New Methodology for the Calculation of Aerodynamic Coefficients on ATR-42 Scaled Model With Neural Network – EGD Method

2014 ◽  
Author(s):  
A. B. Mosbah ◽  
R. Botez ◽  
T. M. Dao
Keyword(s):  
Control System ◽  
Mach Number ◽  
Experimental Tests ◽  
Aerodynamic Performance ◽  
Aerodynamic Coefficients ◽  
Scaled Model ◽  
Moment Coefficient ◽  
Pressure Distributions ◽  
Flight Parameters

The determination of aerodynamic coefficients such as pressure distributions and aerodynamic coefficients (lift, drag and moment) from the known parameters (angle of attack, Mach number …) in real time is still not achievable easily by methods of numerical analysis in aerodynamics and aeroelasticity domains. For this reason, we propose a flight parameters control system. This approach is based on new optimization methodologies with neural networks (NN) and extended great deluge (EGD). The validation of this new method is realized by experimental tests using a model installed in the wind tunnel to determine the pressure distribution. For lift, drag and moment coefficient, the results of our approach are compared to the XFoil results for different angles of attack and Mach number. The main purpose of this control system is to improve the aircraft aerodynamic performance.

New methodology combining neural network and extended great deluge algorithms for the ATR-42 wing aerodynamics analysis

2016 ◽  
Vol 120 (1229) ◽  
pp. 1049-1080 ◽  
Author(s):  
A. Ben Mosbah ◽  
R.M. Botez ◽  
T.-M. Dao
Keyword(s):  
Control System ◽  
Experimental Tests ◽  
Reynolds Numbers ◽  
Aerodynamic Performance ◽  
Fast Determination ◽  
Wing Model ◽  
Pressure Distributions ◽  
Aerodynamic Parameters ◽  
New Methodologies

ABSTRACTThe fast determination of aerodynamic parameters such as pressure distributions, lift, drag and moment coefficients from the known airflow conditions (angles of attack, Mach and Reynolds numbers) in real time is still not easily achievable by numerical analysis methods in aerodynamics and aeroelasticity. A flight parameters control system is proposed to solve this problem. This control system is based on new optimisation methodologies using Neural Networks (NNs) and Extended Great Deluge (EGD) algorithms. Validation of these new methodologies is realised by experimental tests using a wing model installed in a wind tunnel and three different transducer systems (a FlowKinetics transducer, an AEROLAB PTA transducer and multitube manometer tubes) to determine the pressure distribution. For lift, drag and moment coefficients, the results of our approach are compared to the XFoil aerodynamics software and the experimental results for different angles of attack and Mach numbers. The main purpose of this new proposed control system is to improve, in this paper, wing aerodynamic performance, and in future to apply it to improve aircraft aerodynamic performance.

Study on Numerical Simulation Method of Aerodynamic Performance of High-Speed Train on Bridge

2013 ◽  
Vol 376 ◽  
pp. 312-316 ◽  
Author(s):  
Chao Qun Xiang ◽  
Wen Hua Guo ◽  
Jia Wen Zhang
Keyword(s):  
Static Pressure ◽  
Aerodynamic Performance ◽  
Dynamic Mesh ◽  
Positive Pressure ◽  
Aerodynamic Coefficients ◽  
Force Coefficient ◽  
Rolling Moment ◽  
Velocity Magnitude ◽  
Pressure Distributions ◽  
Mesh Method

The dynamic mesh method that could simulate the actual moving of train was used to calculate the aerodynamic coefficients of train on bridge with wind barriers of various heights, and the static pressure distributions around the train body and velocity magnitude distributions were analyzed, the results computed by dynamic mesh method were compared with that computed by traditional static mesh method. The results show that the aerodynamic coefficients of train and flow field characteristics computed by the two methods agree well under the configuration without wind barriers. However, there is considerable difference between the results computed by the two methods with the installation of wind barriers. It is found that the dynamic mesh method is more reasonable to simulate the aerodynamic coefficients of train with wind barriers by analysis of the contour of static pressure distributions and velocity magnitude distributions. The wind barriers effectively decrease the positive pressure on windward train body and negative pressure on train roof, mainly reduce the side force coefficient, lift force coefficient, rolling moment coefficient. Therefore, the aerodynamic performance of train on bridge under crosswind is improved.

scholarly journals Investigation of the dynamical characteristics of the lower-limbs exoskeleton actuators

2018 ◽  
Vol 161 ◽  
pp. 03008 ◽  
Author(s):  
Andrey Yatsun ◽  
Andrey Karlov ◽  
Andrey Malchikov ◽  
Sergey Jatsun
Keyword(s):  
Control System ◽  
Experimental Determination ◽  
Lower Limb ◽  
Low Cost ◽  
Experimental Tests ◽  
Theoretical Modeling ◽  
Lower Limbs ◽  
Dynamical Characteristics ◽  
Powered Exoskeleton

Authors present results of the theoretical modeling and experimental tests of the low-cost DС- motors, used in lower limb powered exoskeleton. Actuators work in difficult regime and it is important to achieve desired parameters, even for not robust motors. Results give us information and methods and means of experimental determination of the main characteristics of the robot‘s actuators. It gives possibility to tune control system and the whole system to achieve optimal walking regime.

scholarly journals Prediction and Analysis of the Aerodynamic Characteristics of a Spinning Projectile Based on Computational Fluid Dynamics

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Arim Ko ◽  
Kyoungsik Chang ◽  
Dong-Jin Sheen ◽  
Chi-Hoon Lee ◽  
Yongin Park ◽  
...  
Keyword(s):  
Mach Number ◽  
Nonlinear Behavior ◽  
Semiempirical Method ◽  
Aerodynamic Coefficients ◽  
Magnus Force ◽  
Force Coefficient ◽  
Moment Coefficient ◽  
Quadratic Drag ◽  
Spinning Projectile ◽  
Simulation Results

Numerical simulations of a spinning projectile with a diameter of 120 mm were conducted to predict the aerodynamic coefficients, and the CFD results were compared with the semiempirical method, PRODAS. Six coefficients or coefficient derivatives, including zero and the quadratic drag coefficient, lift force coefficient derivative, Magnus force coefficient derivative, overturning moment coefficient, and spinning damping moment coefficient, which are important parameters for solving the equations of motion of the spinning projectile, were investigated. Additionally, the nonlinear behavior of these coefficients and coefficient derivatives were analyzed through the predicted flow fields. The considered Mach number ranges from 0.14 to 1.2, and the nondimensional spinning rate (PD/2V) is set to 0.186. To calculate the coefficient derivative of the corresponding force or moment, additional simulations were conducted at the angle of attack of 2.5 degrees. The simulation results were able to predict nonlinear behavior, the especially abrupt change of the predicted coefficients and derivatives at the transonic Mach number, 0.95. The simulation results, including the skin friction, pressure, and velocity field, allow the characterization of the nonlinear behavior of the aerodynamic coefficients, thus, enabling better predictions of projectile trajectories.

Effects of infrastructure on the aerodynamic performance of a high-speed train

2020 ◽  
pp. 095440972095221
Author(s):  
Ming Wang ◽  
Xiao-Zhen Li ◽  
Jun Xiao ◽  
Hai-Qing Sha ◽  
Qi-Yang Zou
Keyword(s):  
High Speed ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
High Speed Train ◽  
Aerodynamic Coefficients ◽  
Pressure Distributions ◽  
Train Speed ◽  
Truss Bridge ◽  
Flat Ground

The aerodynamic characteristics of typical high-speed train can be affected by the operating infrastructure, which will affect the flow structure around train body. Five different infrastructure scenarios, including no infrastructure, flat ground, embankment, viaduct and truss bridge, are systemically studied. The purpose is to examine the uncertainties of aerodynamic coefficients caused by the infrastructure. Attention is drawn to variations of aerodynamic coefficients at certain yaw angles caused by the changes in crosswind and train speed. The middle car is chosen for quantifying the effects of five infrastructures by using wind tunnel test and numerical simulations, then followed by a detailed study on aerodynamic characteristics of three cars of train running on viaduct. Pressure distributions are also drawn for a better interpretation. Result shows that the uncertainties in aerodynamic coefficients becomes more obvious as the infrastructure gets complex and yaw angles get bigger. The aerodynamic coefficients of three cars with the viaduct scenario show the similar uncertainties, which are mostly affected by the change in crosswind rather than the train speed.

Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet for TBCC

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yunfei Wang ◽  
Huacheng Yuan ◽  
Jinsheng Zhang ◽  
Zhenggui Zhou
Keyword(s):  
Mach Number ◽  
Performance Analysis ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Combined Cycle ◽  
Variable Geometry

Abstract Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet was carried out for tandem scheme turbine-based combined cycle (TBCC) propulsion system. The operation Mach number of the inlet was between 0 and 4. The design point was chosen as Mach number 4.0 in this paper. The determination of external and internal compression and the design method of annular to circle diffuser were illustrated. The inlet was unstart under Ma 3.0 without adjustment. Then, a variable scheme was designed to ensure self-start of the inlet and match the requirement of mass flow rate during the whole flight envelope. And four supports were used to fix the spike. According to the 3D numerical simulations, the total pressure recovery was 0.52 at Ma 4.0 at critical condition and the mass flow rate was consistent with the requirement at different flight Mach number.

Determination of YAV-8B Reaction Control System bleed flow usage

1992 ◽  
Author(s):  
PAUL BORCHERS ◽  
ERNESTO MORALEZ, III ◽  
VERNON MERRICK ◽  
MICHAEL STORTZ ◽  
DAVID EAMES
Keyword(s):  
Control System ◽  
Reaction Control System

scholarly journals The Effect of Process Parameters in Helical Rolling of Balls on the Quality of Products and the Forming Process

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2125 ◽  
Author(s):  
Janusz Tomczak ◽  
Zbigniew Pater ◽  
Tomasz Bulzak
Keyword(s):  
Metal Flow ◽  
Experimental Tests ◽  
Rolling Process ◽  
Helical Rolling ◽  
Forming Process ◽  
University Of Technology ◽  
Quality Of Products ◽  
Skew Rolling

This paper presents selected numerical and experimental results of a skew rolling process for producing balls using helical tools. The study investigates the effect of the billet’s initial temperature on the quality of produced balls and the rolling process itself. In addition, the effect of billet diameter on the quality of produced balls is investigated. Experimental tests were performed using a helical rolling mill available at the Lublin University of Technology. The experiments consisted of rolling 40 mm diameter balls with the use of two helical tools. To determine optimal rolling parameters ensuring the highest quality of produced balls, numerical modelling was performed using the finite element method in the Forge software. The numerical analysis involved the determination of metal flow kinematics, temperature and damage criterion distributions, as well as the measurement of variations in the force parameters. The results demonstrate that the highest quality balls are produced from billet preheated to approximately 1000 °C.

Mechanical Behaviour of CoCrMo Alloy with Si Content

2015 ◽  
Vol 754-755 ◽  
pp. 1017-1022 ◽  
Author(s):  
Petrică Vizureanu ◽  
Mirabela Georgiana Minciună ◽  
Dragoş Cristian Achiţei ◽  
Andrei Victor Sandu ◽  
Kamarudin Hussin
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Testing Machine ◽  
Base Material ◽  
Optical Emission ◽  
Experimental Tests ◽  
Optical Emission Spectrometry ◽  
Emission Spectrometry ◽  
Standard Samples

.The paper present aspects about the obtaining of non-precious dental alloys (type CoCrMo and CoCrMoSi7), the determination of chemical composition by optical emission spectrometry and the experimental tests for determining the tensile strength, made on standard plate samples. The base material used in experiments was a commercial alloy, from CoCrMo system, which belongs to the class of dental non-precious alloys, intended to medical applications. The obtaining of studied alloy was made on arc re-melting installation, under vacuum, type MRF ABJ 900. The process followed to realize a rapid melting, with a maximum admissible current intensity. The samples for tests were obtained by casting in an electric arc furnace, under vacuum, in optimal conditions for melting and solidification and processing by electro-erosion, to eliminate all the disturbing factors which come by processing conditions for the samples. The determination of chemical composition for cobalt based alloys, by optical emission spectrometry, was made on SpectromaxX equipment with spark. The electrical discharge is made with the elimination of an energy quantity, fact which determine plasma forming and light issue. Tensile tests for standard samples, made from cobalt based alloy, was made on Instron 3382 testing machine, and assisted by computer. The obtained results are: elongation, elasticity modulus, tensile strength and offer complete information about the analyzed mechanical properties. For the certitude of obtained experimental results, the tests were made on samples with specific dimensions according ISO 6892-1:2009(E) standard, both for the tensile strength, and also machine operation.

Sign in / Sign up

Export Citation Format

Share Document