scholarly journals Experimental and numerical investigations on the shape and roughness of cylindrical critical flow venturi nozzles (CFVN)

2019 ◽  
Author(s):  
Marc Antoine Lambert ◽  
Rémy Maury ◽  
Jean-Christophe Valière ◽  
Eric Foucault ◽  
Guillaume Lehnasch
Keyword(s):  
Numerical Experiments ◽  
Smooth Surface ◽  
Discharge Coefficient ◽  
Roughness Coefficient ◽  
Number Range ◽  
Numerical Investigations ◽  
Current State ◽  
High Reynolds ◽  
The Impact

This paper describes a part of a research project aimed at reducing the uncertainty of the determination of the CFVN discharge coefficient. In the current state of the work, there are two parallel studies: an experimental and a numerical. Experiments have been carried out to determine the impact of roughness on the CD and to demonstrate the need for dimension parameters, such as diameter and roughness coefficient characterisation. Numerical simulations are used in the same CFVN geometry with a smooth surface to determine the main parameters which can influence the numerical prediction of the discharge coefficient and the flow behaviour. The results show that an increase of roughness may lead to a significant decrease of the discharge coefficient, particularly in the high Reynolds number range.

Experimental Results of Flow Nozzle Based on PTC 6 for High Reynolds Number

2014 ◽  
Author(s):  
Noriyuki Furuichi ◽  
Kar-Hooi Cheong ◽  
Yoshiya Terao ◽  
Shinichi Nakao ◽  
Keiji Fujita ◽  
...  
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Discharge Coefficient ◽  
Experimental Results ◽  
Flow Conditions ◽  
Number Range ◽  
Discharge Coefficients ◽  
Reynolds Number Range ◽  
Lower Reynolds Number ◽  
High Reynolds

Discharge coefficients for three flow nozzles based on ASME PTC 6 are measured under many flow conditions at AIST, NMIJ and PTB. The uncertainty of the measurements is from 0.04% to 0.1% and the Reynolds number range is from 1.3×105 to 1.4×107. The discharge coefficients obtained by these experiments is not exactly consistent to one given by PTC 6 for all examined Reynolds number range. The discharge coefficient is influenced by the size of tap diameter even if at the lower Reynolds number region. Experimental results for the tap of 5 mm and 6 mm diameter do not satisfy the requirements based on the validation procedures and the criteria given by PTC 6. The limit of the size of tap diameter determined in PTC 6 is inconsistent with the validation check procedures of the calibration result. An enhanced methodology including the term of the tap diameter is recommended. Otherwise, it is recommended that the calibration test should be performed at as high Reynolds number as possible and the size of tap diameter is desirable to be as small as possible to obtain the discharge coefficient with high accuracy.

Further Investigation of Discharge Coefficient for PTC 6 Flow Nozzle in High Reynolds Number

2015 ◽  
Author(s):  
Noriyuki Furuichi ◽  
Yoshiya Terao ◽  
Shinichi Nakao ◽  
Keiji Fujita ◽  
Kazuo Shibuya
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
High Reynolds Number ◽  
Discharge Coefficient ◽  
Flow Region ◽  
Number Range ◽  
Discharge Coefficients ◽  
Reynolds Number Range ◽  
High Reynolds

The discharge coefficients of the throat tap flow nozzle based on ASME PTC 6 are measured in wide Reynolds number range from Red=5.8×104 to Red=1.4×107. The nominal discharge coefficient (the discharge coefficient without tap) is determined from the discharge coefficients measured for different tap diameters. The tap effects are correctly obtained by subtracting the nominal discharge coefficient from the discharge coefficient measured. Finally, by combing the nominal discharge coefficient and the tap effect determined in three flow regions, that is, laminar, transitional and turbulent flow region, the new equations of the discharge coefficient are proposed in three flow regions.

The change of maximum surface runoff characteristics and following risks for the settlements infrastructure (on the example of the biathlon complex construction in Yuzhno-Sakhalinsk)

2019 ◽  
Vol 13 (1) ◽  
pp. 56-67
Author(s):  
M. R. Kuznetsova ◽  
A. A. Pashovkina ◽  
Yu. V. Gensiorovskiy
Keyword(s):  
Surface Runoff ◽  
Field Work ◽  
Maximum Surface ◽  
Erosion Processes ◽  
Current State ◽  
Analytical Formulas ◽  
Maximum Water ◽  
The Impact ◽  
Rain Floods

The determination of maximum water discharges of floods and rain floods at small mountain streams is relevant for engineering and construction purposes. However, currently, the accounting of the surface runoff of small watercourses is often neglected when construction works are being carrying out. This fact leads to various problems with the exploitation of constructed objects. The purpose of this work is to assess the impact of the construction of the biathlon complex in the recreational area of Yuzhno-Sakhalinsk on the maximum surface runoff from the territory that it occupies. Maps of natural and anthropogenically transformed catchments of the territory were created with the usage of the data, collected during the field work in the summer of 2018. Hydrographical characteristics of both kinds of catchments were determined in accordance with generally accepted recommendations. On the basis of the obtained data, there was carried out the comparative analysis of the current state of the study area and its characteristics before the creation of sports facilities in years 2016–2017. The calculations of the maximum runoff in periods of flood and rain floods according to analytical formulas recommended in the literature were made. The results of the calculations clearly show that water discharges from this area during the period of flood and rain floods increased after the construction of the complex in comparison with discharges observed before construction. Studies have confirmed that the construction of biathlon tracks on the mountainside led to the increase in surface runoff from this area, which is the reason for the overflow of the urban storm sewer of Yuzhno-Sakhalinsk during the period of flood and rain floods, stormwater outlets on the day surface and the activation of erosion processes, suffusion on the considered territory.

Development of High Accurate Flow Nozzle for Feedwater Flowrate Measurement in Nuclear Power Plant

2014 ◽  
Author(s):  
Noriyuki Furuichi ◽  
KarHooi Cheong ◽  
Yoshiya Terao ◽  
Shinichi Nakao ◽  
Keiji Fujita ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Nuclear Power ◽  
Discharge Coefficient ◽  
Reynolds Numbers ◽  
Experimental Results ◽  
Number Range ◽  
Discharge Coefficients ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Extrapolation Error

The high accurate throat tap flow nozzle with four different diameter taps is developed and its discharge coefficients are measured in the Reynolds number range from 1.5×106 to 1.4×107 using the high Reynolds calibration facility of AIST,NMIJ. The discharge coefficient of a throat tap nozzle extrapolated according to ASME PTC 6 are confirmed to deviate 0.37% at Red=1.4×107 from the experimental results. The high accurate flow nozzle developed can reduce this extrapolation error of the discharge coefficient to high Reynolds numbers by using the equations of discharge coefficients, which is determined as a function of Reynolds number and tap diameter based on the experimental results of four different diameter taps. The error of extrapolated discharge coefficient using the derived equations is estimated to be less than 0.1% at Red=1.4×107. The present results show that the throat tap flow nozzle developed is expected to work as a high accurate flowmeter even under the extrapolation of the discharge coefficient toward high Reynolds numbers.

scholarly journals Morphological and Morphometrical Analyses Reveal the Avalanche Influence over the Talus Cones in the Rybi Potok Valley, Tatra Mountains

2015 ◽  
Vol 49 (1) ◽  
Author(s):  
Michał Lempa ◽  
Ryszard J. Kaczka ◽  
Zofia Rączkowska
Keyword(s):  
Morphometric Parameters ◽  
Roughness Coefficient ◽  
Tatra Mountains ◽  
Research Knowledge ◽  
Physical Weathering ◽  
Topographic Position Index ◽  
Maximal Height ◽  
Position Index ◽  
The Impact

AbstractIntense physical weathering engenders formation of scree cones at the foot of slopes dissected by couloirs. Combination of several geomorphic processes operating within the slope results in formation of cones of a polygenetic character (talus-alluvial cones, rockfall talus cones, or – in particular cases, talus-alluvial-avalanche cones). This study was aimed at determination of morphometric parameters characteristic for particular morphogenetic types of the cones in the Rybi Potok Valley in the High Tatra Mountains. For the purpose of the research, knowledge about the terrain and available cartographic materials (geological, geomorphological and topographical maps, LiDAR data) were employed. In the studied valley, 24 cones were selected and for each of them, morphogenetic types and morphometric parameters (surface, minimal and maximal height, roughness coefficient, Topographic Position Index) were determined. The correlations between different parameters enabled establishment and determination of the combination of morphometric parameters typical for the particular types of the cones. The impact of snow avalanches on one of the cones (at the mouth of Żleb Żandarmerii) was identified. This cone has morphometric parameters dissimilar to those of the other cones in the studied valley. It is the only cone in the valley which was classified as the avalanche cone.

scholarly journals THE DEVELOPMENT OF SOCIAL ENTREPRENEURSHIP IN THE KHANTY-MANSI AUTONOMOUS DISTRICT - YUGRA

2017 ◽  
Vol 13 (4) ◽  
pp. 27-33
Author(s):  
Lioubov Leonidovna Bogomolova
Keyword(s):  
Social Entrepreneurship ◽  
Practical Importance ◽  
State Support ◽  
Current State ◽  
Expert Assessments ◽  
Social Initiatives ◽  
The Impact ◽  
Further Development

In the article the tendencies of development of social entrepreneurship at the present stage are considered, and the state support of this sphere of entrepreneurship is estimated. The main directions of state support of social entrepreneurship of Ugra are marked and priorities and key tasks are outlined. The urgency of the work lies in the increasing role of the development of social initiatives in entrepreneurship and state support for social entrepreneurship as a phenomenon in public life. The aim of the research, the results of which are given in this article, is to assess the role of state support in the development of social entrepreneurship in Yugra. The scientific significance of the research is a comprehensive study of the impact of state support on the current state of social entrepreneurship and the development of social initiatives. The practical importance of the work lies in applying the results of research in decision-making in the field of social project management and their effectiveness in implementation. The objectives of the study are: determination of directions of state support affecting the development of social entrepreneurship; determining the degree of influence of state support on the development of social entrepreneurship in the Autonomous Okrug; forecasting the further development of social entrepreneurship. In the process of scientific research, logical and formal methods of analysis and statistics were used: comparisons, computational and constructive, graphical, expert assessments, and others. The result of this work is the identification of the factors influencing state support for the development of social entrepreneurship in Ugra.

scholarly journals The formation of worldview of the doctors of traditional medicine in China, Mongolia, and Russia

2020 ◽  
pp. 79-87
Author(s):  
Subad Bal'zhinimaevna Dashieva ◽  
Oyuuna Sanzhimitupovna Rinchinova ◽  
Nomin' Dondokovna Tsyrenova
Keyword(s):  
Traditional Medicine ◽  
Religious Beliefs ◽  
Buddhist Philosophy ◽  
Tibetan Medicine ◽  
Special Contribution ◽  
Current State ◽  
Traditional Tibetan Medicine ◽  
The Impact

The subject of this research is the current state of the system of traditional medical system in China, Mongolia and Russia. The object of this research is the role of a doctor in development of the traditional medicine (Tibetan) in China, Mongolia and Russia. The authors conduct comparative analysis between the degree of integratedness of the doctor of traditional medicine into the general medical and scientific-educational environment of one or another country, and degree of their demand in practical health care. Special attention is given to the sources of biographical records on the doctors of Tibetan medicine in Old Mongolian and Chinese languages, as well as to the problem of the impact of sociocultural and normative legal environment upon personal becoming of the doctor of traditional medicine. The main conclusions consist in determination of commonality of religious beliefs and the method of acquisition of knowledge on Tibetan medicine in the context of Buddhist philosophy, as well as the fact that traditional Tibetan medicine is interrelated with Buddhism, in which the system of the so-called “direct transfer” of knowledge from the teacher to a student has sacred and fundamental meaning in becoming of the healer monk. The authors' special contribution to the research is defined by introduction into the scientific discourse of previously unpublished records on the doctors of Tibetan medicine in China, Mongolia and Russia. The novelty consists in conducting the analysis of factors that unite the doctors of Tibetan medicine in China, Mongolia and Russia, as well as in reveling the commonality of religious beliefs and method of acquisition of knowledge of Tibetan medicine in the context of Buddhist philosophy.

Vortex Shedding and Acoustic Resonance of Single and Tandem Finned Cylinders

2010 ◽  
Author(s):  
Mohammed Eid ◽  
Samir Ziada
Keyword(s):  
Vortex Shedding ◽  
Sound Pressure ◽  
Interaction Mechanism ◽  
Cross Flow ◽  
Acoustic Resonance ◽  
Number Range ◽  
Tandem Cylinders ◽  
Spacing Ratio ◽  
High Reynolds ◽  
The Impact

The effect of fins on vortex shedding and acoustic resonance is investigated for isolated and two tandem cylinders exposed to cross-flow in a rectangular duct. Three spacing ratios between the tandem cylinders (S/De = 1.5, 2 and 3) are tested for a Reynolds number range from 1.6×104 to 1.1×105. Measurements of sound pressure and flow velocity are performed for bare and finned cylinders with three different fin densities. The effect of fins on the sound pressure generated before the onset of acoustic resonance as well as during the pre-coincidence and coincidence resonance is found to be rather complex and depends on the spacing ratio between cylinders, the fin density and the nature of the flow-sound interaction mechanism. For isolated cylinders, the fins reduce the strength of vortex shedding only slightly, but strongly attenuate the radiated sound before and during the acoustic resonance. This suggests that the impact of the fins on correlation length is stronger than on velocity fluctuations. In contrast to isolated cylinders, the fins in the tandem cylinder case enhance the vortex shedding process at off-resonant conditions, except for the large spacing case which exhibits a reversed effect at high Reynolds numbers. Regarding the acoustic resonance of the tandem cylinders, the fins promote the onset of the coincidence resonance, but increasing the fin density drastically weakens the intensity of this resonance. The fins are also found to suppress the pre-coincidence resonance for the tandem cylinders with small spacing ratios (S/De = 1.5 and 2), but for the largest spacing case (S/De = 3), they are found to have minor effects on the sound pressure and the lock-in range.

Review of the Current State and Future Development in Standardizing Natural Lighting in Interiors

2018 ◽  
pp. 5-26 ◽  
Author(s):  
Stanislav Darula
Keyword(s):  
Human Life ◽  
Natural Light ◽  
Artificial Lighting ◽  
Computer Tools ◽  
Natural Lighting ◽  
Current State ◽  
Minimum Requirements ◽  
Life On Earth ◽  
Window Design

Three elements mainly wind, water and sun seemed to determine in ancient ages the basic phenomena of life on Earth. Architectural history documented the importance of sun influence on urban and building construction already in layouts of Mesopotamian and Greek houses. Not only sun radiation but especially daylight played a significant role in the creation of indoor environment. Later, in the 20th century, a search of interaction between human life in buildings and natural conditions were studied considering well­being and energy conscious design recently using computer tools in complex research and more detail interdisciplinary solutions. At the same time the restricted daytime availability of natural light was supplemented by more efficient and continually cheaper artificial lighting of interiors. There are two main approaches to standardize the design and evaluation of indoor visual environment. The first is based on the determination of the minimum requirements respecting human health and visibility needs in all activities while the second emphasizes the behaviour and comfort of occupants in buildings considering year­around natural changes of physical quantities like light, temperature, noise and energy consumption. The new current standardization basis for daylight evaluation and window design criteria stimulate the study of methodology principles that historically were based on the overcast type of sky luminance pattern avoiding yearly availability of sky illuminance levels. New trends to base the daylight standardization on yearly or long­term availability of daylight are using the averages or median sky illuminance levels to characterise local climatological conditions. This paper offers the review and discussion about the principles of the natural light standardization with a short introduction to the history and current state, with a trial to focus on the possible development of lighting engineering and its standards in future.

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