scholarly journals The hydraulic resistance coefficient in the conditions of simultaneous effect of Re, Fr and Unknown node mfrac found in MathML fragment.$ {B \over h} $

2019 ◽  
Vol 97 ◽  
pp. 05031 ◽  
Author(s):  
George Volgin
Keyword(s):  
Hydraulic Resistance ◽  
Turbulent Flows ◽  
Functional Dependence ◽  
Fluid Motion ◽  
Integrated Approach ◽  
Resistance Coefficient ◽  
Hydraulic Structures ◽  
Turbulent Regime ◽  
Hydraulic Resistance Coefficient ◽  
The Impact

One of the most important tasks of engineering hydraulics is to determine the energy loss during the motion of the fluid flow. The study of the question of whether the patterns of hydraulic resistances are similar in a calm and turbulent flow is relevant in the design of hydraulic structures. In most cases, a turbulent regime of fluid motion is observed in various applications, but to date, the theory of turbulence is not considered complete. When designing hydraulic structures, inaccuracies in the existing calculation methods can lead to a decrease in the efficiency and reliability of the entire spillway structure as a whole. The need for an integrated approach to the analysis of the impact on the hydraulic resistance of various factors is noted (degree of spread $ \left( {{B \over h}} \right) $), the degree of turbulence (Re) and the degree of flow roughness (Fr)), which is not always provided by known dependencies and methods of calculation. On the basis of our own experimental data, a new formula for calculating the hydraulic resistance of turbulent flows in smooth channels was obtained. The functional dependence of the hydraulic resistance coefficient on the parameters $ \left( {{B \over h}} \right) $, Re and Fr is obtained.

scholarly journals The regularities of resistance and flow in pipes and wide channels

2018 ◽  
Vol 193 ◽  
pp. 02034
Author(s):  
Ilya Bryansky ◽  
Yuliya Bryanskaya ◽  
Аleksandra Оstyakova
Keyword(s):  
Comparative Analysis ◽  
Velocity Profile ◽  
Hydraulic Resistance ◽  
Cross Section ◽  
Resistance Coefficient ◽  
Hydraulic Structures ◽  
Hydraulic Characteristics ◽  
Hydraulic Resistance Coefficient ◽  
Logarithmic Velocity Profile

The data of hydraulic characteristics of flow are required to be more accurate to increase reliability and accident-free work of water conducting systems and hydraulic structures. One of the problems in hydraulic calculations is the determination of friction loss that is associated with the distribution of velocities over the cross section of the flow. The article presents a comparative analysis of the regularities of velocity distribution based on the logarithmic velocity profile and hydraulic resistance in pipes and open channels. It is revealed that the Karman parameter is associated with the second turbulence constant and depend on the hydraulic resistance coefficient. The research showed that the behavior of the second turbulence constant in the velocity profile is determined mainly by the Karman parameter. The attached illustrations picture the dependence of logarithmic velocity profile parameters based on different values of the hydraulic resistance coefficient. The results of the calculations were compared to the experimental-based Nikuradze formulas for smooth and rough pipes.

scholarly journals ANALYSIS OF THE RESULTS OF PERFORATED DRAINAGE PIPELINES CALCULATION IN THE PRESENCE OF TRANSIT FLOW RATE

2021 ◽  
pp. 42-46
Author(s):  
Andriy Kravchuk ◽  
Oleksandr Kravchuk
Keyword(s):  
Flow Rate ◽  
Final Section ◽  
Fluid Motion ◽  
Resistance Coefficient ◽  
Main Flow ◽  
Drain Water ◽  
Transit Flow ◽  
Simplified Method ◽  
Calculation Results ◽  
The Impact

A method of calculating the error that occurs when determining the flow rate in the final section of the pressure perforated drainage pipeline when it passes transit flow rate, based on the analysis of differential equations describing the fluid motion with variable flow rate in such pipelines is proposed in the paper. The analysis is presented in dimensionless form. The impact of transit flow on the main flow is estimated using the values ​​of the drainage pipeline resistance coefficient ζl and the generalized parameter of the perforated drain A, which takes into account its constructive and filtration characteristics. The obtained calculation formulas are quite simple and easy to use. The proposed method allows to perform calculations of drainage pipelines that operate in the presence of transit flow rate, according to the method of these pipes calculation that dispose drain water without passing transit. Herewith, the possible error, which includes in the calculation results, determines. To illustrate the obtained dependences, the corresponding graphs are given in the paper. The results of the analysis allow to determine the limits within which a simplified method of calculating these pipes can be used and the error, that occurs, can be estimated

scholarly journals Collecting of finely dispersed particles by means of a separator with the arc-shaped elements

2019 ◽  
Vol 126 ◽  
pp. 00007 ◽  
Author(s):  
Andrey V. Dmitriev ◽  
Vadim E. Zinurov ◽  
Oksana S. Dmitrieva
Keyword(s):  
Hydraulic Resistance ◽  
Flow Rate ◽  
Gas Flow ◽  
Reynolds Numbers ◽  
Resistance Coefficient ◽  
Dusty Gas ◽  
Gas Flow Rate ◽  
Hydraulic Resistance Coefficient ◽  
Purification Efficiency ◽  
Dispersed Particles

This paper includes the description of a separator, developed by the authors for the gas flow purification from the finely dispersed particles. The authors also studied the influence of the separator dimensions and the dusty gas flow rate on the degree of its purification from the finely dispersed particles, as well as on the change in the hydraulic resistance of this apparatus. This paper also shows that the main forces that make the greatest contribution to the purification of the gas flow from the finely dispersed particles are centrifugal and inertial. Moreover, the dependencies of the purification efficiency on the Stokes numbers are shown in this paper. The authors studied the change in the hydraulic resistance coefficient of this apparatus from the Reynolds numbers as well.

scholarly journals Hydraulic resistance accompanying waterjet cutting

Vestnik MGSU ◽  
2020 ◽  
pp. 399-408
Author(s):  
Lyudmila V. Volgina ◽  
Ivan A. Gusev
Keyword(s):  
Hydraulic Resistance ◽  
Two Phase Flow ◽  
Resistance Coefficient ◽  
Phase Flow ◽  
Hydraulic Systems ◽  
Two Phase ◽  
Pressure Losses ◽  
Hydraulic Resistance Coefficient ◽  
Complex Process ◽  
Physics Experiment

Introduction. Two-phase flow transmission is a complex process exposed to the influence of numerous factors. Its characteristics may depend on the physical properties of a flowing medium and on the properties of a pipeline, flow velocities, etc. A research into new types of hydraulic systems serves to identify the parameters that characterize the processes that accompany their transmission, especially if a multi-component flow is analyzed (a mix of water and abrasive particles). The mission of the research is to identify the value of hydraulic resistance coefficient in the course of transmission of a two-phase flow, or a mix of water and an abrasive. Materials and methods. A physics experiment, mathematical data processing methods, data description. Results. The co-authors have identified the hydraulic resistance coefficient value in the course of the mix transmission, as well as the parameters characterizing supplementary pressure losses in the course of the abrasive transmission. The experimental research enabled the co-authors to identify maximal water and mix application distances that reach 317 and 290 meters. Conclusions. The results, obtained by the co-authors, are the consequence of the pressure losses that occur in the course of mix transmission and the coefficients that characterize it. The flows considered in the article are used in the systems whose parameters are considerably different from those of traditional hydraulic engineering systems; therefore, any theoretical results obtained by the co-authors need experimental verification. Further, similar systems having different parameters must also be exposed to research to identify the relation between the pressure loss and the abrasive consumption rate and amount. The practical value of the research consists in the identification of maximal water and mix transmission and application distances providing that the operating parameters of the systems remain unchanged.

Odor plumes and how blue crabs use them in finding prey.

1994 ◽  
Vol 197 (1) ◽  
pp. 349-375
Author(s):  
M J Weissburg ◽  
R K Zimmer-Faust
Keyword(s):  
Turbulent Flows ◽  
Chemical Cues ◽  
Fluid Motion ◽  
Viscous Sublayer ◽  
Chemical Information ◽  
Chemical Stimulus ◽  
Turbulent Regime ◽  
Blue Crabs ◽  
Odor Plumes ◽  
Terrestrial Insects

Orientation of animals using chemical cues often takes place in flows, where the stimulus properties of odorants are affected by the characteristics of fluid motion. Kinematic analysis of movement patterns by animals responding to odor plumes has been used to provide insight into the behavioral and physiological aspects of olfactory-mediated orientation, particularly in terrestrial insects. We have used this approach in analyzing predatory searching by blue crabs in response to plumes of attractant metabolites released from the siphons of live clams in controlled hydrodynamic environments. Crabs proceed directly upstream towards clams in smooth-turbulent flows and show high locomotory velocities and few periods of motionlessness. Crabs assume more indirect trajectories and display slower locomotion and more stopping in rough-turbulent flows. This degradation of foraging performance is most pronounced as flow shifts from a smooth- to a rough-turbulent regime, where the change in hydraulic properties is associated with contraction of the viscous sublayer region of the boundary layer. Because flow in this region is quasilaminar, the viscous sublayer may be a particularly effective vehicle for chemical stimulus transmission, such that orientation is severely compromised when it is reduced or removed. Our results also suggest that rheotactic and chemical information are both necessary for successful orientation. Perception of chemical cues acts to bias locomotion upcurrent, and feedback from odorant stimulus distributions appears directly to regulate subsequent stopping and turning en route to prey. Although the mechanisms of orientation to odorant plumes displayed by insects and blue crabs are largely similar, blue crabs appear to rely more heavily on spatial and/or temporal aspects of chemical stimulus distributions than has been suggested for insect systems.

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