Inviscid gas flow in a nozzle with a bend in the contour ahead of the throat

1995 ◽  
Vol 30 (1) ◽  
pp. 107-111
Author(s):  
S. V. Yagudin
Keyword(s):  
Gas Flow ◽  
Inviscid Gas

The Size of Aerofoil Models for Quantitative Hydraulic Analogy Research

1956 ◽  
Vol 60 (543) ◽  
pp. 208-209
Author(s):  
R. A. A. Bryant
Keyword(s):  
Water Flow ◽  
Gas Dynamics ◽  
Recent Article ◽  
Gas Flow ◽  
Three Dimensional ◽  
Quantitative Investigation ◽  
Inviscid Gas ◽  
Small Incidence ◽  
Hydraulic Analogy ◽  
Physical Analogy

In a recent article Lundberg has made reference to use of the “ Hydraulic Analogy ” for quantitative investigation of gas dynamics phenomena. This is quite feasible provided that the basic analogy and its limitations are properly understood. In fact, considerable progress has already been made and it has been proved possible to utilise the analogy for both supersonic and transonic research.A study of the mathematical analogy indicates that the strongest physical analogy between a two-dimensional (inviscid) gas flow and a three-dimensional (viscous) water flow exists for the transonic case when the water depth is approximately one quarter inch and the model is towed. Only thin profiles with small incidence can be sensibly investigated. Under such conditions the analogous water flow may be considered as a distorted dissimilar model of a corresponding prototype gas flow.

scholarly journals Mathematical modeling of spatial gas flow in nozzles of nontrivial geometry

2021 ◽  
Vol 2094 (4) ◽  
pp. 042002
Author(s):  
S A Bitkin ◽  
M A Korepanov ◽  
M R Koroleva ◽  
A I Karpov ◽  
S S Makarov
Keyword(s):  
Gas Flow ◽  
Three Dimensional ◽  
Critical Section ◽  
Nozzle Geometry ◽  
Outlet Section ◽  
Flow Area ◽  
Flow Parameters ◽  
Inviscid Gas ◽  
Three Dimensional Models ◽  
The Mathematical Model

Abstract Numerical modeling of the spatial gas flow in an adjustable nozzle with an asymmetric critical section caused by the overlap of a part of the flow area by a gas flow regulator has been carried out. The mathematical model is based on three-dimensional models of gas dynamics, the method of large particles is used for calculation. When describing the unsteady flow of an inviscid gas, the system of Euler equations is used, written for a computational rectangular plane, taking into account the function of nozzle geometry. The results of calculations of flow parameters along a nozzle path with a uniform outlet section and with an obliquely cut outlet nozzle are presented. Calculations were carried out for completely open critical sections and for half overlapped. For oblique cut nozzles, the overlap of the critical section from the side of the short part and from the side of the long part of the oblique nozzle is considered.

Interactions of Space Bodies With Atmospheres of Planets

1997 ◽  
Vol 50 (11) ◽  
pp. 671-688 ◽  
Author(s):  
V. P. Stulov
Keyword(s):  
Numerical Methods ◽  
High Speed ◽  
Gas Flow ◽  
Space Vehicle ◽  
Body Motion ◽  
Modern Theory ◽  
Inviscid Gas ◽  
Meteor Body ◽  
Vehicle Aerodynamics ◽  
The Difference

In this review article, a modern theory of meteor body motion in the atmosphere is described. The theory is based on the results of high-speed aerodynamics. The author understands that such an application is difficult and unusual. The difference between space vehicle aerodynamics and bolide physics is, first of all, in absence of knowledge about shapes of meteoroids and of their physical-mechanical properties. On the other hand, the main aerodynamical laws are the same for vehicles and meteoroids. This permits one to achieve some new developments in meteor physics. In the first section, a simple analytical model for meteor trajectories is developed. The second and fourth sections of the article contain high-speed aerodynamics results: inviscid gas flow past bodies, and convective and radiative heat transfer. The third section is devoted to one of the difficult problems in meteor physics-the theory of meteoroid destruction due to aerodynamical loading. Finally, the fifth section contains some common questions on bolide phenomema. For the solution of meteor physics problems, both analytical and numerical methods are used. As such problems contain a number of determining parameters which are not accurately known, the analytical methods are preferable. The numerical methods are necessary for calculation of complex gasdynamical structures forming during the motion of the meteor bodies in the atmosphere. There are 50 references included at the end of this article.

Separated inviscid gas flow past a disk and a body with maximum critical Mach numbers

1996 ◽  
Vol 31 (3) ◽  
pp. 477-482
Author(s):  
L. M. Zigangareeva ◽  
O. M. Kiselev
Keyword(s):  
Gas Flow ◽  
Flow Past ◽  
Inviscid Gas ◽  
Mach Numbers

scholarly journals Numerical study of the aerodynamic characteristics of an axisymmetric profile of an optimized shape

2021 ◽  
pp. 5-11
Keyword(s):  
Gas Flow ◽  
Aerodynamic Drag ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Inviscid Gas ◽  
Speed Up ◽  
The Cost ◽  
Different Characteristics

Today, one of the important and urgent tasks of the aerodynamics science is the study and op-timization of aerodynamic characteristics of optimized profile shapes in a gas flow. This problem arises in the design of aircraft and various vessels and is associated with a rational choice of profile shape for a large number of different characteristics and, in particular, in terms of aerodynamic drag. In this paper, consider methods for optimizing an axisymmetric aerodynamic profile in a sta-tionary laminar inviscid gas flow at different angles of attack. The proposed method of solv-ing such a problem of optimization and numerical study of aerodynamic characteristics of the described body in the flow is relevant due to the complexity of its solution, for example, by traditional methods based on the Navier-Stokes system of differential equations. Experi-mental methods are based on expensive and time-consuming tools that do not guarantee find-ing the optimum. Such a computing tool as Ansys Fluent is well suited for solving such prob-lems of hydroaerodynamics and allows not only to speed up and reduce the cost of the compu-tational experiment, but also to increase the efficiency of its implementation. The article describes the process of finding the optimum, which reduces to minimizing the drag force of the previously described axisymmetric profile. A description is also given of the wing

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

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