scholarly journals EXPERIMENTAL DETERMINATION OF THE LEVEL OF INCIPIENT TURBULENCE IN THE WORKING PART OF THE T-1 WIND TUNNEL OF IVAN KOZHEDUB KHARKIV NATIONAL AIR FORCE UNIVERSITY

2021 ◽  
Vol 5 (2) ◽  
pp. 98-102
Author(s):  
Віталій Бездєльний ◽  
Сергій Шевченко ◽  
Ілля Грідасов
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Wind Tunnel ◽  
Experimental Determination ◽  
Air Force ◽  
Normal Condition ◽  
Aerodynamic Drag ◽  
Experimental Studies ◽  
The Subject

The subject of the article is to determine the level of incipient turbulence in the wind tunnel T-1 which is based on the method of measuring the pressure drop. The purpose is to experimentally determine the level of incipient turbulence in the working part of wind tunnel T-1 of Ivan Kozhedub Kharkiv National Air Force University in preparation for aerodynamic testing of aircraft models. Research methods: the method of pressure drop on the surface of the sphere by drainage. The following results of experimental determination of the level of incipient turbulence in the wind tunnel T-1 were obtained. It is established that the wind tunnel T-1 has a level of incipient turbulence 0,5…0,9 %, which corresponds to the normal condition for further experimental studies. Conclusions. According to the results of studies of the incipient turbulence in the wind tunnel T-1 by the method of pressure drop, the main dependences are obtained, and the incipient turbulence of the flow for the wooden sphere x = 0,9 %, and for the metal sphere x = 0,5 %, is determined. Determining the pressure distribution and aerodynamic drag does not involve measures to balance the aerodynamic scales and their certification, which determines the necessary role in the obtained reliable results of the experimental study, and this favors the drainage method.

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Experimental Studies of Force Systems on Steered Agricultural Tyres

1966 ◽  
Vol 181 (1) ◽  
pp. 133-148 ◽  
Author(s):  
P. A. Taylor ◽  
R. Birtwistle
Keyword(s):  
Experimental Determination ◽  
Experimental Studies ◽  
Soil Surface ◽  
Slip Angle ◽  
Vertical Load ◽  
Force Systems

The paper reports the experimental determination of the force systems acting on free-rolling 7–50 times 16 agricultural tyres, measured with a six-component suspension of the test wheel. Multivariate experimentation techniques were used involving five variables: slip angle, camber, vertical load, tyre pattern and land or furrow operation. The results are presented as three force and three moment components; other methods of representation are discussed briefly. Although the side or cornering force depends on many factors, particularly the soil surface, and is therefore difficult to predict, it is suggested that the draught force (i.e. resistance in the direction of motion) can be expressed as a function of slip for all surfaces.

Experimental Studies on Aerodynamic Characteristics of Pantograph System According to the Pantograph Cover Configurations for High Speed Train

2011 ◽  
Author(s):  
Yeongbin Lee ◽  
Minho Kwak ◽  
Kyu Hong Kim ◽  
Dong-Ho Lee
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Experimental Studies ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Experimental Models ◽  
High Speed Train ◽  
Drag And Lift

In this study, the aerodynamic characteristics of pantograph system according to the pantograph cover configurations for high speed train were investigated by wind tunnel test. Wind tunnel tests were conducted in the velocity range of 20∼70m/s with scaled experimental pantograph models. The experimental models were 1/4 scaled simplified pantograph system which consists of a double upper arm and a single lower arm with a square cylinder shaped panhead. The experimental model of the pantograph cover is also 1/4 scaled and were made as 4 different configurations. It is laid on the ground plate which modeled on the real roof shape of the Korean high speed train. Using a load cell, the aerodynamic force such as a lift and a drag which were acting on pantograph system were measured and the aerodynamic effects according to the various configurations of pantograph covers were investigated. In addition, the total pressure distributions of the wake regions behind the panhead of the pantograph system were measured to investigate the variations of flow pattern. From the experimental test results, we checked that the flow patterns and the aerodynamic characteristics around the pantograph systems are varied as the pantograph cover configurations. In addition, it is also found that pantograph cover induced to decrease the aerodynamic drag and lift forces. Finally, we proposed the aerodynamic improvement of pantograph cover and pantograph system for high speed train.

scholarly journals I. On the theory of lubrication and its application to Mr. Beauchamp tower’s experiments, including an experimental determination of the viscosity of olive oil

1886 ◽  
Vol 40 (242-245) ◽  
pp. 191-203 ◽  
Keyword(s):  
Olive Oil ◽  
Experimental Determination ◽  
Friction And Wear ◽  
Viscous Fluids ◽  
Solid Surfaces ◽  
Fundamental Importance ◽  
Theoretical Treatment ◽  
The Subject

Lubrication, or the action of oils and other viscous fluids to diminish friction and wear between solid surfaces, does not appear to have hitherto formed a subject for theoretical treatment. Such treatment may have been prevented by the obscurity of the physical actions involved, which belong to a class as yet but little known, namely, the boundary or surface actions of fluids; but the absence of such treatment has also been owing to the want of any general laws revealed by experiment. The subject is of such fundamental importance in practical mechanics, and the opportunities of observation so frequent, that it may well be a matter of surprise that any general laws should have for so long escaped detection.

IV. On the theory of lubrication and its application to Mr. Beauchamp tower’s experiments, including an experimental determination of the viscosity of olive oil

1886 ◽  
Vol 177 ◽  
pp. 157-234 ◽  
Keyword(s):  
Olive Oil ◽  
Experimental Determination ◽  
Friction And Wear ◽  
Viscous Fluids ◽  
Solid Surfaces ◽  
Fundamental Importance ◽  
Theoretical Treatment ◽  
The Subject

1. Lubrication, or the action of oils and other viscous fluids to diminish friction and wear between solid surfaces, does not appear to have hitherto formed a subject for theoretical treatment. Such treatment may have been prevented by the obscurity of the physical actions involved, which belong to a class as yet but little known, namely, the boundary or surface actions of fluids; but the absence of such treatment has also been owing to the want of any general laws discovered by experiment. The subject is of such fundamental importance in practical mechanics, and the opportunities for observation are so frequent, that it may well be a matter of surprise that any general laws should have for so long escaped detection.

scholarly journals Measurability of D-concurrence

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
N. Karimi ◽  
A. Heshmati ◽  
M. Yahyavi ◽  
M. A. Jafarizadeh ◽  
A. Mohammadzadeh
Keyword(s):  
Quantum Information ◽  
Experimental Determination ◽  
Pure State ◽  
Information Science ◽  
Direct Method ◽  
Entanglement Measure ◽  
Quantum Information Science ◽  
The Subject ◽  
A Direct Method

AbstractAn effective approach to quantify entanglement of any bipartite systems is D-concurrence, which is important in quantum information science. In this paper, we present a direct method for experimental determination of the D-concurrence of an arbitrary bipartite pure state. To do this, we show that measurement of the D-concurrence of bipartite pure state can be conversed into the measurement performed on some observables so called generalized Gell-Mann operators. We first introduce the concept of D-concurrence for a bipartite system. Then we explain the method of measuring this entanglement measure for the pure state. Finally, for clarify of the subject, we give an example consisting of two parties A and B with dimensions 3.

Experimental Determination of Oscillatory Lift and Moment Distributions on Fully Submerged Flexible Hydrofoils

1963 ◽  
Vol 7 (04) ◽  
pp. 24-41
Author(s):  
Guido E. Ransleben ◽  
H. Norman Abramson
Keyword(s):  
Steady State ◽  
Wind Tunnel ◽  
Aspect Ratio ◽  
Experimental Determination ◽  
Theoretical Predictions ◽  
Wind Tunnel Data

Measured span wise distributions of steady state and oscillatory lift and moment on fully submerged cantilever hydrofoils are presented. The hydrofoils were of aspect ratio 5 rectangular platform, and were towed at speeds sufficiently low to avoid cavitation. The data are compared with theoretical predictions and wind-tunnel data previously obtained at higher values of reduced velocity.

Experimental Determination of the Roller Chain Load Distribution

1983 ◽  
Vol 105 (3) ◽  
pp. 331-338 ◽  
Author(s):  
M. R. Naji ◽  
K. M. Marshek
Keyword(s):  
Experimental Study ◽  
Experimental Determination ◽  
Elastic Properties ◽  
Load Distribution ◽  
Noticeable Effect ◽  
Roller Chain ◽  
Chain Link ◽  
A Chain ◽  
Theoretical Results

An experimental study was conducted to determine the effect of elastic properties, geometric variations, and lubrication on roller chain load distribution. Comparison was made with the theoretical results for a test chain on a 20-tooth sprocket. The load distribution was found for a large number of cases to be independent of the elastic properties of the chain and the sprocket. The load distribution for the chain on a driver sprocket differed from that for a chain on a driven sprocket because of the change in direction of the friction force. Lubrication had no noticeable effect. A large pitch for the sprocket teeth was found to amplify the tension in the chain link.

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