Experimental and Numerical Analysis of Repairing a Triangular Shaped Airfoil

2011 ◽  
Author(s):  
F. Etemadi ◽  
M. Mani ◽  
M. Etemadi
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Aerodynamic Characteristics ◽  
Test Model ◽  
Aerodynamic Coefficients

This article investigates the aerodynamic characteristics of repairing the airfoil with triangular damage by the measurement of aerodynamic coefficients improvement. For study of this model “two applied and numerical methods are used”. A full span NACA 641-412 airfoil is considered as test model. Using model is in five schematics: undamaged model, damaged model with upper, lower and full repair model. The used repair sheets are chosen based on the ABDR manuals. Effect of the repair on different shape of damage has performed by the quantity and quality results.

Upon Impact Numerical Modeling of Foam Materials

2017 ◽  
Vol 54 (2) ◽  
pp. 195-202
Author(s):  
Vasile Nastasescu ◽  
Silvia Marzavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Boundary Conditions ◽  
General Character ◽  
Foam Material ◽  
Various Boundary Conditions ◽  
Specific Behaviour

The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

Optimization of the Navy’s three-dimensional mine impact burial prediction simulation model, Impact35, using high-order numerical methods

2021 ◽  
pp. 154851292110286
Author(s):  
Athanasios Donas ◽  
Ioannis Famelis ◽  
Peter C Chu ◽  
George Galanis
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Prediction Model ◽  
Simulation Model ◽  
Three Dimensional ◽  
Simulation System ◽  
High Order ◽  
Alternative Methodology ◽  
Runge Kutta ◽  
Fifth Order

The aim of this paper is to present an application of high-order numerical analysis methods to a simulation system that models the movement of a cylindrical-shaped object (mine, projectile, etc.) in a marine environment and in general in fluids with important applications in Naval operations. More specifically, an alternative methodology is proposed for the dynamics of the Navy’s three-dimensional mine impact burial prediction model, Impact35/vortex, based on the Dormand–Prince Runge–Kutta fifth-order and the singly diagonally implicit Runge–Kutta fifth-order methods. The main aim is to improve the time efficiency of the system, while keeping the deviation levels of the final results, derived from the standard and the proposed methodology, low.

THE RESOLUTION CORRECTION IN THE SCINTILLATION SPECTROMETRY OF CONTINUOUS X RAYS

1958 ◽  
Vol 36 (12) ◽  
pp. 1624-1633 ◽  
Author(s):  
W. R. Dixon ◽  
J. H. Aitken
Keyword(s):  
Integral Equation ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Analytical Procedure ◽  
Pulse Height ◽  
Matrix Inversion ◽  
Height Distribution ◽  
X Rays ◽  
Smooth Solutions ◽  
Pulse Height Distribution

The problem of making resolution corrections in the scintillation spectrometry of continuous X rays is discussed. Analytical solutions are given to the integral equation which describes the effect of the statistical spread in pulse height. The practical necessity of making some kind of numerical analysis is pointed out. Difficulties with numerical methods arise from the fact that the observed pulse-height distribution cannot be defined precisely. As a result it is possible in practice only to find smooth "solutions". Additional difficulties arise if the numerical method is based on an invalid analytical procedure. For example matrix inversion is of doubtful value in making the resolution correction because there does not appear to be an inverse kernel for the integral equation in question.

Numerical Analysis of Air Measuring Station Location Optimization in Underground Mine Airway

2014 ◽  
Vol 960-961 ◽  
pp. 621-624
Author(s):  
Jing Zhao Zhang ◽  
Yong Sheng Yan ◽  
Zhen Guo Yan ◽  
Feng Liang Wu
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Underground Mine ◽  
Inlet Velocity ◽  
Location Optimization ◽  
Measuring Station ◽  
Numerical Tests ◽  
Station Location

The optimized air measuring station location of mine airway based on air fully developed was proposed and numerical tests were conducted with six models. The independence of air fully development and inlet velocity was analyzed which validated the models and the numerical methods. The results show that optimized air measuring station location in head entry is 132m-198m after the airway turning while 5.0m-10.1m before the airway turning in tail entry.

scholarly journals An Anatomical Study of Scilla (Scilloideae) Section Chionodoxa and Scilla bifolia in Turkey1

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
H. YILDIRIM ◽  
K. YETISEN ◽  
A. ÖZDEMIR ◽  
C. ÖZDEMIR
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Analysis Of Variance ◽  
Leaf Anatomy ◽  
Pearson Correlation ◽  
Anatomical Study ◽  
Anatomical Variations ◽  
Vascular Bundles ◽  
Single Row ◽  
Scilla Bifolia

ABSTRACT In the present study Scilla luciliae, S. forbesii, S. sardensis, S. siehei, Scilla x allenii and S. bifolia are compared anatomically. Some differences have been found in root, scape, and leaf anatomy of the taxa, and commented. S. luciliae, S. forbesii, S. sardensis and S. siehei have a metaxylem at the center of the root, others have 3-4 number metaxylem. Vascular bundles in two row in S. luciliae and S. forbesii in a single row in S. sardensis, Scilla x allenii and S. bifolia though in three rows in S. siehei. Aerenchyma tissue is present in mesophyll of five taxa leaf except S. sardensis. The anatomical variations in the taxa have been investigated by means of numerical methods (Analysis of variance and Pearson correlation). By the analysis of the investigated taxa from 12 anatomy related characters, it has been also found that the results from numerical analysis of anatomy characters can provide additional evidences, which correspond to the anatomy for the recognition of the taxa.

scholarly journals Numerical analysis of axial fan characteristics

Mechanik ◽  
2018 ◽  
Vol 91 (7) ◽  
pp. 606-608
Author(s):  
Stanisław Wrzesień ◽  
Michał Frant ◽  
Maciej Majcher
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Flow Rate ◽  
Total Pressure ◽  
Volumetric Flow Rate ◽  
Total Efficiency ◽  
Axial Fan ◽  
Axial Fans ◽  
Basic Characteristics

The paper presents an analysis and comparison of basic characteristics of axial fans, both analytically and numerically. Such characteristics are: the characteristics of the total pressure, power and total efficiency as a function of the volumetric flow rate. The presented results showed significant quantitative and qualitative differences in the characteristics obtained by two methods. The usefulness of numerical methods in relation to the results of the initial analytical project was confirmed.

An Investigation of Cavitation and Suction Vortices Behavior in Pump Sump

2011 ◽  
Author(s):  
Won-Tae Kang ◽  
Ki Han Yu ◽  
Seung Yeob Lee ◽  
Byeong Rog Shin
Keyword(s):  
Experimental Investigation ◽  
Numerical Analysis ◽  
Test Procedure ◽  
Three Dimensional ◽  
Water Levels ◽  
National Standard ◽  
Piping System ◽  
Test Model ◽  
Grid Systems ◽  
Volume Method

A numerical and an experimental investigation on a suction vortices including cavitation, free vortices and subsurface vortices behavior in the model sump system with multi-intakes is performed at several flow rates and water levels. A test model sump and piping system were designed based on Froude similitude for the prototype of the recommended structure layout by HI-9.8 American National Standard for Pump Intake Design of the Hydraulic Institute. An experiment is performed according to the sump model test procedure of Hyosung Goodsprings, Inc. A numerical analysis of three dimensional multiphase flows through the model sump is performed by using the finite volume method of the CFX code with multi-block structured grid systems. A k-ω Shear Stress Transport turbulence model and the Rayleigh-Plesset cavitation model are used for solving turbulence cavitating flow. Several types of free surface and submerged vortex which occurs with each different water level are identified through the experimental investigation. From the numerical analysis, the vortices are reproduced and their formation, growing, shedding and detailed vortex structures are investigated. To reduce abnormal vortices, an anti-vortex device is considered and its effect is investigated and discussed.

Numerical analysis of air dissociation influence on spaceplane aerodynamic characteristics

2018 ◽  
Vol 148 ◽  
pp. 153-162 ◽  
Author(s):  
Nikolay A. Elisov ◽  
Sergey A. Ishkov ◽  
Valentin G. Shakhov
Keyword(s):  
Numerical Analysis ◽  
Aerodynamic Characteristics

A Simplified Numerical Analysis

1959 ◽  
Vol 63 (577) ◽  
pp. 59-62
Author(s):  
C. E. Maley
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods

Liaison between the engineering and computing sections of an aircraft company suffers when the engineer feels he is “losing control” of his own problems. This situation is typically due, not to distrust of the calculating engine, but to variance in the numerical methods favoured by the engineer and the engine programmer.

Application of harmonic balance method to aerodynamic characteristics prediction of spinning vehicle

2017 ◽  
Vol 89 (2) ◽  
pp. 347-357
Author(s):  
Tianyu Lu ◽  
Juanmian Lei ◽  
Xiaosheng Wu ◽  
Jintao Yin
Keyword(s):  
Computational Efficiency ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Aerodynamic Characteristics ◽  
Balance Method ◽  
Windward Side ◽  
Leeward Side ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Side Flow

Purpose The purpose of this paper is to examine the ability of the harmonic balance method for predicting the aerodynamic characteristics of rigid finned spinning vehicle. Design/methodology/approach The aerodynamic characteristics of a rigid four-finned spinning vehicle at Mach number 2.5 and angle of attack of 20 degrees are simulated using the harmonic balance method and the unsteady time-accurate approach based on the dual-time method. The numerical results are analyzed, and the computed aerodynamic coefficients of the harmonic balance method are compared with those of the dual-time method. The influence of the number of harmonics is presented. The computed Magnus force and moment coefficients are compared with the experimental data. The flow fields at different roll angles are presented. The computational efficiency of harmonic balance method is analyzed. Findings The results show that the aerodynamic coefficients of spinning vehicle could be predicted by the harmonic balance method with reasonable accuracy compared with the dual-time method. For the harmonic balance method, the accuracy of the computed leeward side flow is relatively poor compared with that of the computed windward side flow. Meanwhile, the computational efficiency is influenced by initial guess and the intensity of unsteady effect. Practical implications The harmonic balance method could be used for the aerodynamic prediction of spinning vehicle, which may improve the efficiency of vehicle design. Originality/value This paper presents the results of the harmonic balance method for simulating the aerodynamic characteristics of finned spinning vehicle. The accuracy and efficiency of the method are analyzed.

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