace industry.

A Modular Wing-Tail Airplane Configuration for the Educational Wind Tunnel Laboratory

2004 ◽  
Author(s):  
B. Terry Beck
Keyword(s):  
Wind Tunnel ◽  
Rapid Prototyping ◽  
Calibration Procedure ◽  
Aerodynamic Characteristics ◽  
Wind Tunnels ◽  
Small Scale ◽  
Pitching Moment ◽  
Gravity Effects ◽  
Basic Parameters ◽  
Rapid Prototyping System

An innovative modular airplane configuration has been developed for use in small-scale educational wind tunnels. The “airplane” consists of an interchangeable wing and horizontal tail configuration that mounts on a conventional wind tunnel electronic balance (“sting”) to facilitate measurements of normal force, axial force and longitudinal pitching moment. From these basic parameters, the total lift, total drag, and resultant airplane pitching moment can be deduced, along with the location of the aerodynamic center of the total airplane. Using known wing planform and airfoil shapes facilitates comparison of the total airplane aerodynamic characteristics with those predicted from the known characteristics of the separate wing and horizontal tail. In particular, the aerodynamic center of the simplified airplane configuration can be determined, along with the effect that downwash on the tail has on longitudinal stability of the airplane. Included in the paper is a description of the calibration procedure for the modular “sting” mount. This procedure accounts for an offset “line of action” for aerodynamic forces, as well as offset center of gravity effects. In conjunction with this same test setup, an available Rapid Prototyping system has been used to manufacture the test sections (separate wing and tail) for use in the wind tunnel, and in particular, in the modular wing-tail assembly. This provides tremendous flexibility in the types of wing-tail assemblies that can be investigated experimentally using the same module. The relatively inexpensive prototyping procedure also provides the capability for students to design and test their own configurations. Furthermore, the precision manufacturing capability of the Rapid Prototyping system guarantees reliable reproduction of virtually any desired aerodynamic planform and airfoil shape.

scholarly journals Aerodynamic Characteristics Analysis and External Trajectory Simulation of High-speed Cross-media Water Entry Projectile

2021 ◽  
Vol 2079 (1) ◽  
pp. 012023
Author(s):  
Xu-Tuo Ding ◽  
Shi-Ji Li ◽  
Song-Jiang Peng ◽  
Jin Wei
Keyword(s):  
High Speed ◽  
Initial Conditions ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Water Entry ◽  
Aerodynamic Coefficients ◽  
Cross Media ◽  
Characteristics Analysis ◽  
The Stability ◽  
Trajectory Equation

Abstract The aerodynamic characteristics of a water entry projectile is studied. The aerodynamic coefficients at different Mach numbers and different attack angles are given through CFD numerical simulation, and the stability analysis is carried out. The results show that the projectile with the current shape meets the static stability requirements. Based on the aerodynamic coefficients obtained, the projectile flight trajectory equation is established to obtain the trajectory at different emissive angles. Finally, the trajectory parameters with the range of 5 km were used as the initial conditions for the simulation of high-speed water entry projectile, and the process of projectile entry with small angle was simulated. The simulation results show that the projectile sails smoothly when entering the water, the trajectory is straight, there is no ricochet phenomenon, which has a good water entry stability.

scholarly journals Serve Ball Trajectory Characteristics of Different Volleyballs and Their Causes

2021 ◽  
Vol 11 (19) ◽  
pp. 9269
Author(s):  
Takehiro Tamaru ◽  
Masaki Hiratsuka ◽  
Shinichiro Ito
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Force Measurement ◽  
Lateral Force ◽  
Aerodynamic Characteristics ◽  
Flight Distance ◽  
Wind Tunnels ◽  
Fluid Force ◽  
Precise Control ◽  
Ball Trajectory

A floater serve in volleyball is a technique of serving a non-rotating or low-rotating ball, which is difficult to return because the flight path of the ball changes irregularly. On the other hand, the randomness of the trajectory makes it difficult for the ball to fall on the target. Players are required to serve taking into account the variability of the trajectory. In previous studies using wind tunnels, it was shown that aerodynamic characteristics such as drag force and lateral force applied to the ball vary depending on the type of ball and the orientation of the panel. Therefore, in order to control the flight trajectory, it is necessary to understand the aerodynamic characteristics of each ball. Since the velocity of the ball and the fluid force applied to the ball changes during flight, it is important to measure not only the fluid force at a steady state in the wind tunnel but also the actual flight distance of the ball. In this study, to provide valuable information for precise control of floater serves, we measured the drag force applied to the ball in a wind tunnel and the flight distance of the ball using an ejection machine, and clarified the effects of the type of ball and the panel face. In the drag force measurement, the drag force on three types of balls, V200W, MVA200, and FLISTATEC, was measured in the wind speed range of 4 m/s to 30 m/s. In the ejection measurement, the ball flight distances were measured while changing the orientation of the panel using an ejection machine. Basically, the FLISTATEC, MVA200, and V200W, in that order, were more likely to increase the distance and the variability, but it was shown that the drop point could be adjusted slightly by selecting the panel face. This result was also obtained when a human player actually served the ball, indicating the tactical importance of the player consciously controlling the direction of the panel. The tactical importance of the player’s conscious control of the direction of the panel was demonstrated. We also proposed receiver positions that would be effective based on the characteristics of each ball.

scholarly journals Wind-tunnel experiment on aerodynamic characteristics of a runner using a moving-belt system

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Tatsuya Inoue ◽  
Takafumi Okayama ◽  
Takahiro Teraoka ◽  
Satoshi Maeno ◽  
Katsuya Hirata
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Experiment ◽  
Belt System

Numerical Simulation and Wind Tunnel Experiment of the Aerodynamic Characteristics of a Formula Student Racing Car

2013 ◽  
Vol 774-776 ◽  
pp. 460-464
Author(s):  
Guo Xin Wang ◽  
Yinuo Hu ◽  
Ting Ting Xu ◽  
Ze Fei Li ◽  
Bo Yang
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Numerical Simulations ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Experiment ◽  
Rear Wing ◽  
Front Wing ◽  
The Difference

This research used CFD softwares to simulate the downforce generated with the airfoil set to different height, and also analyzed the difference on the downforce when the airfoil is set on the racing car. Several pairs of front wing (FW) and rear wing (RW) of different ground clearances were chosen during the wind tunnel experiment and the results were compared with those of the numerical simulations. With the results of the simulations as well as the experiment, an appropriate solution of the ground clearances of the FW and RW for different kinds of race is provided.

scholarly journals PENELITIAN DAN PENGUJIAN KARAKTERISTIK AERODINAMIKA BOM LATIH PERCOBAAN BLP-500 DAN BLP 25

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Agus Aribowo ◽  
Sulistyo Atmadi ◽  
Yus Kadarusman Markis
Keyword(s):  
Wind Tunnel ◽  
Analytical Calculation ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Supersonic Wind Tunnel ◽  
Centre Of Gravity ◽  
The Stability

Research and aerodynamic testing of BLP-500 and BLP-25 have been conducted in both subsonic and supersonic wind tunnel. Aerodynamic characteristics such as Cl, Cd, and Cm for these types of bomb we obtained. By knowing the aerodynamic characteristics, the stability and trajectory of the bomb can be determined. Both analytical calculation and real tests in the wind tunnel were performed and compared. The results showed that for its static stability, the location of the centre of gravity of BLP-500 and BLP-25 to be less than 115.1 cm and 31.9 cm respectively.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

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