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

Numerical Investigation of Pneumatic Regulating on Low-Pressure Guide Vane

2015 ◽  
Vol 733 ◽  
pp. 554-557
Author(s):  
Ya Jie Qin
Keyword(s):  
Flow Rate ◽  
Guide Vane ◽  
Position Angle ◽  
Low Pressure ◽  
Flow Regulation ◽  
Main Stream ◽  
Low Pressure Turbine ◽  
Calculation Results ◽  
Loss Efficiency ◽  
The Impact

In order to reduce the turbine flow, injecting an airstream into the mainstream of the low-pressure turbine from the casing. A CFD analysis has been carried out to study the impact of jet parameters (jet position, Angle, flow rate and velocity) to the turbine flow. The calculation results show that when the low-speed region caused by the jet flow locates at the throat the flow regulating effect is the most obvious. In additional, when the jet is against the main stream or with a big flow rate, the turbine flow regulation is better, but the loss efficiency of the turbine will be significantly increased. The jet Mach number has little influence on the effect of flow regulation.

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.

Impact Of Transurethral Resection Of Prostate On International Prostate Symptom Score And Peak Urinary Flow Rate

2020 ◽  
Vol 16 (1) ◽  
pp. 11-15
Author(s):  
Md Waliul Islam ◽  
Md Abul Hossain ◽  
Md Nurul Hooda ◽  
Kazi Rafiqul Abedin ◽  
Husne Ara
Keyword(s):  
Flow Rate ◽  
Transurethral Resection ◽  
Urine Volume ◽  
T Test ◽  
Urinary Symptoms ◽  
Urinary Flow Rate ◽  
Transurethral Resection Of Prostate ◽  
Urinary Flow ◽  
Paired Student ◽  
The Impact

Objectives: To evaluate urinary symptoms and quality of life in patient with BPH before and after TURP. To determine the impact of TURP on the urinary symptoms (IPSS) and peak urinary flow rate. Methods: This study is prospective study carried out between 2010 and 2011 in the department of Urology, National Institute of Kidney Diseases & Urology. Total 102 cases were selected purposively according to selection criteria. Each patient was observed and followed up at 8 weeks (1st visit), 16 weeks (2nd visit) 24 weeks (3rd visit) after transurethral resection of prostate (TURP). IPSS score, QOL score also recorded and uroflowmetry was done to see the peak urinary flow rate (Qmax) of urine and voiding time. USG was done to see post voidal residual urine volume and DRE also done in selected cases. Data was complied and statistical analysis were done using computer based software, Statistical Package for Social Science (SPSS), using paired ‘t’ test. A P value <0.05 was taken as significance. Results: Before TURP, IPSS range 17-25 and mean 21.61+2.43, after TURP, range 0-7 and mean 4.27+1.71). Hence a significant improvement of IPSS was found from 2 months to 6 months follow up after TURP. The change was tested using “paired student ‘t’ test”. Before TURP Qmax range 7-12.2 and mean was 9.96+1.69, which became range 18-25 and mean was 22.61+2.28 after TURP and therefore change of mean Qmax was 12.64+2.69. The change was tested using “paired student ‘t’ test”. The change was found significant (P<0.001). Conclusion: Transurethral resection of prostate resolves obstructive symptoms, rapid improvement of urinary flow rate Bangladesh Journal of Urology, Vol. 16, No. 1, Jan 2013 p.11-15

The European Union and Global Governance

2017 ◽  
Author(s):  
Thomas Christiansen
Keyword(s):  
European Union ◽  
Global Governance ◽  
Final Section ◽  
The European Union ◽  
Test Bed ◽  
Way Of Life ◽  
New Ideas ◽  
The Impact ◽  
Global Powers

This chapter discusses whether the European Union has a distinctive take on, and may make a particular contribution to, global governance, as well as the reverse image of the impact that global governance has in the development of integration in Europe. This includes a focus on collective norms and interests as expressed through common institutions, policies, and activities. In doing so, the chapter compares and contrasts the evolution of a supranational order in Europe with the growth of global regimes and the emergence of a multipolar world, and explores the nature of the EU’s relationships with other global powers and regions. In a final section, the chapter asks whether the EU’s relationship with global developments is best seen as a test-bed for new ideas, procedures, and concepts; a construction for the defence of a privileged way of life; or an archaic remnant of a different era.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

Influence of rotating magnetic field on Maxwell saturated ferrofluid flow over a heated stretching sheet with heat generation/absorption

2019 ◽  
Vol 20 (5) ◽  
pp. 502 ◽  
Author(s):  
Aaqib Majeed ◽  
Ahmed Zeeshan ◽  
Farzan Majeed Noori ◽  
Usman Masud
Keyword(s):  
Magnetic Field ◽  
Temperature Field ◽  
Velocity Field ◽  
Differential Equations ◽  
Heat Transport ◽  
Viscous Dissipation ◽  
Heat Generation ◽  
Fluid Motion ◽  
Numerical Procedure ◽  
The Impact

This article is focused on Maxwell ferromagnetic fluid and heat transport characteristics under the impact of magnetic field generated due to dipole field. The viscous dissipation and heat generation/absorption are also taken into account. Flow here is instigated by linearly stretchable surface, which is assumed to be permeable. Also description of magneto-thermo-mechanical (ferrohydrodynamic) interaction elaborates the fluid motion as compared to hydrodynamic case. Problem is modeled using continuity, momentum and heat transport equation. To implement the numerical procedure, firstly we transform the partial differential equations (PDEs) into ordinary differential equations (ODEs) by applying similarity approach, secondly resulting boundary value problem (BVP) is transformed into an initial value problem (IVP). Then resulting set of non-linear differentials equations is solved computationally with the aid of Runge–Kutta scheme with shooting algorithm using MATLAB. The flow situation is carried out by considering the influence of pertinent parameters namely ferro-hydrodynamic interaction parameter, Maxwell parameter, suction/injection and viscous dissipation on flow velocity field, temperature field, friction factor and heat transfer rate are deliberated via graphs. The present numerical values are associated with those available previously in the open literature for Newtonian fluid case (γ 1 = 0) to check the validity of the solution. It is inferred that interaction of magneto-thermo-mechanical is to slow down the fluid motion. We also witnessed that by considering the Maxwell and ferrohydrodynamic parameter there is decrement in velocity field whereas opposite behavior is noted for temperature field.

Numerical Simulation of Cavitating Flow in a Francis Turbine

2008 ◽  
Author(s):  
Lingjiu Zhou ◽  
Zhengwei Wang ◽  
Yongyao Luo ◽  
Guangjie Peng
Keyword(s):  
Numerical Simulation ◽  
Transport Equation ◽  
Flow Rate ◽  
Suction Side ◽  
Cavitating Flow ◽  
Francis Turbine ◽  
Efficiency Change ◽  
Experiment Data ◽  
Calculation Results ◽  
Vapor Fraction

The 3-D unsteady Reynolds averaged Navier-tokes equations based on the pseudo-homogeneous flow theory and a vapor fraction transport-equation that accounts for non-condensable gas are solved to simulate cavitating flow in a Francis turbine. The calculation results agreed with experiment data reasonably. With the decrease of the Thoma number, the cavity first appears near the centre of the hub. At this stage the flow rate and the efficiency change little. Then the cavity near the centre of the hub grows thick and the cavities also appear on the blade suction side near outlet. With further reduce of the Thoma number the cavitation extends to the whole flow path, which causes flow rate and efficiency decrease rapidly.

scholarly journals Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance

2015 ◽  
pp. 473 ◽  
Author(s):  
Florence Schwarzenbach ◽  
Cecile Berteau ◽  
Orchidee Filipe-Santos ◽  
Tao Wang ◽  
Humberto Rojas ◽  
...  
Keyword(s):  
Flow Rate ◽  
Subcutaneous Injection ◽  
Injection Volume ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
The Impact

An Approach to Determine the Stiffness Reduction Factor of Tunnel Lining

2011 ◽  
Vol 243-249 ◽  
pp. 3659-3662
Author(s):  
Hai Ying Zhou ◽  
Li Xin Li ◽  
Ting Guo Chen
Keyword(s):  
Numerical Analysis ◽  
Flexural Rigidity ◽  
Resistance Coefficient ◽  
Reduction Factor ◽  
Tunnel Lining ◽  
Soil Resistance ◽  
Stiffness Reduction ◽  
Simplified Method

Based on the segmental joint tests, it was found that the practical range of joint flexural rigidity was in range of 8500-29000kN•m/rad. A simplified method for determining the stiffness reduction factor of tunnel lining() was proposed using results from the segmental joint tests in which some parameters were obtained by calibration against a 3D Numerical analysis. The influence of joint flexural rigidity, soil resistance coefficient, thickness of tunnel lining and tunnel calculation radius on the stiffness reduction factor of tunnel lining was examined. The stiffness reduction factor can be simply expressed as a function of joint flexural rigidity ratio, soil resistance coefficient, thickness of tunnel lining and tunnel calculation radius for the typical tunnel lining.

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