Work in Progress in France Related to Computation of Profiles for Turbomachine Blades by Hodograph Method

1972 ◽  
Author(s):  
R. G. Legendre
Keyword(s):  
Ideal Fluid ◽  
Industrial Development ◽  
Critical Value ◽  
Hodograph Method ◽  
Subsonic Flows ◽  
Transonic Flows ◽  
The Real ◽  
Work In Progress ◽  
Real Fluid ◽  
Turbomachine Blade

The hodograph method has been used extensively in France for the computation of turbomachine blade profiles. The work started in 1939 but the industrial development took place during the last decades. This paper presents recent research and the results obtained. The method used in “Association Technique pour la Turbine à Gaz” (ATTAG) and in industry concerns the assimilation of the real fluid to the Chapligin ideal fluid. It permits only calculation of profiles for subsonic flows but provides quite satisfactory predictions for velocities near the critical value. It is easy to use. More complicated developments are undertaken for defining profiles adapted to reversible transonic flows, i.e., without shock. Different methods providing similar results are being studied by several groups in ONERA.

Analysis of the Real Area of Contact Between a Polymeric Magnetic Medium and a Rigid Surface

1984 ◽  
Vol 106 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Complex Modulus ◽  
Critical Value ◽  
Computer Applications ◽  
Hard Material ◽  
Rigid Surface ◽  
Magnetic Medium ◽  
The Real ◽  
Real Area Of Contact ◽  
The Mean ◽  
Real Area

The statistical analysis of the real area of contact proposed by Greenwood and Williamson is revisited. General and simplified equations for the mean asperity real area of contact, number of contacts, total real area of contact, and mean real pressure as a function of apparent pressure for the case of elastic junctions are presented. The critical value of the mean asperity pressure at which plastic flow starts when a polymer contacts a hard material is derived. Based on this, conditions of elastic and plastic junctions for polymers are defined by a “polymer” plasticity index, Ψp which depends on the complex modulus, Poisson’s ratio, yield strength, and surface topography. Calculations show that most dynamic contacts that occur in a computer-magnetic tape are elastic, and the predictions are supported by experimental evidence. Tape wear in computer applications is small and decreases Ψp by less than 10 percent. The theory presented here can also be applied to rigid and floppy disks.

The Instability of a Flexible Sheet in Uniform Parallel Flow

2007 ◽  
Author(s):  
Michael T. Morris-Thomas ◽  
Sverre Steen
Keyword(s):  
Spectral Method ◽  
Ideal Fluid ◽  
Flow Instability ◽  
Fluid Dynamic ◽  
Fluid Velocity ◽  
Critical Value ◽  
Elastic Model ◽  
Elastic Instability ◽  
Mass Ratio ◽  
Unique Aspect

When a flexible sheet immersed in a fluid is under the influence of uniform flow, instability can arise when the fluid velocity reaches some critical value. The fluid-elastic instability known as flutter is the focus of this present work. We present a fluid-elastic model for a flexible sheet whereby the fluid dynamic lift is accounted for by the classical slender body approximation of Lighthill [1] for an ideal fluid. We describe aspects of the system in terms of a mass ratio α and a tension to flexural ratio γ. The model is solved by a spectral method to determine the fluid velocity and frequency at which instability occurs. In addition, we consider the fluid friction and damping on the response of the flexible sheet. Moreover, we compare predictions for the flutter velocity and frequency with published results. The unique aspect of this work is an investigation into the effect of additional tension, in the form of the ratio γ, on stability.

scholarly journals A note on the flow induced by a line sink beneath a free surface

1991 ◽  
Vol 32 (3) ◽  
pp. 251-260 ◽  
Author(s):  
G. C. Hocking ◽  
L. K. Forbes
Keyword(s):  
Free Surface ◽  
Froude Number ◽  
Stagnation Point ◽  
Ideal Fluid ◽  
Critical Value ◽  
Homogeneous Fluid ◽  
Substitution Method ◽  
A Value ◽  
Line Sink ◽  
Low Froude Number

AbstractThe problem of withdrawing water through a line sink from a region containing an homogeneous fluid beneath a free surface is considered. Assuming steady, irrotational flow of an ideal fluid, solutions with low Froude number containing a stagnation point on the free surface above the sink are sought using a series substitution method. The solutions are shown to exist for a value of the Froude number up to a critical value of about 1.4. No solutions of this type are found for Froude numbers greater than this value.

The real world transmission loss chamber: A work in progress

2013 ◽  
Vol 134 (5) ◽  
pp. 4093-4093
Author(s):  
Jay Bliefnick ◽  
Andrew M. Hulva ◽  
Dominique J. Chéenne
Keyword(s):  
Real World ◽  
Transmission Loss ◽  
The Real ◽  
Work In Progress

Financialisation and development: a case study of Ethiopia

2019 ◽  
Vol 11 (2) ◽  
pp. 138-196
Author(s):  
Anne Löscher
Keyword(s):  
Real Estate ◽  
Financial Development ◽  
Industrial Development ◽  
Real Estate Market ◽  
Economic Research ◽  
Content Type ◽  
The Real ◽  
The Real Estate ◽  
The Real Estate Market ◽  
Debt Levels

Purpose This paper aims to shed light on financial development in Ethiopia and its implications for overall economic development. It does so with particular focus on development understood as industrial development and with special attention drawn on inequality and debt levels as well as the real estate market in Ethiopia. Two research questions are focussed on in particular, where the first serves as prerequisite for the assessment of the second: What kind of financial development took place in Ethiopia in the past quarter of a century? Furthermore, are processes of financialisation visible in Ethiopia, and if so, to what effect? Design/methodology/approach The paper is based on publicly available macro-data and qualitative and quantitative data collected by the author herself during a three months’ research stay in Ethiopia. Findings It is found that despite higher levels of financial inclusion and deepening, industrialisation is on a relative decline. What is more, inequality and debt levels increase, and the recent growth spurts seem to be rooted in the construction sector with prices in the real estate market surging. In can be concluded that despite a flourishing financial sector, the Ethiopian economy is faced with the peril of crises associated with an inflated real estate market, inequality, debt burdens and impeded industrialisation. Originality/value African economies and, in particular, the development and effects of financial markets are still a blind spot in economic research. By combining quantitative and qualitative data on and gathered in Ethiopia, this paper therefore conducts greenfield research.

The Increasing Role of the Real Sector in Building a Post-Industrial Economic System

2021 ◽  
Vol 26 (12) ◽  
pp. 1367-1371
Author(s):  
A. S. Shatrovskaya
Keyword(s):  
Economic System ◽  
Industrial Development ◽  
High Tech ◽  
Real Sector ◽  
The Real ◽  
Services Sector ◽  
National Economic ◽  
Post Industrial ◽  
Industrial Economic

Aim. The presented study aims to examine international experience and current domestic practices to develop scientifically grounded proposals for Russia’s transition towards a post-industrial economic system based on the integration between the real sector and the high-tech services sector in the context of globalization.Tasks. The authors analyze the classical foundations of the post-industrial economic system and develop a mechanism for its formation under modern conditions; determine the key characteristics of the real sector and characterize its relationship with the financial sector and the services sector in the process of building and developing a post-industrial economic system; identify the fundamental problems that hinder Russia’s transition towards a post-industrial economic system; identify the key elements of the modernization of the national economic policy aimed at strengthening innovation susceptibility and transparency, which is an essential prerequisite for the transition towards a postindustrial economic system; justify the need for the formation of a high-tech real sector and its integration with the high-tech services sector within the framework of a systemic production process.Methods. This study critically analyzes the classical concepts of a post-industrial economic system that determines the behavior of economic entities at various levels as well as existing views on the mechanism of its construction. Analytical tools are used to propose a modification of the fundamentals of the transition towards a post-industrial economic system in the context of global competition and economic instability. The related directions of changes in the national economic policy are substantiated and their target function is determined.Results. The study, which is aimed at building a post-industrial economic system, shows the increasing role of the high-tech real sector and its relationship with the high-tech services sector. This allowed the authors to justify the necessity of forming a single conceptual model of the systemic production process that would unite all high-tech sectors of the economy, with the predominant development of the real sector. The implementation of such a model will ensure Russia’s transition towards a post-industrial economic system, taking into account the opportunities and risks introduced by globalization.Conclusions. The prospects for the post-industrial development of the Russian economy and the regulatory role of the government as the manager of post-industrial development on the basis of the increasing role of the real sector are determined.

On the Hydrodynamic Analogy of Torsion

1935 ◽  
Vol 2 (2) ◽  
pp. A46-A48
Author(s):  
J. P. Den Hartog ◽  
J. G. McGivern
Keyword(s):  
Cross Sections ◽  
Ideal Fluid ◽  
Mathematical Identity ◽  
The Real ◽  
Hydrodynamic Analogy ◽  
The Ideal

Abstract The authors herein describe a means for carrying out experimentally Kelvin’s hydrodynamic analogy. A real liquid is used instead of the “ideal fluid” required by the analogy, the eddying flow caused thereby which violates the mathematical identity between the two cases being eliminated by taking photographs of the real liquid before eddying flow begins. The apparatus makes it possible to obtain photographs representing stress lines in shafts and also pictures of warped cross-sections.

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