Determination of hydraulic resistance of channels using spectral geometry methods

2021 ◽  
Author(s):  
Alex Baron
Keyword(s):  
Hydraulic Resistance ◽  
Cross Section ◽  
Dissipation Rate ◽  
Average Energy ◽  
Energy Dissipation Rate ◽  
High Accuracy ◽  
Spectral Geometry ◽  
Constant Cross Section ◽  
Theoretical Justification

Abstract In this paper, we propose a new method for calculation of hydraulic resistance of channels with constant cross-section. The method is based on the obtained estimates for the average energy dissipation rate in a turbulent flow. The first part of the paper is devoted to theoretical justification of the method. The second part is devoted to calculation of hydraulic resistance of various channels using the abovementioned method and comparison of these values with the known results. The proposed method allows for calculation of hydraulic resistance of various channels with sufficiently high accuracy and is based only on the information about the channel geometry.

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 High-accuracy determination of theU238/U235fission cross section ratio up to≈1GeV at n_TOF at CERN

2015 ◽  
Vol 91 (2) ◽  
Author(s):  
C. Paradela ◽  
M. Calviani ◽  
D. Tarrío ◽  
E. Leal-Cidoncha ◽  
L. S. Leong ◽  
...  
Keyword(s):  
Cross Section ◽  
High Accuracy ◽  
Cross Section Ratio ◽  
Section Ratio ◽  
Accuracy Determination

scholarly journals Towards the high-accuracy determination of the238U fission cross section at the threshold region at CERN – n_TOF

2016 ◽  
Vol 111 ◽  
pp. 02002 ◽  
Author(s):  
M. Diakaki ◽  
L. Audouin ◽  
E. Berthoumieux ◽  
M. Calviani ◽  
N. Colonna ◽  
...  
Keyword(s):  
Cross Section ◽  
Fission Cross Section ◽  
High Accuracy ◽  
Threshold Region ◽  
Accuracy Determination

Observations of Small-Scale Processes Associated with the Internal Tide Encountering an Island

2005 ◽  
Vol 35 (9) ◽  
pp. 1553-1567 ◽  
Author(s):  
Craig L. Stevens ◽  
Edward R. Abraham ◽  
C. Mark Moore ◽  
Philip W. Boyd ◽  
Jonathan Sharples
Keyword(s):  
Dissipation Rate ◽  
East Coast ◽  
Average Energy ◽  
Internal Tide ◽  
Propagation Speed ◽  
Energy Dissipation Rate ◽  
Nonstationary Time Series ◽  
Small Scale ◽  
Vertical Diffusivity ◽  
Order Of Magnitude

Abstract Current-meter, temperature, and microstructure observations of the large-amplitude internal tide shoaling on the continental shelf of the east coast of northern New Zealand show the complexity of the internal kinematics and mixing. The propagation speed of the main internal wave was around 0.3 m s−1, and nonstationary time series analysis was used to locate the trailing short-wavelength internal waves in frequency (periods of around 40 min) and tidal-phase space. The average energy dissipation rate (5 × 10−8 m2 s−3) was an order of magnitude smaller than that observed on the open shelf in other studies, but peaks in dissipation rate were measured to be much greater. The vertical diffusivity of heat was around 10−4 m2 s−1, comparable to, or greater than, other studies. Examples of the scale and sporadic nature of larger mixing events were observed. The behavior was complicated by the nearby steeply shoaling coast of the Poor Knight Islands. Consistent reflected wave energy was not apparent.

scholarly journals Scaling bounds on dissipation in turbulent flows

2015 ◽  
Vol 777 ◽  
pp. 591-603 ◽  
Author(s):  
Christian Seis
Keyword(s):  
Fluid Dynamics ◽  
Turbulent Flows ◽  
Dissipation Rate ◽  
Equations Of Motion ◽  
Average Energy ◽  
Energy Dissipation Rate ◽  
Porous Medium Convection ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard ◽  
Rigorous Method

We propose a new rigorous method for estimating statistical quantities in fluid dynamics such as the (average) energy dissipation rate directly from the equations of motion. The method is tested on shear flow, channel flow, Rayleigh–Bénard convection and porous medium convection.

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